fabricating longer runner LT1 intake manifold

Been thinking of fabricating a one off LT1 manifold for my current LT1 build that will have longer runners to really kick in midrange and low topend torque and power. The LS1 manifold design looks like a workable design with runner at least twice as long at the stock LT1 runners. The engine is a 383 with bowl ported heads that flow quite a bit better than the stockers and will likely be running a GM hot cam ( unless I find something that looks like it would be a better compromise of low/mid torque with solid horsepower up top. I'm running an auto transmission. From the info. I've run across so far I think making a copy of the general layout of the LS1 manifolds might be the easiest to pull of without tons of time put in it. Anyone know of this having been done or have any general information that might be helpful?
Thanks, Michael

I don't know of anyone who has used a LS1 manifold as a base for a conversion. The new fad is converting a single plane manifold like the Super Vic or Victor Jr to EFI. Search for single plane conversion and you can get lots of info.

You're not gonna find a whole lot of info on something like this, basically because the man who manages to engineer an LTx intake that's based on an LSx folded hands intake will potentially have alot of money (or races) at stake, if you get my drift.

No cause you can't do it. The intake runners are next to each other not spread out like a LS1 intake.

Basically you can't do this cheaply, that's why nobody does it that way.

Bret

The idea isn't to convert an LS1 intake, if the port configuration matched that would be fine. From some of the dyno charts I've seen on the lingenfelter superram intakes I'd bet they'd feel way faster on the street with a hot cammed 383 and automatic than the LT1 intake. I'd bet that torque and throttle response at small throttle openings ( 1/8 to 1/2 throttle) would be far stronger with the mid length tuned runners while only giving up a modest amount of peak HP up to 5500 or 6000 RPM's.
The problem with the superram is they cost a grand, they are prone to leaks and are a bitch to R&R. I've fabbed sheet metal intakes and converted carb intakes to multiport EFI so I have a pretty good idea of the time involved with building one. The general layout of the LS1 manifold looks like it might be promising because it has longer runners than the LT1 intake and is compact enough to facilitate easy removal in the LT1 engine bay.
From what I gather so far no one who's seen this post knows of any other manufactured or one off intakes for an LT1 with mid length runners other than the superram.
Thanks for the replies.

From what I gather so far no one who's seen this post knows of any other manufactured or one off intakes for an LT1 with mid length runners other than the superram.
Thanks for the replies.[/QUOTE]

Heeeeeere ya go

http://img143.imageshack.us/img143/4783/picture0152fq.jpg

Also Bret did a cut down stealthram, he may have a pic.



David

Oh, that's just awsome.:D

There was a shop in Berea Ohio that built a 96 Vette for the One Lap of America race that had a sheet metal manifold with long runners on an LT1. (supercharged) In the late 90s they also built special model Corvettes for Chevrolet. The name of the place was Mallet Motorsports. Owner was Chuck Mallet. They could make dam near anything for the LT1. Warning, they are very expensive! Im not sure if they are still in business, havent been by there in 5 yrs.

From what I gather so far no one who's seen this post knows of any other manufactured or one off intakes for an LT1 with mid length runners other than the superram.
Thanks for the replies.

Heeeeeere ya go

http://img143.imageshack.us/img143/4783/picture0152fq.jpg

Also Bret did a cut down stealthram, he may have a pic.



David[/QUOTE]



That's the one I had Wilson do for me for the kids car.
Bring your checkbook as that's over 3500 dollars worth of intake.

that Wilson looks cast. Why aren't there more like it around?

that Wilson looks cast. Why aren't there more like it around?

I think I hold the patent on that one.:D
They made it look that way for the "stock" look.
3500+dollars is another reason.

So, how did it work?

Haven't done a full evaluation on it yet. Had a cam bearing failure(spring pressure and RR ratio). The block is having roller cam bearings installed right now.
We will see in a couple of months.
Wilson said it out flowed one of "his" Super Victor intakes.
This intake is WAY to big for the average build with stock head casting's. I have ProTopline heads that have been converted.

that Wilson looks cast. Why aren't there more like it around?

Cheston,

You would be amazed of what you can do with sheetmetal or weld. A glass beader and some steel shot and time and anything can look as cast.

Racerdude,

How much pressure and rocker arm did it take before you had the cam bearings go BOOM?

Bret

800 on the nose and 1.8RR'S
The bearings didn't go out,there was metal in the oil and I pulled it down to find the cam bearing's excessively worn. I figure it was from starting with no oil pressure even though it was primed the first time.After that it wasn't.
An accumulator would have prevented it but where ya gonna mount a 1gal unit. A two qt may have done it but it would be iffy and the mounting thing again.
Roller bearings will fix it permanently.

I agree. I really like a Accusump 1 gal for drag race motors, nothing wrong with priming the system before hand. Plus the other issue for you is the smaller cam bearings to start with. A SBC 1.968" isin't very big, but a 55mm LS1 journal is a different beast.

Bret

I agree. I really like a Accusump 1 gal for drag race motors, nothing wrong with priming the system before hand. Plus the other issue for you is the smaller cam bearings to start with. A SBC 1.968" isin't very big, but a 55mm LS1 journal is a different beast.

Bret

Yep and the 50MM rollers are a beast also.
Could have gone with the BB ACL bearings but didn't know about the longevity of those either on the street. Trailer queen they would have been OK.

grammerman

I say that if you have the time and abillity go ahead and build one. It shouldn't be too hard. I'm assuming that you are building a plenum in the center with each runner running over the top of it and pulling air in from the oppisite side like the ls1 style intakes do. If you search I think you will be able to find some calculations to help you select the propper runner length size and plenum volume. Good luck and post back up if you build it.

I've been meaning to start on designing an F1 style intake manifold for a long time, just haven't got around to doing it. Besides, my welding skills are a little too limited for something like that. I think that's kind of the opposite of what you want, they tend to be very short runners, but maybe you could make a taller one?

Just an idea,

Jeremy

Well really something like this is needed, make your runner lenght whatever you want.

http://img328.imageshack.us/img328/2880/wilsonpw7.jpg



David

David,

What program was that drawing done with? I really need a some good 3-D modeling software. AutoCad just doesn't cut it anymore.

Thanks,
Jeremy

it looks like autocad 2006.

Not bad... but it'll be hard to stay symetrical (if that's your goal) with the SBC/LT1 port placement.

Nice to see the plenum volume is about TWICE that of a stock LT1. If you think the LT1 outside looks small, check out the salami-sized plenum some time...


I've seen two or three custom plenums on modified LT1 intakes here, and one in person at Speed Secrets. The longer runners would be very cool though... as would a phenolic spacer at the manifold gasket surface and under the intake, and maybe a direct injection design that ports the N20 and gas from the EGR and into the IAC circuit. :)


Just thinking out loud....

David,

What program was that drawing done with? I really need a some good 3-D modeling software. AutoCad just doesn't cut it anymore.

Thanks,
Jeremy


That pic was copied off of Wilson Manifold's website it is for an LS1.


David

it looks like autocad 2006.

Have you had any experience with it? I'm thinking about going with SolidWorks, not sure yet. I'd love to design a new intake manifold for my LT1, maybe I could get Bret to build it for me. As i've said before, my welding skills are limited.

Jeremy

I'm a fan of solid edge myself, just run through a few of the tutorials and you're on your way. Its pretty easy to pick up if you have any previous 2d cad experience.

If you happen to have $2600 laying around I know Hogan make a sheet metal LT1 intake. I've seen it in person and its awsome!!!

http://memimage.cardomain.net/member_images/3/web/747000-747999/747807_20_full.jpg

Nice Hogan Intake! but what are the numbers on it compared to a stock LT1 intake. My stock intake seems to start to show it limitations at about 5500and gets worse as RPM climbs to 6800. My MAP goes from about 100KPA at 4500 RPM to 94KPA at 6800. I have no issues with my CAI (its 4" all the way with no MAF, w/big K&N filter) . It's gotta be an intake manifold issue. This is on a weenie little 355, I would think more cubes would be more problems. I sure would like to test one of those Hogans back to back on the dyno. Think they would lend me one? :D

Steve

Nice Hogan Intake! but what are the numbers on it compared to a stock LT1 intake. My stock intake seems to start to show it limitations at about 5500and gets worse as RPM climbs to 6800. My MAP goes from about 100KPA at 4500 RPM to 94KPA at 6800. I have no issues with my CAI (its 4" all the way with no MAF, w/big K&N filter) . It's gotta be an intake manifold issue. This is on a weenie little 355, I would think more cubes would be more problems. I sure would like to test one of those Hogans back to back on the dyno. Think they would lend me one? :D

Steve

What throttle body are you running? I had the same issue when running a 52mm on my 383 turning similar RPM. The issue was cured by the AS&M monoblade where my MAP stayed at 99-100kpa until the limiter at 7000.

Isn't that intake pictured in the car on the first page a modified gm ram jet 350 intake?

Have you had any experience with it? I'm thinking about going with SolidWorks, not sure yet. I'd love to design a new intake manifold for my LT1, maybe I could get Bret to build it for me. As i've said before, my welding skills are limited.

Jeremy
not much, you can get a free 30 day trial from their website. most of my cad experience was on autocad '95 lite at school.

not much, you can get a free 30 day trial from their website. most of my cad experience was on autocad '95 lite at school.

I might have to download it to try it out. Did they even have 3 dimensional modeling in '95?;)

What throttle body are you running? I had the same issue when running a 52mm on my 383 turning similar RPM. The issue was cured by the AS&M monoblade where my MAP stayed at 99-100kpa until the limiter at 7000.


I'm running a 58MM Holley and the TB bores are appropriately opened up to 58 MM + a tad bit to avoid a step. The 58 mm TB yields about 8 sq inches of flow area compared to about 12 sq inches of flow area in my 4" CAI. You may have a point about the monoblade. Anybody have one laying around that I can do a before/after dyno test on??

Steve

Hey Steve, I have a Monoblade sitting in my garage. I bought it about a month ago, just havent had anytime to install it. Let me know what you have in mind, or when you would need it. I would be curious to see the before and after results myself. Do you have any pics of your 4" CAI? Let me know what you want to do.



Nick

I might have to download it to try it out. Did they even have 3 dimensional modeling in '95?;)
it did, i was just really bad at it. my class was all 2d drawing. i just looked up tutorials online to get the idea because i finished the class 3 weeks early and was bored.

I have a sheet metal intake with six inch runners. If someone can host the image I'll e-mail it so everyone can have a peek. The car gained 47 RWT @ 3000 rpm making more power everwhere until 6100 were it lost 20 some @ 7000 rpm. In the process of recamming the car to compensate and push the powerband back up some.

FYI.....I'm using a ASM monoblade for the TB.

Denny,

If you email the file to me I can put it on cardomain and link it. Just send it to the board E-mail.

Chris

it did, i was just really bad at it. my class was all 2d drawing. i just looked up tutorials online to get the idea because i finished the class 3 weeks early and was bored.

I know the feeling, I finished my cad class early in highschool and spent a month "carving" a LeMans car out of a solid block on AutoCad 2000.

I have a friend who is going to give me autocad '07 and solidworks '04, if I ever get around to designing a manifold I'll post pics on here. Maybe someone will think it's worth building.

Jeremy

I have a sheet metal intake with six inch runners. If someone can host the image I'll e-mail it so everyone can have a peek. The car gained 47 RWT @ 3000 rpm making more power everwhere until 6100 were it lost 20 some @ 7000 rpm. In the process of recamming the car to compensate and push the powerband back up some.

FYI.....I'm using a ASM monoblade for the TB.


www.imageshack.com


free hosting

David

Isn't that intake pictured in the car on the first page a modified gm ram jet 350 intake?



Thats what it started as, would have been cheaper just to get a full blown sheetmetal done.



David

I know the feeling, I finished my cad class early in highschool and spent a month "carving" a LeMans car out of a solid block on AutoCad 2000.

I have a friend who is going to give me autocad '07 and solidworks '04, if I ever get around to designing a manifold I'll post pics on here. Maybe someone will think it's worth building.

Jeremy
thats cool, you're better at it than me then! my schools version was hacked to work on xp and there were lots of errors and lite was real limited anyhow. Good luck designing one!

Here's a pic of the 4" CAI. It's probably overkill but at least it's one less thing to worry about. You can see I ditched the MAF with a speed density tune as well to further eliminate any restriction possibility


http://images1.snapfish.com/347667453%7Ffp343%3Enu%3D3239%3E573%3E844%3EWSNRCG %3D323396%3C966%3C45nu0mrj

Steve

Isn't that intake pictured in the car on the first page a modified gm ram jet 350 intake?

Yea.
The only thing left that is Ram Jet is the port flanges and injector holes.

Here's a pic of the 4" CAI. It's probably overkill but at least it's one less thing to worry about. You can see I ditched the MAF with a speed density tune as well to further eliminate any restriction possibility


http://images1.snapfish.com/347667453%7Ffp343%3Enu%3D3239%3E573%3E844%3EWSNRCG %3D323396%3C966%3C45nu0mrj

Steve

A K&N set up will flow in excess of 1300CFM with a 12" long K&N filter on it.

I'm running a 6" diameter X 9" long cylindrical K&N with a 4" inlet. I should have pretty god flow with that. It's about all I could get crammed in the fenderwell while keeping all of the inner fenderwell plastic intact. I forget the calculations but the K&N should be plenty big enough for the 355 @ 6800.

also,

"Hey Steve, I have a Monoblade sitting in my garage. I bought it about a month ago, just havent had anytime to install it. "

I'll need to take a look at what it will take to open up my twin 58MM bores in the intake manifold to fit a ASM monoblade.

I'm running a 6" diameter X 9" long cylindrical K&N with a 4" inlet. I should have pretty god flow with that. It's about all I could get crammed in the fenderwell while keeping all of the inner fenderwell plastic intact. I forget the calculations but the K&N should be plenty big enough for the 355 @ 6800.

also,

"Hey Steve, I have a Monoblade sitting in my garage. I bought it about a month ago, just havent had anytime to install it. "

I'll need to take a look at what it will take to open up my twin 58MM bores in the intake manifold to fit a ASM monoblade.


1300CFM is enough for the badest 406 on the planet.

1300CFM is enough for the badest 406 on the planet.
__________________
LR


Agreed.

I'd like to try out the badest 406 on the planet someday :D

Steve

I have a sheet metal intake with six inch runners. If someone can host the image I'll e-mail it so everyone can have a peek. The car gained 47 RWT @ 3000 rpm making more power everwhere until 6100 were it lost 20 some @ 7000 rpm. In the process of recamming the car to compensate and push the powerband back up some.

FYI.....I'm using a ASM monoblade for the TB.

http://memimage.cardomain.net/member_images/10/web/454000-454999/454131_115_full.jpg
http://memimage.cardomain.net/member_images/10/web/454000-454999/454131_116_full.jpg
http://memimage.cardomain.net/member_images/10/web/454000-454999/454131_117_full.jpg

Looks good!

Obviously I'm a bit biased, but I’m happy with how it came out. As with anything you need to do some tweaking to make it work, but wasn’t as much as I had originally expected. Now the trick is to turn all those low end gains into overall and higher rpm gains.

Hey Steve, I have a Monoblade sitting in my garage. I bought it about a month ago, just havent had anytime to install it. Let me know what you have in mind, or when you would need it. I would be curious to see the before and after results myself. Do you have any pics of your 4" CAI? Let me know what you want to do.



Nick

I have a 58mm TB sitting in my garage that was replaced by the monoblade. We were hitting the wall making over 465 rwhp and replaced the 58 with the monoblade to see if it was the issue. it wasn't and the air flow math said it wouldn't be but we too a chance just to see.

In the fall when the weather is better just for poops n grins we're going to put the 58 mmTB back on an dyno the sucker to see if there is any difference at all. My partners thinking is there may be a remote chance of even picking up a tiny bit over the monoblade. Dunno....we'll see but the 58 mmmTB is good for a lot more power than most are making here.

Good to see you back, Denny. Nice job!

Good to see you back, Denny. Nice job!


Thanks! Staying away on purpose. Just post on things I have done and have measured myself and pretty much leave it at that. Way too much smack talk and disrespect for me on these lists. That I can do w/o but felt I had some worthwhile info to share.

Thanks! Staying away on purpose. Just post on things I have done and have measured myself and pretty much leave it at that. Way too much smack talk and disrespect for me on these lists. That I can do w/o but felt I had some worthwhile info to share.

You did. Thanks!

It does take a thick skin sometimes on these forums. :) I've developed that (and some age spots) with advancing years. If smack talk is directed my way I always consider the source. There are some folks who's opinion of what I post makes a difference to me, but not too many of them talk smack. As for the others, they have me confused with someone who gives a fat rat's butt what they think of me.

I'm just here for the beer!

I have a 58mm TB sitting in my garage that was replaced by the monoblade. We were hitting the wall making over 465 rwhp and replaced the 58 with the monoblade to see if it was the issue. it wasn't and the air flow math said it wouldn't be but we too a chance just to see.


I kind believe the 58MM TB is plenty for a 355 also, but hey crazier things have happend. Thanks for the pics Denny, looks way cool but a shade too tall for an F-Body cowl. That Tq and RPM range change is astounding. I never knew the runner length could have that much effect. I'm anxious to see if you can bring it back up with a cam change.

Steve

I never knew the runner length could have that much effect. I'm anxious to see if you can bring it back up with a cam change.

Steve[/QUOTE]

The runner length effect fooled us also. Just wasn't expecting a 50lb increase in torque, thought it would be all on top. Live n learn for sure. (Got a good one on expensive stepped headers n merge collectors also)

Got two cams picked out and if the first doesn't work, well then there is another one we'll try then. And if that doesn't work......don't know what in the hell to do.

Care to share what you learned with the headers?



David

Thanks for all the interesting replies. The two custom intakes that had photos posted are pretty cool. I was doing some research on variable volume/length intake manifolds a couple days ago and ran up on some interesting designs. I think it was Audi that makes one that has long runners with a short runner Y-ed in just upstream of the injector. A butterfly valve opens where the long and short runner connect as RPM's come up to change the intake tuning. Don't know if there's enough room to make this practical on an LT1 F-body but seems like a pretty good design. Long torque enhancing runners that open up into top end short runners. I'm going to think on it some more and might wind up and build something stupid :)
Regards, Michael

Care to share what you learned with the headers?
David

Let's say it was a $2,000.00 lesson on diving into the pool w/o checking how deep the water is taking someone's word on it. We picked up nothing. Yep, CNC ports, 1 3/4th to 1 7/8th to a 3" Burns style merge collector with 2 1/2 reducer. And the dyno said zippo!

Haven't given up completely on the headers as couple hardcore racers I know say they are the real deal but the cam needs to be changed to get the most out of the headers.

Already got a couple of cams that we'll try and still doing some research but everything is on hold till the weather gets better. It was 107 here in Dallas with everyday over 100 degrees and orange polution alerts. Not exactly home run tuning weather.

Now you should hear the story about the exhaust vacuum bungs and hooking them up to the valve covers.

Thanks for all the interesting replies. The two custom intakes that had photos posted are pretty cool. I was doing some research on variable volume/length intake manifolds a couple days ago and ran up on some interesting designs. I think it was Audi that makes one that has long runners with a short runner Y-ed in just upstream of the injector. A butterfly valve opens where the long and short runner connect as RPM's come up to change the intake tuning. Don't know if there's enough room to make this practical on an LT1 F-body but seems like a pretty good design. Long torque enhancing runners that open up into top end short runners. I'm going to think on it some more and might wind up and build something stupid :)
Regards, Michael


Thats old school stuff, mid 90's Ford Probe v6 cars had that and 96 4 cam Cobras also had it...nothing new.


Why would you explore that when there are many proven power makers aout there?


David

David, are you saying because it's been done before or it's "old school" that it's not worth doing? The F1 race cars and one of the new Ferrari's use a variable length ( and I think variable cross section on the F1 stuff) intake setup to boost low end with out compromising top end. So what if a Ford Probe or Cobra used something similar 15 yrs. ago. Are you saying Ford spent the money to put this stuff on millions of engines and it didn't have any effect?
I'm interested in kicking out as much midrange torque and throttle response as possible with still decent top end pull ( 5500 to 6K without falling flat). The Accell Super Ram intake would probably work pretty well for this but I can't think of anything else off the shelf that would be suited here. Maybe you can suggest some other proven power makers for a NA small cammed ( 220ish on duration) 383 that would boost midrange with still decent top end?

subscribing.
This is great stuff.
Kory

Copying an F-1 style intake is exactly what i'm talking about. Though I think they adjust the height of the injectors (called trumpets) towards or away from the port to change the torque curve. Still, it couldn't be that hard to build.:shrug:

Copying an F-1 style intake is exactly what i'm talking about. Though I think they adjust the height of the injectors (called trumpets) towards or away from the port to change the torque curve. Still, it couldn't be that hard to build.:shrug:

Those "stacks" are called ram tubes. Long=low end,Short- high end TQ&HP.

Copying an F-1 style intake is exactly what i'm talking about. Though I think they adjust the height of the injectors (called trumpets) towards or away from the port to change the torque curve. Still, it couldn't be that hard to build.:shrug:

F1 used variable-length "trumpets" (or ram tubes for us Colonials) on the 3L V10s but they were outlawed with the 2.4L V8s now in use. I believe they moved about 50mm (2 in.).

http://www.dellorto.it/_Inglese_/tabelle_prodotti.asp?sottoarea=auto&tipo=collettori&sezione=1&sottosezione=2

That is a link to a dellorto web page with a picture and description of the variable length setup used on the Ferrari Enzo, it's at the bottom of the page. Looks like they are getting at least 4 to 5 inches of length variation in that application. Wouldn't be terribly hard to duplicate but it looks like you might have to get creative to fit it above the lifter valley on the LT1 F-body cars.

Here is a description of the Lamborghini variable geometry intake, which is made by Audi:

It is also endowed with dual-length intake manifolds..... This set-up allows for a resilient, flat torque output. To achieve all this the charge efficiency was increased at various speeds by adopting accurate and precise measures for gas dynamics that occur in the inlet and exhaust tracts.

To this end the continuously variable geometry intake manifold guarantees the correct base gas dynamic characteristics at low and high rev ranges. In the low ranges the long runner set-up is used, while in the high ranges the short runner set-up is in use. It's this arrangement that allows for 80% of the 510Nm to be churned out at just 1 500rpm. The opposite scenario is the case when it comes to power outputs occurring at the high rev ranges reaching 7 800rpm.


Pretty intersting technology that lets a motor with a 7800 RPM redline produce 80% of it's torque at 1500 RPM's. Of course it also uses variable intake valve timing and maybe a variable backpressure exhaust ( which the 1000cc sportbikes have used to bulk up the low end with great success since the late 1980's). We have all seen proof from dyno charts on TPI and LT1 intakes that longer runners can kick in a 20% or more increase in torque in the midrange at wide open throttle. One thing I rarely hear people consider is that the torque increase at low throttle openings ( say 1/8 or 1/4 throttle) in the midrange using tuned runners is probably closer to 50%. That's what made the stock TPI's feel like 454's when you blipped the throttle at 2500 RPM's.
Anyhow, whether one used a continuously variable length runner like the Ferrari Enzo or two separate runners, one short and one long like the Lamborghini the results would probably be pretty impressive.

http://www.dellorto.it/_Inglese_/tabelle_prodotti.asp?sottoarea=auto&tipo=collettori&sezione=1&sottosezione=2

That is a link to a dellorto web page with a picture and description of the variable length setup used on the Ferrari Enzo, it's at the bottom of the page. Looks like they are getting at least 4 to 5 inches of length variation in that application. Wouldn't be terribly hard to duplicate but it looks like you might have to get creative to fit it above the lifter valley on the LT1 F-body cars.

Here is a description of the Lamborghini variable geometry intake, which is made by Audi:

It is also endowed with dual-length intake manifolds..... This set-up allows for a resilient, flat torque output. To achieve all this the charge efficiency was increased at various speeds by adopting accurate and precise measures for gas dynamics that occur in the inlet and exhaust tracts.

To this end the continuously variable geometry intake manifold guarantees the correct base gas dynamic characteristics at low and high rev ranges. In the low ranges the long runner set-up is used, while in the high ranges the short runner set-up is in use. It's this arrangement that allows for 80% of the 510Nm to be churned out at just 1 500rpm. The opposite scenario is the case when it comes to power outputs occurring at the high rev ranges reaching 7 800rpm.


Pretty intersting technology that lets a motor with a 7800 RPM redline produce 80% of it's torque at 1500 RPM's. Of course it also uses variable intake valve timing and maybe a variable backpressure exhaust ( which the 1000cc sportbikes have used to bulk up the low end with great success since the late 1980's). We have all seen proof from dyno charts on TPI and LT1 intakes that longer runners can kick in a 20% or more increase in torque in the midrange at wide open throttle. One thing I rarely hear people consider is that the torque increase at low throttle openings ( say 1/8 or 1/4 throttle) in the midrange using tuned runners is probably closer to 50%. That's what made the stock TPI's feel like 454's when you blipped the throttle at 2500 RPM's.
Anyhow, whether one used a continuously variable length runner like the Ferrari Enzo or two separate runners, one short and one long like the Lamborghini the results would probably be pretty impressive.



The answer really is simple, CUBIC INCHES and a long LSA short duration cam will give you what you want. Low end grunt.

IMO, the reason the above engines were done that way was to help a smaller CI engine make torque in lower rpm ranges. A large bore V8 doesnt have that issue...but if you want to split hairs and re-invent the wheel, you got more time than I have...have fun. GM spent a few $'s on engineering the LT1 intake, overall it does a damn good job. Past that a carb conversion, and past that a sheetmetal....Stock LT1 intakes have gone in the 10's normally aspirated, and low 11's with stock heads....but let us know how it goes.


David

Certainly using tuning tricks like variable intakes are a good idea on small engines. The Ferrari Enzo is a 6.0 liter engine and the Lamborghini engine I mentioned is 5 liters. Neither really what most would call small engines but they are cammed up for a lot of topend power (660 hp at 7800 RPM's on the Enzo). The intake and exhaust resonance tuning lets them produce bigtime horsepower yet avoid the crappy lowend and midrange that usually comes with the territory. It's interesting to consider that with a functional variable resonance intake you can install more cam/head and still wind up with strong midrange.

Ford used that system with the flaps in '86 an the V6 Escort and every 4.6 has it.
It's 20+ year old tech.

So could a system be built for an LT1 to control exhaust flow? Maybe you could use a nitrous window switch to control it? I'd love to be able to overcam my motor and not suffer low-end torque loss.

So could a system be built for an LT1 to control exhaust flow? Maybe you could use a nitrous window switch to control it? I'd love to be able to overcam my motor and not suffer low-end torque loss.

Ford just controls the intake.
Ya control the exhaust with cam timing NOT with flaps that will be burnt up/stuck in no time.
The LT1/4 isn't a 500,000 dollar exotic where if ya owned the 500,000 dollar car ya could afford the up keep.

I have an exhaust valve here off a Suzuki GSXR 1000, I bought it off ebay a while back to play with a variable back pressure exhaust on a four stroke motocross bike I was modifying. Never had time to do that but the variable intake I was playing with on the same bike made a huge improvement in low/mid with a small loss of overrev.
The exhaust valves on many of the bikes is a simple butterfly valve, the housing shaft and plate are all stainless steel. I imagine the stuff on the Ferraris and such is similar. The sport bikes are getting around 180 horsepower per liter now ( 1026 horsepower if you had a 350 with the same hp/liter) and obviously aren't cammed for low end. With the exhaust valves they are pretty damned responsive and linear in the low/mid RPM ranges. They don't pick up a great amount of wide open throttle horsepower from the exhaust valves but the part throttle improvement is very impressive.
Why an exhaust valve would necessarily be unreliable and expensive I'm not sure. The ones on the bikes are plenty reliable, at least as reliable as the valvetrain used with big cams in the race motors a lot of people on here build. The electric exhaust cutout valves are pretty reliable and yet they see a good deal of heat.
I think that even with a simple control system like a vacuum solenoid that would open the exhaust valve as manifold vacuum dropped you'd see a good gain. I think the reason more people don't tinker with stuff like this is they are stuck in an intellectual rut and only think in terms of "old school" technology they are familiar with like fuel injection or bigger cams which have been available for 40 years. Don't let other people scare you away from tinkering with new stuff, it can be fun and even occasionally rewarding.

I have an exhaust valve here off a Suzuki GSXR 1000, I bought it off ebay a while back to play with a variable back pressure exhaust on a four stroke motocross bike I was modifying. Never had time to do that but the variable intake I was playing with on the same bike made a huge improvement in low/mid with a small loss of overrev.
The exhaust valves on many of the bikes is a simple butterfly valve, the housing shaft and plate are all stainless steel. I imagine the stuff on the Ferraris and such is similar. The sport bikes are getting around 180 horsepower per liter now ( 1026 horsepower if you had a 350 with the same hp/liter) and obviously aren't cammed for low end. With the exhaust valves they are pretty damned responsive and linear in the low/mid RPM ranges. They don't pick up a great amount of wide open throttle horsepower from the exhaust valves but the part throttle improvement is very impressive.
Why an exhaust valve would necessarily be unreliable and expensive I'm not sure. The ones on the bikes are plenty reliable, at least as reliable as the valvetrain used with big cams in the race motors a lot of people on here build. The electric exhaust cutout valves are pretty reliable and yet they see a good deal of heat.
I think that even with a simple control system like a vacuum solenoid that would open the exhaust valve as manifold vacuum dropped you'd see a good gain. I think the reason more people don't tinker with stuff like this is they are stuck in an intellectual rut and only think in terms of "old school" technology they are familiar with like fuel injection or bigger cams which have been available for 40 years. Don't let other people scare you away from tinkering with new stuff, it can be fun and even occasionally rewarding.


"Old School Tech has won many of race and unless ya got the budget of a F-1 team then trying to reinvent the wheel on a SBC is ridiculous.Ya can make them run in the 6's and if ya need more then go to a mountain motor where parts are readily available. THAT'S OLD SCHOOL THINKING.Real smart IMO:)

I have an exhaust valve here off a Suzuki GSXR 1000, I bought it off ebay a while back to play with a variable back pressure exhaust on a four stroke motocross bike I was modifying. Never had time to do that but the variable intake I was playing with on the same bike made a huge improvement in low/mid with a small loss of overrev.
The exhaust valves on many of the bikes is a simple butterfly valve, the housing shaft and plate are all stainless steel. I imagine the stuff on the Ferraris and such is similar. The sport bikes are getting around 180 horsepower per liter now ( 1026 horsepower if you had a 350 with the same hp/liter) and obviously aren't cammed for low end. With the exhaust valves they are pretty damned responsive and linear in the low/mid RPM ranges. They don't pick up a great amount of wide open throttle horsepower from the exhaust valves but the part throttle improvement is very impressive.
Why an exhaust valve would necessarily be unreliable and expensive I'm not sure. The ones on the bikes are plenty reliable, at least as reliable as the valvetrain used with big cams in the race motors a lot of people on here build. The electric exhaust cutout valves are pretty reliable and yet they see a good deal of heat.
I think that even with a simple control system like a vacuum solenoid that would open the exhaust valve as manifold vacuum dropped you'd see a good gain. I think the reason more people don't tinker with stuff like this is they are stuck in an intellectual rut and only think in terms of "old school" technology they are familiar with like fuel injection or bigger cams which have been available for 40 years. Don't let other people scare you away from tinkering with new stuff, it can be fun and even occasionally rewarding.


I dont know of ANY sportbike making 180HP per liter, ZX-14 is the closest, it is 1.3 liters and makes 170 or so HP at the crank. Again a small bore engine needing rpm to make power as most all exotic car engines(small bore, multi valve engine setup)

If the flapper in the exhaust is so good why did all my buddies throw them in the garbage with an aftermarket pipe, picked up upwards of 12 RWHP(with a map) and were MUCH faster? Just like EVERY other sportbike rider? Including myself( Hindle race pipe on my Busa) .


Most guys who raced 4.6 mod motor Mustangs took the flapper valves out of the intake and made more power and went quicker.



David

http://i32.photobucket.com/albums/d31/RicksActionShots/DSC_2662.jpg


[IMG]http://www.accufabracing.com/mustan1b.jpg

http://www.accufabracing.com/redcar5.jpg

Ya could have something like these if ya didn't spend all your time and money on diddling with stuff.

The bottom car runs 6.60's with a 4.6 twin turbo.Fastest 4.6 on the planet.
The Teal one has a 4.6 with a Vortec blower.First 4.6 in the 8's
I raced/turned wrenches on both cars for John when I lived out there so the flapper blade thing is understood on a Ford. Got a fair understanding on building race engines also.

So at what point does a sheet metal intake start showing gains for a ported heads and big cam combo?

Do you need to go to aftermarket heads or could something like an LE2 heads and cam combo benefit?

So at what point does a sheet metal intake start showing gains for a ported heads and big cam combo?

Do you need to go to aftermarket heads or could something like an LE2 heads and cam combo benefit?

IMO a sheet metal only reduces the % of loss to the head flow. If ya got a stroker and want BIG power ya go to BIG heads.330CFM head flow is capable of making about 680FWHP everything else being spot on. A GOOD sheet metal will cut 2/3% off of that and a stock LT1 will take off 12/15%. That's using the rule of thumb formula on the HP-head flow numbers.
Buy the BIGGEST set of heads ya can afford and build the engine around them.But don't expect a set flowing 280CFM to support a 396CI.If ya got 280CFM heads build a 356 with good compression and a GOOD intake,cam it accordingly and have fun.

Here's a pic of the 4" CAI. It's probably overkill but at least it's one less thing to worry about. You can see I ditched the MAF with a speed density tune as well to further eliminate any restriction possibility


http://images1.snapfish.com/347667453%7Ffp343%3Enu%3D3239%3E573%3E844%3EWSNRCG %3D323396%3C966%3C45nu0mrj

Steve

Steve,
Could I ask what materials you used to fab that 4 inch CAI, especially that elbow? Did you paint it or have it coated? I've been considering something similar for mine, since I removed the ABS and have the space. Thanks.
Tim

Tim,

I used Mandrel bent uncoated steel tubing and Tig welded sections together. Then had it powder coated. The Filter is a K&N:

RD-1460 Product Specifications
Product Style: Round Straight Universal Air Filter
Flange Inside Diameter: 4 in (102 mm)
Flange Length: 1 in (25 mm)
Flange Type: Centered
Height: 9 in (229 mm)
Outside Diameter: 7 in (178 mm)
Top Style: Rubber
Top Material/Finish: None
Filter Re-Oiling Amount: 2.24 oz (66 ml)
Flanges: 1
Inner Wire: No
Weight: 2.4 lb (1.1 kg)
Product Box Length: 14.4 in (366 mm)
Product Box Width: 7.4 in (188 mm)
Product Box Height: 7.8 in (198 mm)


It's about the biggest you can fit in the fenderwell and keep all of the OEM plastic in tact.

The Elbow is fiberglass. There was a guy on E-bay making and selling these. He makes them with a 3.5" diameter inlet and he custom made me one with a 4" inlet to match up with the rest of the system. His quality is pretty good but not perfect. I had some cleanup and smoothing on the inside of the elbow. The elbow came in black and I did no painting on it. This is his Ebay name is
lt1pilot. I'm not sure he still makes them.
The 4" elbow really didn't pick up anything on the dyno or make any difference in my loss of MAP at 6800 over a stock GM elbow.

A couple of you dummies are stinking up this thread. If you have a problem with people discussing advanced tech stuff like exhaust valves and variable resonance intakes then maybe you shouldn't be in this area.

http://www.aperaceparts.com/tech/05gsxr1000.html

http://www.motorbyte.com/mmm/pages/2004/64/review64a.htm

If you don't want to click on the links that's 175.5 crankshaft horsepower for the 05 GSXR 1000 and 184 for the Suzuki ZX 10 which is also 1000 cc's. If you're not good at math that averages out pretty close to 180 horsepower per liter. Pulling the exhaust valve off the sport bikes is an OK thing if you're mainly after peak power. If you were interested in midrange and low end throttle response as well as topend( that's what this thread is about) then you'd be stupid to pull the exhaust valve because you just hamstrung your lowend by tearing off some very effective technology. Some people confuse the modest peak horsepower gain they get from a loud exhaust on these bikes with the slight increase made by removing the exhaust valve. Replacing a quiet and somewhat restrictive factory exhaust with a straight through racing pipe is bound to give you a few horsepower, but just because your threw away the exhaust valve at the same time doesn't mean the exhaust valve made all the power.

As for racerdude, I think this section is for advanced tech. If you want to put people down for thinking out of the box then you're posting in the wrong area. There is a turbo and supercharged area for people to brag about how fast the cheater engine somebody let them change sparkplugs on was.
You two should look around, not everybody is only interested in max effort race engines. A fair number of posts on here are about people buying a new set of 195cc heads or a small cam by CHOICE. If you don't have something constructive to offer about the original topic, longer runner intakes for LT1 engines or some other related midrange torque builder for NA, street driven engines then buzz off. That's what we're trying to discuss here and the bull**** is getting neck deep.

A couple of you dummies are stinking up this thread. If you have a problem with people discussing advanced tech stuff like exhaust valves and variable resonance intakes then maybe you shouldn't be in this area.

http://www.aperaceparts.com/tech/05 gsxr1000.html

http://www.motorbyte.com/mmm/pages/2004/64/review64a.htm

If you don't want to click on the links that's 175.5 crankshaft horsepower for the 05 GSXR 1000 and 184 for the Suzuki ZX 10 which is also 1000 cc's. If you're not good at math that averages out pretty close to 180 horsepower per liter. Pulling the exhaust valve off the sport bikes is an OK thing if you're mainly after peak power. If you were interested in midrange and low end throttle response as well as topend( that's what this thread is about) then you'd be stupid to pull the exhaust valve because you just hamstrung your lowend by tearing off some very effective technology.

As for racerdude, I think this section is for advanced tech. If you want to put people down for thinking out of the box then you're posting in the wrong area. There is a turbo and supercharged area for people to brag about how fast the cheater engine somebody let them change sparkplugs on was.
You two should look around, not everybody is only interested in max effort race engines. A fair number of posts on here are about people buying a new set of 195cc heads or a small cam by CHOICE. If you don't have something constructive to offer about the original topic, longer runner intakes for LT1 engines or some other related midrange torque builder for NA, street driven engines then buzz off. That's what we're trying to discuss here and the bull**** is getting neck deep.



Magazine racer I see, those bikes dont make that power, the newer "liter" bikes make mid to high 150's at the wheel on the average dyno-jet, so they lose 25 to 30 hp through drivetrain loss? Umm ok. 184 ram air assisted hp? Wonder how they ACTUALLY tested that figure?

As far as I know 95% of people on this board are after bang for the buck IOW what works. If you want to develop a new wheel more power to ya. I now a "little" about bikes in the real world. I am out, over.

BTW your top link in INOP


David

I have owned two vehicles with variable runner length intakes...an 89 SHO, and my 3.8 Minivan. My SHO would suprise alot of 5.0 jockeys....I loved that engine!
My 3.8 ford is a split port really simple design with blades that open a shorter runner. 138,000 miles witout a problem..... lots of torque.
Now making it work on an LT1 will be difficult...hell no one has even come up with a fixed longer runner manifold. If you can pull it off....I say go for it! There is an advantage to this...otherwise the factory's would not bother, but most average people do not have the budget or resources to engineer this; however, hotrodders have always proven experts wrong! If you can get the torque of the superram and the hp of a super victor and then fit it under the hood.......may be impossible? Don,t get me wrong I do not mean to be discouraging just giving my 2cents.

A couple of you dummies are stinking up this thread. If you have a problem with people discussing advanced tech stuff like exhaust valves and variable resonance intakes then maybe you shouldn't be in this area.

http://www.aperaceparts.com/tech/05gsxr1000.html

http://www.motorbyte.com/mmm/pages/2004/64/review64a.htm

If you don't want to click on the links that's 175.5 crankshaft horsepower for the 05 GSXR 1000 and 184 for the Suzuki ZX 10 which is also 1000 cc's. If you're not good at math that averages out pretty close to 180 horsepower per liter. Pulling the exhaust valve off the sport bikes is an OK thing if you're mainly after peak power. If you were interested in midrange and low end throttle response as well as topend( that's what this thread is about) then you'd be stupid to pull the exhaust valve because you just hamstrung your lowend by tearing off some very effective technology. Some people confuse the modest peak horsepower gain they get from a loud exhaust on these bikes with the slight increase made by removing the exhaust valve. Replacing a quiet and somewhat restrictive factory exhaust with a straight through racing pipe is bound to give you a few horsepower, but just because your threw away the exhaust valve at the same time doesn't mean the exhaust valve made all the power.

As for racerdude, I think this section is for advanced tech. If you want to put people down for thinking out of the box then you're posting in the wrong area. There is a turbo and supercharged area for people to brag about how fast the cheater engine somebody let them change sparkplugs on was.
You two should look around, not everybody is only interested in max effort race engines. A fair number of posts on here are about people buying a new set of 195cc heads or a small cam by CHOICE. If you don't have something constructive to offer about the original topic, longer runner intakes for LT1 engines or some other related midrange torque builder for NA, street driven engines then buzz off. That's what we're trying to discuss here and the bull**** is getting neck deep.


Yo,listen up.
I HAVE a long runner intake.I DON'T diddle.
Those pictures are of some I have worked on. Post your little cam,runner pictures with the times.
Re inventing a SBC is useless.

If it's neck deep on your end ya need to stop producing the BS.

Giving those that don't know, the wrong info doesn't make their life easier. If ya want to diddle go for it but don't try to say it's the spot on thing to do.

Well, without trying to encourage arguement...

I can see a real benefit to variable intake runners/exhaust pressures on the street, if not on the drag strip.

I'm not saying the exhaust valves really help the sport bikes that much. Some of the better 1 liter bikes weigh around 370lbs. so low-end torque only matters so much. Heck when I ride my roommates YZF R1 I am pretty happy about the lack of torque down low, but I'm not a great rider.

Still, if some of us with the knowledge and ambition to re-invent the wheel want to give it a try then just let us. Those of us who really are motivated will do it no matter what anyone else says, and those of us who are full of crap will probably never even attempt it.

1racerdude, you are obviously more experienced in racing and building race motors than I. Maybe someday you will get tired of doing the same old thing and try something a little more unorthodox. Of course, I wouldn't blame you if you didn't, I doubt sub-9 second quarter-miles gets old very fast.

Respectfully,
Jeremy

Well, without trying to encourage arguement...

I can see a real benefit to variable intake runners/exhaust pressures on the street, if not on the drag strip.

I'm not saying the exhaust valves really help the sport bikes that much. Some of the better 1 liter bikes weigh around 370lbs. so low-end torque only matters so much. Heck when I ride my roommates YZF R1 I am pretty happy about the lack of torque down low, but I'm not a great rider.

Still, if some of us with the knowledge and ambition to re-invent the wheel want to give it a try then just let us. Those of us who really are motivated will do it no matter what anyone else says, and those of us who are full of crap will probably never even attempt it.

1racerdude, you are obviously more experienced in racing and building race motors than I. Maybe someday you will get tired of doing the same old thing and try something a little more unorthodox. Of course, I wouldn't blame you if you didn't, I doubt sub-9 second quarter-miles gets old very fast.

Respectfully,
Jeremy


No.. 8/9 second passes don't get old,neither does dirt track sprint cars, but at my age can't stand the rush. Old heart and lungs go crazy.:D
Don't really care what is invented,just don't want the younger guys that don't know any better 'bout an LT1/SBC to get the idea this is the correct R&D.
I try to steer them to get the most BANG for the buck and to not spend money/time on the trick of the week.


Like I said earlier ya can get a SBC to run in the 6's and if that ain't enough build a mountain motor.
Don't think flappers installed anywhere would help them and people like Kasse,Shaftroff,Rhear-Morrison,ect don't use them--knowing if there was benefit they would be,knowing they are aware of the set up.That kind of backs up my position.

Yeah, I don't think it's really going to get me into the 10's or anything on motor. But if my 355 with a GM 847 cam will get a little of it's low end pull back from an exhaust flap I scavange off of a bike...I'll give it a try.

But the variable length intake runners, I don't think you can argue that on the street. It's not going to be the best low-end for stump pulling or High-end for drag racing, but good power all across the board is all i'm looking for in my daily driver. A little more than the guy beside me anyway.:D

Yeah, I don't think it's really going to get me into the 10's or anything on motor. But if my 355 with a GM 847 cam will get a little of it's low end pull back from an exhaust flap I scavange off of a bike...I'll give it a try.

But the variable length intake runners, I don't think you can argue that on the street. It's not going to be the best low-end for stump pulling or High-end for drag racing, but good power all across the board is all i'm looking for in my daily driver. A little more than the guy beside me anyway.:D


If ya want more low end do it with a cam and open up your intake SYSTEM and give it the max 9.0 DCR all good for low end.
Did I mention a gear.

But that is the problem with a cam, getting more low-end will usually sacrifice top-end. I like the top-end power, there are times I go through a particularly curvy stretch of road and never drop below 4500 rpm. I have a nitrous cam I am about to install that will be killer on the lower revs but I doubt it will be as powerful (peak power) up top. Of course, that's why I'm going to spray my way into the 9's, while still retaining daily driving fun:D .

But that is the problem with a cam, getting more low-end will usually sacrifice top-end. I like the top-end power, there are times I go through a particularly curvy stretch of road and never drop below 4500 rpm. I have a nitrous cam I am about to install that will be killer on the lower revs but I doubt it will be as powerful (peak power) up top. Of course, that's why I'm going to spray my way into the 9's, while still retaining daily driving fun:D .

:thumb:

It seems fairly obvious why Reher Morrison or most other RACE ENGINE builders don't fool with flaps or valves in the induction and exhaust system. In many instances the rules don't allow it. Even if they did race engines are a specialized piece of hardware that by their very design aren't called on to produce strong output over a wide RPM range in most cases. You can bet if the engines were used in such a way that a broader power delivery would help win races( and the rules allowed) that all the race engine builders would have flaps in their exhaust and valves in their intakes.
No one has claimed that having a dual length intake or variable back pressure exhaust would do much to help you outrun your buddy. What has been said is that they can make the vehicle more pleasurable to tool around the street in. Someone would have to disregard just about every other section on this site where talk is dominated by heads, cam and exhaust to come up with the notion that resonance tuning is going to be a fruitful way for them to better their quarter mile time.
It doesn't take a rocket scientist to deduce that the the broader your power range the more satisfying an engine will perform as a daily driver. A 454 with the same peak horsepower as a 302 is going to be much more fun to blitz around the street on because the power is right there anytime you tickle the gas. You're not wide open or throttle closed at all times in a daily driven performance car. Ferrari, BMW, Lamborghini and many other lesser makes use this stuff for a reason and they build very fast daily drivers that still have good midrange torque.
If you like to tinker and have a daily driver that you will only tolerate a certain amount of cam/heads on then there is nothing illogical about tinkering with the intake or exhaust. It's been proven many times over that the flexibility and part throttle torque of a high performance engine can be improved a great deal with the proper use of these devices. If you have the time and motivation and enjoy building things then it makes perfect sense to me, assuming you don't have any goofy notion that the reason you're doing it is to make the car faster down the drag strip.
Regards, Michael

grammerman, you've got the talk, lets see the walk. Every thread you start always ends up with you having all the answers. My simple little question to you is, why do you even ask? If you have the know how and the money to experiment with your ideas, JUST DO IT. Let us know how it works out and if the results are worth the bang for the buck you'll be our hero and some of us will follow suit. ;) Have a good day. Really!!!

This thread was started to seek input from people who might have run across intakes systems for LT1's with longer runners, whether one off or production pieces. Thanks to the guys who posted info. on some of their stuff that was relevant. The idea is to use the best manageable combination of off the shelf or in some instances possibly fabricated parts to produce a 383 with good top end power and max. midrange with solid low end. The variable resonance stuff some of us have been bouncing ideas around about is the BEST way to enhance the engine's torque width that I'm aware of. Construction of such gizmotrons happens to be one of my talents. I used to do stuff on the level of making an intake with dual length runners separated by valves for a living and still do such things as a hobby from my home machine shop. I guess that means I'm coming from left field compared to most of the readership on here in regards to doing such things on a pretty regular basis. Just for the challenge and enjoyment mostly.
I do think I'm pretty darn smart but I don't have ALL the answers :D The problem with a couple of my threads ( in my opinion) has been people hijacking them and injecting self serving propoganda that wasn't relevant or accurate. Self serving or even arrogant is fine but misleading and destructive are not. Stuff like " I " know the best and only correct way and any other way is foolish, or the only way real hotrodders do it is...., or a 383 ain't worth a bildin iffin yas don't put a huge cam and 250 cc heads, or doing it some other than the normal way is a waste of time. A difference of opinion is one thing, but trying to invalidate someone else's approach or viewpoint without addressing it directly or logically is annoying. If trying to keep my thread going and on track means butting heads and information with other people then that's OK with me. I must be disrupting the normal order around here for some people, it seems like there's a lot of energy being exerted pushing their agendas. This comes at the expense of the usefulness or accuracy of the information in the thread in some cases and that pisses me off :mad: .
This thread wasn't started with me intending to build an intake with valves or an exhaust with variable back pressure but I may well do both in the end. Someone else may decide they want to tinker in this direction and may do something some of us are interested in and can learn from.
I'm still interested in hearing from people who have something relevant to say in this area. Keep it coming, this thread has been pretty fun! I reject the reality ram rodded by some people and proselytize my own version of reality ( which I happen to think is closer to being real or true). :)
Regards, Michael

This:
http://img328.imageshack.us/img328/2880/wilsonpw7.jpg

...seems remarkably similar to this:
http://i51.photobucket.com/albums/f400/topenlt1/lt5c.jpg

Now what I'd be curious to see is a cutaway picture of an LT5 intake and see if the runners protrude into the intake plenum at all like the first rendering. Does anybody happen to know off hand what the runner length on an LT5 intake is?

I'm no airflow expert, but my gut instinct tells me that the CAD drawn intake might have turbulence issues.

(And yes, before anyone decides to throw flame darts I realize that an LT5 intake doesn't fit an LT1.)

This:
http://img328.imageshack.us/img328/2880/wilsonpw7.jpg

...seems remarkably similar to this:
http://i51.photobucket.com/albums/f400/topenlt1/lt5c.jpg

Now what I'd be curious to see is a cutaway picture of an LT5 intake and see if the runners protrude into the intake plenum at all like the first rendering. Does anybody happen to know off hand what the runner length on an LT5 intake is?

I'm no airflow expert, but my gut instinct tells me that the CAD drawn intake might have turbulence issues.

(And yes, before anyone decides to throw flame darts I realize that an LT5 intake doesn't fit an LT1.)


Well thats a Wilson design and he don't design thing that don't work and sell them.
He IS the master whether it's F-1.Indy Car or Pro Stock he IS the master.

A 4.6 intake is like that on the inside and they work,sometimes TOO good.

Why 1racerdude thanks for the interesting graphical display you setup there. I'm not sure on the runner length on the LT5 motor. I think I've read that the LS1 runners are close to 15" long vs. around 21" for the TPI intakes. The plenum is certainly wide enough for the runners to extend in their a ways. Anybody have a link to a cutaway of the LT5 manifold?

A couple of you dummies are stinking up this thread. If you have a problem with people discussing advanced tech stuff like exhaust valves and variable resonance intakes then maybe you shouldn't be in this area.

.
The next time you call people dummies, and flame people, your posting privilages are going to be affected. The agreement you read when you signed up said you would not engage in flaming.

The LS1 has 8inch runners I believe, the Accel Super Ram has 15inchs or runner length and most SBC Single planes have 5-6inch runners.

Well thats a Wilson design and he don't design thing that don't work and sell them.
He IS the master whether it's F-1.Indy Car or Pro Stock he IS the master.

A 4.6 intake is like that on the inside and they work,sometimes TOO good.

Do you know if they plan on producing this intake?

Do you know if they plan on producing this intake?

Call them and talk to Ted he will know.

Do you know if they plan on producing this intake?

The LS1 intake is being produced now.


The LT1 intake posted in this thread.....no.



David

I read a few tests on the TPI vs HSR vs Single plane, and the torque output from the modified TPI is shocking.....but as every one knows the long runners die at about 5600. Big runners, ported base and 21" runners make 30 ftlbs more that a superram, and a superram makes about 30ftlbs more than an lt1 intake. If you could somehow have short ram tubes controlled with a butterfly valve to the plenuum to bypass the long runners at 5500 rpm(use a window switch). Just a pipe dream for my resources...but food for thought.....
It looks like a dual plane manifold is very close to the best all around compromise up to 6500 rpm, really good torque and very little drop off; however I heard there were problems with a dual plane and port injection....not sure why. I would love to use a RPM air gap with an elbow but the super victor or HSR is more economical( I have hood clearance). I was hoping that an HSR(holley stealth ram) would match the RPM airgap in torque(both have about 6" runners I think) but it looks like the rpm beats it till about 6100 rpm. Now I have not seen a direct HSR vs RPM vs LT1 vs Super victor... that would be a nice test.....

Car craft on their web site has a test on ported vortec heads. They switch between a RPM and a Super victor.... the Victor gets smoked up to 6500 RPM where the engine quits making power 350ci 235/235 lunati cam.

The LS1 intake is being produced now.


The LT1 intake posted in this thread.....no.



David

That's not an LT1 intake anyway, the runners are spaced for the LS1.

That's not an LT1 intake anyway, the runners are spaced for the LS1.


I was referring to the LT1 wilson manifold that is ours pictured on the 1st page.


It will not be produced, it is a one off deal


David

I was referring to the LT1 wilson manifold that is ours pictured on the 1st page.


It will not be produced, it is a one off deal


David

Gotcha. It's a shame though, that looks like a good performer.

Car craft on their web site has a test on ported vortec heads. They switch between a RPM and a Super victor.... the Victor gets smoked up to 6500 RPM where the engine quits making power 350ci 235/235 lunati cam.

a better comparison on that test might have been an RPM air gap vs a victor jr and then a torker thrown in the mix just to see what happens. only time i see anyone with a torker these days is pontiac swaps into third gens so they clear the stock hood.

edit: they don't make a vic jr for vortec heads, do they?

CrystalSS, I've been thinking along the exact same lines you outlined in your most recent post. The potential powerband width using a well designed dual length runner setup could be awesome for a street car. I once installed a completely stock TPI setup with an electromotive ECM on a very hot 383 ( aftermarket heads, big roller cam and very high compression as it ran off aviation fuel). It produced super midrange for such a large cam/head package but completely choked out in the mid 4k RPM range. The long and "skinny" TPI runners made a load of midrange even with a large, lopey cam. But no topend to speak of, tried to warn him.
I suspect that if you had the flexibility of going with dual runners that the width of the torque peak of the different runner lengths would allow more specialization in the selection of the runner dimensions. Using a set of really long runners ( TPI style) combined with a really short set ( LT1 style) that were optimized might make for a crossover point closer to 4500 or 5000 RPM's. Just speculating as I haven't put a lot of thought into it but based on my experience the longer runners might produce more midrange and lowend if they were a shade smaller cross sectional diameter than the biggest aftermarket TPI stuff ( that stuff may be compromising some low end for reasonable top end). You might wind up in a situation where the overlapping torque peaks of the two different runners would allow greater tuning specialization of the long ones so they were optimized more for mid/low with little thought of higher RPM effectiveness. It would certainly be worth researching to see if it might be more effective to have a smaller diameter "tube" for the bulk of the long runner that Y'ed into a larger diameter short runner just upstream of the injector. Just a thought.
The more I think about this the more I think I'll build one.
Anybody else have any educated guesses on how they'd setup the runners in such a gizmo?

I never thought I would be posting about a TPI article on here but the info on the HSR and the Single plane are interesting.
http://www.compcams.com/Community/Articles/Details.asp?ID=1737510521
Another good one:
http://www.compcams.com/Community/Articles/Details.asp?ID=-61543841
Its all old news but worth reading......

Free your mind.

. . .I heard there were problems with a dual plane and port injection....not sure why.

Air distribution. There are drastic differences between the port flow of the low (bottom plane) entry runners and the high (top plane) entry runners - as much as 30 cfm. With a carb, the fuel stays with the air, so the cylinders that are starved of air are also starved of fuel. With port injection, you give all the cylinders the same amount of fuel, so 4 run rich and 4 run lean.

It's nice to talk about theory of dual runner intake manifolds, but the fact of the matter is that a well-designed intake manifold for a 2-valve motor doesn't need 2 lengths of runners. A well designed intake manifold (LSx) has medium length runners with no kinks, smooth surface finish, and a fair amount of taper. You basically get the torque advantage of the length, with alot of flow from the size and finish, plus the added benefits of taper. I think you would be hard-pressed to top a LSx intake manifold with a dual-runner/valve intake.

All this is a moot point, though. Only 1 in 1000 people who say they are fabricating an LT1 intake will actually do it. I bet no one ever builds a dual-runner/valve intake, so discussing it is really wasting time. I would be VERY interested in seeing an LSx style LT1 intake, though. It would work well, assuming it's designed right, and it might actually happen.

Mike

Air distribution. There are drastic differences between the port flow of the low (bottom plane) entry runners and the high (top plane) entry runners - as much as 30 cfm. With a carb, the fuel stays with the air, so the cylinders that are starved of air are also starved of fuel. With port injection, you give all the cylinders the same amount of fuel, so 4 run rich and 4 run lean.

Mike,
If ya ran the Hilborn set up that goes direct into the chamber right next to the plug the fuel would be the same. Then anything coming from above would be air only.
Have used there in sprint cars a few years back but they had maintenance problems 'cause the nozzles needed maint EVERY time they were run. The old nozzles in the intake worked as good.

Well i'm going out to the garage right now, picking up my air tools and fabricating a new LT1 intake!!!!:metal:

Right after I finish my twin-turbo, over-head cammed, variable timing 355.....

But seriously, I agree with engineermike. The LSx style intake seems to work well and you don't have any of the hood clearance issues. Obviously you would have to redesign it to fit the port pattern on LTx heads. Maybe someone with knowledge of plastics casting could manufacture a composite intake?

Well i'm going out to the garage right now, picking up my air tools and fabricating a new LT1 intake!!!!:metal:

Right after I finish my twin-turbo, over-head cammed, variable timing 355.....

But seriously, I agree with engineermike. The LSx style intake seems to work well and you don't have any of the hood clearance issues. Obviously you would have to redesign it to fit the port pattern on LTx heads. Maybe someone with knowledge of plastics casting could manufacture a composite intake?


Come on, I want pictures:bow:

The LS1 manifold is an interesting hybrid of the TPI and LT1 stuff and is cleverly packaged to get good runner length in a small size, that's what made it interesting to me from a design standpoint . As far as the basic LS1 design being optimal, many people seem to think the LT1 motor has more low end punch than the LS1. If that's true it might owe to the fact that the LS1 runners while longer are also a lot bigger diameter which would negate some of the charge tuning at lower RPM's. I'm not convinced that the LS1 intake is so well designed that dual stage intakes offer no clear advantages. Having driven them they were much less engaging in the lower/mid range than the old TPI cars even though their cylinder heads are much more advanced. For the most part it seems that one moderate length runner is a workable compromise that gets the job done for a reasonable price. With available technology could a setup be constructed that would ram the charge past the intake valve much better than an LS1 at lower RPM's while still having superior top end pull too? I believe. I believe

Help me up, I've fallen and can't see. I was blinded by a bright light!.

grammarman, I invite you to build one then. Please.

And BTW, the LS1 isn't the first engine to use that style of runners and plenum beneath it. I've seen it on foreign V-8's, even domestic V-6's for many years. In fact, the Dodge 318/360 is the same layout. It just makes sense on V engines with limited hood clearance.

Mike

I have a question... Supposing, that I want to go with a professionally built sheet metal intake from Hogans or Wilson. What all information is necessary to provide them to build the best designed intake for my setup?? Obviously designing an intake is a very complicated process, and probably should be left to professionals with several years of experience in the area. So is getting the best sheet metal intake as simple as a phone call away? - by providing information such as: I have an 381 LT1 with GM LT4 heads which flow XXX, and these are the cam specs XX ? or do you need to provide more detailed specs that you want to have the intake built to?? such as what volume that you want it to be, and what length you *think* the runners should be, and etc. ?

I'm sure the people at Wilson or Hogan will be able to give you some expert advice based on the engine you have. Most importantly based off of the cam/heads combo and your goals for the project. I'm sure it would be easier if you already knew the plenum volume and runner length desired, but I'd rather let the experts figure it out.

Jeremy

a really well built sheetmetal intake will require the block and heads to be present.

Just watching :)

Found these:

http://users.bigpond.net.au/southways/020703b_C5R_01201.jpg
http://users.bigpond.net.au/southways/020703c_C5R_01202.jpg
http://users.bigpond.net.au/southways/020703d_C5R_01203.jpg
http://users.bigpond.net.au/southways/020703e_C5R_01204.jpg
http://users.bigpond.net.au/southways/020703f_C5R_01205.jpg
http://users.bigpond.net.au/southways/020703g_C5R_01212.jpg
http://users.bigpond.net.au/southways/020703h_C5R_01213.jpg
http://users.bigpond.net.au/southways/020703i_C5R_01214.jpg
http://users.bigpond.net.au/southways/020703j_C5R_01215.jpg

It's apparently a C5R intake built by Harrop. I can't even begin to fathom what tuning something like this must be like.

It's apparently a C5R intake built by Harrop. I can't even begin to fathom what tuning something like this must be like.

It looks like it might tune itself...probably should for what someone might pay for it. Either way it appears to have adjustable valves in the runners, what do you think about that 1racerdude?;)

That's actually not adjustable runners - that's the throttle blades.

That intake is off the C5R Compuware racecar, It has a box that goes over it. If I am not mistaken.


David

That's actually not adjustable runners - that's the throttle blades.

My mistake:shame:

Why put the throttle blades that far down in the runner though? Does it help with velocity?

My mistake:shame:

Why put the throttle blades that far down in the runner though? Does it help with velocity?

Just like a set of Hilborn mech fuel injection.

Why put the throttle blades that far down in the runner though?

My guess is that it's for instantaneous throttle response. Very short distance and volume between the throttle blade and the cylinder translate into lightning quick response.

I once had a Dakota RT with the 360 Magnum in it. :shame: Those engines have huge, barrel shaped plenums and long runners. You could time throttle response with a sun dial.

My guess is that it's for instantaneous throttle response. Very short distance and volume between the throttle blade and the cylinder translate into lightning quick response.

I once had a Dakota RT with the 360 Magnum in it. :shame: Those engines have huge, barrel shaped plenums and long runners. You could time throttle response with a sun dial.

That's what I thought. Yet again, why doesn't someone build something like that for the LT1? Stupid outdated engine....:(

OK, I've been doing lot's of sketching and calculating on the low and high rpm runner lengths along with chasing down dyno graphs for various intakes (from TPI to miniram and everything in between). Thought of going with a aftermarket TPI system and then connecting shorter runners between the bottom of the plenum and the base, from the calculations for tuned runner length ( 84,000 divided by peak power RPM equals runner length in inches) it looked like this would work pretty darn well. The TPI runner length is about 25" including 6" from the intake surface on the head to the head of the valve. The shorter runner length could be around 15" ( also including the intake port in the head) for a peak around 5500 RPM's and good overrev to 6500 or so. You'd get the typical 35 to 50 ft. lb. torque hump from the TPI length runners around 3K to 4.5K and the shorter runners would come in and optimize the resonant tuning for a very good top end.

Problem is that a stock TPI is about 2 inches too high to fit under the 4th gen F-body windshield cowl. Looks like it would have to use custom runners/plenum to get somewhere around TPI'ish runner lengths (actually would like several more inches than the TPI) and clear the cowl. A simplified description of a workable solution may be to use a LT1 TPI base from Accel and then cut a set of big tube runners in half and turn the upper half 180 degrees so they point out over the heads. For it to work they would have to be cut in at two places and just use about 45 degrees of the radius on each end connected be straight tubing ( to lower the overall height). Then build a plenum, fab the butterflies into the base manifold and connect shorter runners to bottom side
of the plenum.

A considerable amount of mill, welding, layout time would be required so due to time constraints I will probably put the LT1 intake back on right away and tune it/dyno it, and also run some 1/8 mile runs at 1/8 and 1/4 throttle as well as WOT. Then if I get the variable intake built just swap it on one weekend and retune/retest for a valid comparison. The part throttle track runs have delivered some interesting results in the past and I think they give you a more complete picture of how stout an engine feels during average daily driving.

Regards, Michael

Sounds like a good plan.

How about a dual plenum intake? Imagine 2 cylindrical plenums, one over each row of intake ports, with short runners to each port. Then long runners to each port on the opposing side, connecting to the short runners in a y-joint. When you are at low RPM the plenums supply air to the heads on the opposing bank via the longer, diagonal runners. When you hit the high band a "trap-door" opens the short runners while sealing off the long ones.

Might work, I'll see what I can do with AutoCad as a rough demonstration for anyone who can't visualize this.

Jeremy

I think a stock TPI will fit under a 4th gen cowl, Accel Super Ram will, see the pic on the first page of this post, our intake fits, but it does touch underneath. It is WAY taller than a stock TPI setup.


FOr sure its not 2 inches too high.


David

According to Lingenfelter the Super Ram will not clear and uses a different plenum part number for the 4th gen F-body that is shorter by 5/8" compared to the stock Super Ram. I don't have a TPI in hand but came up with what I figured should be a close approximation of the height by scaling a side photo of one I found by the center to center distance on the injectors. I doubt anyone likely see this has a complete TPI sitting around they can measure so I'll check my numbers again and do some more reasearch. Would certainly save a lot of work if a TPI will fit.

Jeremy, you said:

How about a dual plenum intake? Imagine 2 cylindrical plenums, one over each row of intake ports, with short runners to each port. Then long runners to each port on the opposing side, connecting to the short runners in a y-joint. When you are at low RPM the plenums supply air to the heads on the opposing bank via the longer, diagonal runners. When you hit the high band a "trap-door" opens the short runners while sealing off the long ones.

If you play with any drawings I'm looking at something like 15" and 25 to 30" for total runner lengths. Subtract 6" for the intake port portion of the runner length. To get 9" of actual intake runner for the short ones I think the height limitation is going to require a crossing/angled approach coming from nearer the center of the intake. I'm interested in any ideas you have for layout with runner lengths in those ballparks.

Later, Michael

I have a TPI on my car with SLP runners. I will measure from the bottom of the base to the top of the plenum. Well with a ruler at an angle and a ballpark figure I would say a minimum of 8" tall and probably 8 1/4" tall. I can bend something up for a more accurate measurement if you need it.

By the way I'm doing what you are trying to do but comming at it from the L98 TPI end of things. I have completely hogged out my SLP runners so that the actual runners start at the intake manifold. So figure 6" for the head and 6" for the manifold that puts my total runner length around 12".

I'm right now I'm building up another long block with all the goodies including ported 200cc heads and an XFI cam and will use my highly modified TPI system on it. Here is a link to my runners and plenum.
http://www.thirdgen.org/techboard/attachments/tpi/88764d1109706323-highly-modified-tpi-c-documents-settings-owner

By the way I have considered doing some sheetmetal runners. Will just have to see what my latest combo comes up with. Right now I'm at 330RWHP and 370WTQ with an A4. Hoping to bump that up quite abit with the next go around.

I can understand where you are comming from as I like to experiment myself. Good Luck.

This project will never happen. . . too complicated, too difficult to fabricate, too many things to go wrong, . . . It would be hard enough to simply fabricate a functional LS1 style intake for the LT1, let alone dual runners and electronic valves.

Seriously, the small gains this will get is not worth the amount of effort it's going to entail. You'd be better off putting in a stroker crank and a Victor EFI intake. It will have more torque and hp than stock stroke and intake throughout the range. It will probably have more torque than a TPI down low also.

How, exactly, will you know you're at 25% throttle for the dragstrip runs anyway?

Man, that Victor EFI sure looks sweet sitting on my motor. . .

FYI, there's about 4.5" of space between the carb flange and the cowl.

Mike

Here is a rough idea of what i'm talking about. There are obvious improvements to be made, this is just to get my point across.
http://i84.photobucket.com/albums/k6/Jerminator96/intakerender.jpg
There would be butterflies in the runners flush with the inside of the plenum. The long runners would be open in the low range, and short in the high revvs. I included one runner with an arc to show how more length could be obtained.

I'll keep working on the design till I get something I like.

Jeremy

Edit: I think I could control the butterflies on one long shaft running through the plenum, actuate it in the rear with a electric cutout motor, and controlled by a window switch. Might not be the simplest design, but it is made of materials readily available.

I'm thinking Billet :cool:
Machine all the parts and have it welded to gather.
It would be more like one from Nelsons Racing but it would be better than what we have now.
Just have to figure out how to do the PVC Valve and a few Vacume lines.

I drew (rather hastily in paint!) a dual runner system based off the tpi intake a few years ago. Though never having seen a tpi intake in the flesh I'm not sure if such mods would be possible

http://img518.imageshack.us/img518/8403/dualrunnertpiau2.th.jpg (http://img518.imageshack.us/my.php?image=dualrunnertpiau2.jpg)

That looks great in theory, but getting it all to fit with the center runners next to each other is going to prove to be a big problem.

I'm thinking Billet :cool:
Machine all the parts and have it welded to gather.
It would be more like one from Nelsons Racing but it would be better than what we have now.
Just have to figure out how to do the PVC Valve and a few Vacume lines.

I was thinking sheet metal, I'm not sure that I could get the equipment (or budget) to do all billet parts. It would be cool though.

That looks great in theory, but getting it all to fit with the center runners next to each other is going to prove to be a big problem.

Are you talking about my drawing or the TPI? Obviously my drawing is based on LS1 heads (for simplicity) though I know it's an obvious sacrifice in hood clearance compared to the stock design.

I do believe, however, that it could be made to work with the LT1 port pattern. I'll try tonight, might even add flanges and re-draw it to a proper scale (current drawing has 16" plenums, 4" in diameter).

Jeremy

Hey engineermike, you now have multiple posts saying it's not practical, it's a waste of time, it will never happen. We get your point. From your posts one would think that you aren't interested in such a project but the posts keep coming. Why not just lurk or add something constructive?

50 ft. lbs at 3000 RPM's is not what I'd call a small gain when you can do it and still have a manifold that is optimized for high RPM peak power too. I believe the gains at part throttle are even more impressive as a percentage because the intake tract sees lots of vaccum. The charge inertia and resonance tuning combine to help cram much more air in there under light load. If you think there are too many things to go wrong then maybe you haven't fab'ed many projects of this complexity level. I have. You have to visualize everything down to the last detail and put it on paper, then the inevitable things you didn't think of are generally manageable. Experience helps a lot here. I Already have a stroker crank going in so that suggestion is covered. As for the victor EFI intake, I'm looking into lengthening the TPI runners by around 5 inches which will reduce the tuning RPM range by about 500 RPM's. With a mild 2400 to 2800 RPM stall converter the difference in lowend between the VIC and TPI would be hard to feel unless the converter clutch is locked ( light throttle cruise).

The way I've known I was at 25% throttle in the past was to rig a stop on the throttle linkage and read the TPS voltage to set it. Press the throttle until you hit the stop and voila, you're at 25% throttle every time.

Gus, your sketch looks very much like the one I'd worked out on the TPI system. I have a butterfly valve at the bottom end of the short runner where it ties into the top of the long runner in the base manifold. If I can work out the height so it will fit I think this is the most time effective way to do it.

Jeremy, your sketch is nice. I think the height limitation in this application would make your design difficult to get a 9" long runner for the short one. Ideally the short runner would also be angled in so the air wouldn't have to make a 90 degree turn. To get 9 inches from the plenum to the head on the short runners I think an angled approach is going to be required.

Jeremy, your sketch is nice. I think the height limitation in this application would make your design difficult to get a 9" long runner for the short one. Ideally the short runner would also be angled in so the air wouldn't have to make a 90 degree turn. To get 9 inches from the plenum to the head on the short tunners I think an angled approach is going to be required.

I have that worked out already, when I get time I'll post a revised model.

Cool, one other thing. The arc idea to increase length is good as long as you wind up with a straight shot down the intake port in the head for the last several inches of the runner. I'm leaving for Panama City Beach for the weekend and may be offline. Hope to find some creative ideas when I'm able to return.

Regards, Michael

Ah, thats where I have the upper hand :D
I work in Tool & Die and have more 3/8 1/2 & 1.00 plate laying around along with Large chunks of Billet that are free for the taking :cool:
I have 2 chunks in my tool box right now that I could build 2 CNC valve covers with no problem.

When I saw the Intake from Nelsons Racing I was like I could build that and weld it togather with out a problem.
Now all I need is a blueprint to follow and I'll be all set, time to get back to the drawing board.

Ah, thats where I have the upper hand :D
I work in Tool & Die and have more 3/8 1/2 & 1.00 plate laying around along with Large chunks of Billet that are free for the taking :cool:
I have 2 chunks in my tool box right now that I could build 2 CNC valve covers with no problem.

When I saw the Intake from Nelsons Racing I was like I could build that and weld it togather with out a problem.
Now all I need is a blueprint to follow and I'll be all set, time to get back to the drawing board.

Well I can draw up a blueprint along with a 3-D model for you, I'd just need some measurements. How about in exchange for a set of intake flanges with a lifter valley cover?:D

I'll see??
I can't promise anything but if you want to make a print I will need the following:
Top view
Front view
Side view of each piece seperate and as an assembly.
I will need a center line of each port.
Distance from Front & Outside edge to each port.
Finish size of ports
Angle's
How much do you know about drafting?

I can't do the long runner LSx style, it would be more of a Mini Ram style.

But send me wat your thinking and I will look at it:
morepower2ya@comcast.net

This is where I work: http://www.paragondie.com/

Here is the revised LT1 port manifold design.
http://i84.photobucket.com/albums/k6/Jerminator96/intakerender2.jpg
http://i84.photobucket.com/albums/k6/Jerminator96/intakerender3.jpg

Obviously still just a rough mock up. The major problem I foresee is that it is actually 21" wide in the drawing. To make it shorter I will need to shorten the long runners considerably and run them from higher on the plenum with more arc then another bend back towards the ports (more then I wanted to do tonight). I'd also like to shorten the shorter runners a little.
I also have no idea how I want to do the merge from tube to rectangular ports, maybe it wont be for the LT1 after all.

Still, I think the design would work. It wouldn't give you much more torque down low (LT1 comparison) But I think the high revvs would benefit alot.

Jeremy

I'll see??
I can't promise anything but if you want to make a print I will need the following:
Top view
Front view
Side view of each piece seperate and as an assembly.
I will need a center line of each port.
Distance from Front & Outside edge to each port.
Finish size of ports
Angle's
How much do you know about drafting?

I can't do the long runner LSx style, it would be more of a Mini Ram style.

But send me wat your thinking and I will look at it:
morepower2ya@comcast.net

This is where I work: http://www.paragondie.com/

I can't seem to find that Nelson Intake you are talking about. Do you have a link to some pictures? I'd need some detailed measurements to draft a print or the manifold itself, unless you wanted to do it custom and just give me general dimensions with specific runner lengths/port sizes.

I wouldn't do the LS1 style, i'm not into those motors yet. Anything that would fit a standard SBC would work, maybe LT1.

I'm a fairly skilled draftsman, time is the only issue. I tend to stay pretty busy with work (mortgage broker) and this is really only a hobby. I could probably cut an LT1 intake up and use the flanges as a base, but billet would be much cooler.:D

Jeremy

4th vid down called project F-Bomb:
http://www.nelsonracingengines.com/vids.html
3500.00 Intake :eek:

This is the curent mag on sale now:
http://www.hotrod.com/toc/thismonth/

There are pics of motors with the Intake on in cluding the F-Bomb motor:
http://www.nelsonracingengines.com/motors.html

The Base and flanges you want are they going to mock the LT-1 Intake?
Get me some specks?

I have been thinking about the intake also.
Have you ever seen the Banks system for there Turbos, Twin intakes, one for each side of the motor.
Kind of like the Vipper V10 with twin TB's.
I have an Idea but I need to get my spare motor back so I can get some dimensions but it would be a double TB setup?

I have been thinking about the intake also.
Have you ever seen the Banks system for there Turbos, Twin intakes, one for each side of the motor.
Kind of like the Vipper V10 with twin TB's.
I have an Idea but I need to get my spare motor back so I can get some dimensions but it would be a double TB setup?

Yeah that's kind of what I'm going for with mine, just the long runners cross.

I'm not sure yet whether I should go with LT1 or SBC, but probably LT1. So the base and flanges will have to fit onto an LT1 block, no need for distributor hole, and obviously it will have to mate to the heads.

You should try using PVC Pipe to fab it with before you do a Alum fab job that way you get every thing right for way less money.

You should try using PVC Pipe to fab it with before you do a Alum fab job that way you get every thing right for way less money.

I'm not sure if i can get PVC that is flexible enough. I might just use cheap mild steel exhaust piping. My uncle owns an exhaust shop so I can use his pipe bender to get everything fit right.

50 ft. lbs at 3000 RPM's is not what I'd call a small gain when you can do it and still have a manifold that is optimized for high RPM peak power too. I believe the gains at part throttle are even more impressive as a percentage because the intake tract sees lots of vaccum. The charge inertia and resonance tuning combine to help cram much more air in there under light load. If you think there are too many things to go wrong then maybe you haven't fab'ed many projects of this complexity level. I have. You have to visualize everything down to the last detail and put it on paper, then the things inevitable things you didn't think of are generally manageable. Experience helps a lot here. I Already have a stroker crank going in so that suggestion is covered.

.

Being I’m the only one apparently on the list who actually owns an intake manifold with six inch runners, may be able to transfer how the car responded going from a very heavily welded and reported/raised port LT4 intake:

True it picked up 47ft lbs of torque 3000 rpm but the throttle response is also much quicker. There was an off idle hesitation that has completely cleared itself up. After programming it usually takes at least a couple of tanks of gas for the computer to relearn how to idle. With this intake it cleared up perfectly after about a half a tank of gas.

The car also seems to run smoother overall and for sure you feel the extra torque especially in the higher gears. Say for example a light turn yellow and I’m cruising in 4th gear @ 35mph. Very surprised how much quicker the car picks up speed in higher gears and lower rpm. Do I notice it in first gear? Na….spun the tires before and spins them now.

As far as the loss above 6100 goes: After a couple of months of internalizing and looking at the dyno sheets, the intake did exactly what you would expect a more efficient intake with longer intake runners would do. Shift peak power downward and increase low end.

It did that all right greatly adding power in the lower range. All I need to do now is correct the powerband with the proper cam so that it peaks in the 66-6800 rpm range. and I’m positive the bottom end will be stronger than before and it will also pick up on top because the manifold overall is more efficient. Just a matter of adjusting to the overall change in powerband.

Think you’ll see the car close (if not making over 500 rwhp) in the next couple of months and I’m not sure how many people can say that from a standard 23 degree head, hydraulic cam LTX car.

Would I do it again?............Damn right. Now those expensive stepped headers with reducer merge collectors?? Not so sure about that one.

Pics?

Hey Denny, that is a great post. Very good information man, very much appreciated. Now according to the Chrysler patent on ram tuning intake runners from way back when your 6" runners plus about 6" of intake port to the valve head should produce a peak centered around about 7000 RPM's. I've seen quite a few dynos on various tuned runner intakes and the Chrysler formula ( 84000 divided by runner length from plenum to the head of the valve equals peak RPM point) is usually in the ballpark. Did you enlarge the cross sectional area of the LT1 manifold? It might take a little more CSA to really let the 6" runner produce full peak HP potential on a hot smallblock though at the loss of some low/mid and throttle response.

The Viper engine uses a pair of single butterfly throttlebodies ( or at least the one I did an engine conversion with did anyway). If I remember right they use a crossover cable to actuate the second one and sync it with the primary that the throttle cable connects to. Usually when I'm working on something this complicated I spend a LOT of time on paper. You need accurate dimensions on your space you have to work with and then detail everything with center to center dimensions, angles, ID, OD, height, width, length and any other dimension you can think of, helps to use a graphics program and do everthing to scale. You need to work out all the details so they appear to work in side views, top views and end views. Even after all that you just can't hardly think of everything but it sure beats hacking the same parts off five times to try to make things work. :)

Later, Michael

Pics?

There are some picturers of the intake way earlier in this string. Can't believe how long this thing got.

Hey Denny, that is a great post. Very good information man, very much appreciated. Now according to the Chrysler patent on ram tuning intake runners from way back when your 6" runners plus about 6" of intake port to the valve head should produce a peak centered around about 7000 RPM's. I've seen quite a few dynos on various tuned runner intakes and the Chrysler formula ( 84000 divided by runner length from plenum to the head of the valve equals peak RPM point) is usually in the ballpark. Did you enlarge the cross sectional area of the LT1 manifold? It might take a little more CSA to really let the 6" runner produce full peak HP potential on a hot smallblock though at the loss of some low/mid and throttle response.
:)

Later, Michael

The cross sectional is a bit larger (wider) than a LT4 raised port off road gasket. I gasket matched it to this gasket (same as the heads) and had to do some epoxy fill blending about a couple of inches just before it reaches the heads. Didn't bother to measure but I'd guess about .200 inch of taper. Have picturers but not sure if the detail is enough for anyone to tell.

Again, still playing with the combo and it's been so frickin hot here in Dallas that the first cam I'm going to try is still sitting in the box in the car. If it every gets below a 100, just might give it a shot and see what it does. It will get worked out but when you don't have a known variables to work with your the test monkey shot off into space.

Well after doing some calculations, I just don't think I can get my design to work with the rectangle ports and my given amount of space. I maybe could get it to work with oval ports but the transition wouldn't be great for airflow.

However, the VH45 heads that I may purchase for my DOHC SBC project have concentric circular intake ports, a prime candidate for this design.

Denny dose that intake run flat all the way accross the bottom?

I like to hear the story on the exhaust vacuum bungs to the valve cover

Let's say it was a $2,000.00 lesson on diving into the pool w/o checking how deep the water is taking someone's word on it. We picked up nothing. Yep, CNC ports, 1 3/4th to 1 7/8th to a 3" Burns style merge collector with 2 1/2 reducer. And the dyno said zippo!

Haven't given up completely on the headers as couple hardcore racers I know say they are the real deal but the cam needs to be changed to get the most out of the headers.

Already got a couple of cams that we'll try and still doing some research but everything is on hold till the weather gets better. It was 107 here in Dallas with everyday over 100 degrees and orange polution alerts. Not exactly home run tuning weather.

Now you should hear the story about the exhaust vacuum bungs and hooking them up to the valve covers.

^ :yes:

Denny dose that intake run flat all the way accross the bottom?

The intake is flat on the bottom. Actually thought of having it thermo coated but ended up not doing it.

I like to hear the story on the exhaust vacuum bungs to the valve cover

Did those the same time as the intake hoping to pick up a little more power through better ring sealing and should have waited to do it separately. Don't have a baseline to make any intelligent comments. The guys using vacuum pumps claim they pick up 10-15 hp on top but I have doubts that much is really going on. Should be some vacuum caused by venturi effect but I need to play with that a little to see if it drawing much at all.

Kinda like the expensive headers........good idea at the time. Haven't completely given up on the headers as someone told me you needed to change the cam split to take advantage of them but I haven't been able to substantiate that either.

Again, ya ain't gonna make any yards if ya don't carry the ball. Just trying to do my best at figuring out this stuff.

Again, ya ain't gonna make any yards if ya don't carry the ball. Just trying to do my best at figuring out this stuff.

You seems to be doing a good job of that. The rest of us (with less money) will let you do all the expensive research;) Just tell us how it works out.


Jeremy

You seems to be doing a good job of that. The rest of us (with less money) will let you do all the expensive research;) Just tell us how it works out.


Jeremy

I've got the guts........somehow I seem to be missing the glory. It would be nice to hit a couple good balls instead of clobering dirt.

I've got the guts........somehow I seem to be missing the glory. It would be nice to hit a couple good balls instead of clobering dirt.

Hey I'll be right there with you if this DOHC project gets off the ground. Then maybe we can trade secrets that don't work in hopes of success on a different motor.:think:

Jeremy

If any of you have personal problems with each other here I'd appreciate it if you took it to PMs or better yet, to email.

I don't want to have to say this again in this thread, thanks. :)

Hey Mr. Moderator, while your at it I'd appreciate it if you'd delete the posts that have polluted this thread with arguments that have nothing to do with the topic. Can't hurt to ask, can it? :rolleyes:

I saw this going bad... a shame that one individual has to wander off the tech issues and start calling people names. I hate to waste my time culling old posts, but this forces me to do it. It amazes me that its taken this long for people like Bret and Denny to respond..... they seem to be able to stick to the tech issues, without turning it into a personal attack.... but after a while, I can understand their need to respond.

There are valuable members who don't come here as much any more because of stuff like this.

Well I have been doing some mesurements and I have figured out that I can Raise the top of the Intake 2 3/4 inches and still have enough clearance.

I'm going to start a Long Hand Drafting of what I think would work and then fab it up.
SHould look like Denny's when I get done :)

Well I have been doing some mesurements and I have figured out that I can Raise the top of the Intake 2 3/4 inches and still have enough clearance.

I'm going to start a Long Hand Drafting of what I think would work and then fab it up.
SHould look like Denny's when I get done :)

When I first saw the intake it looked like a leap of faith for it to fit. Much to my surprise there is all kinds of clearance. You might have more room than you think as I was a bit nervous.

We did the very scientific measurement of crushing a beer can to see how much clearance there would be.

Will see what happens with a couple of cams and make a judgement then, but right now I'm thinking a little bit shorter on the runners might not be all that bad of a thing. All live and learn.

I called Wilson and gave them the complete engine spec's (the intake was not done by them) and they custom tune it to your combination so it would probably vary per the application.

We did the very scientific measurement of crushing a beer can to see how much clearance there would be.

:lol:

It's a pretty good idea, though. Tell me you measured can height with a micrometer afterwards?

When I first saw the intake it looked like a leap of faith for it to fit. Much to my surprise there is all kinds of clearance. You might have more room than you think as I was a bit nervous.

We did the very scientific measurement of crushing a beer can to see how much clearance there would be.

:lol: I like it!
I have a few more measurements to take yet but I have the general Idea.
I could raise the back about 1 inch more but I don't want it to get too close to the windshield :D

My main plan is to incresse the Volume so I can add some serious HP to my Stroker Motor and not be confined to the LT-1 intake.
My new cam right now has 108* LS with .565 lift and 226/234 for Duration so I will be trying to match for that cam and Bigger :D :D

I found a local guy that is very very good at welding and is willing to weld up an intake or two or four etc. His prices are pretty reasonable as well. I'm not going to pass up the opportunity.

My question is this...

I have LE2 heads that flow 291 cfm and a lumpy LE2 cam. What style intake would work best with these heads and at the same time allow me to step up to say a 210 or 220cc head if I want in the future? Or is this not possible?

Anything else we should know design wise in regards to placement of injectors etc?

Would the cam fall on its face at higher rpm because of he intake?

He says this design is do-able:

http://img328.imageshack.us/img328/2880/wilsonpw7.jpg

But this one would be cheaper:

http://memimage.cardomain.net/member_images/10/web/454000-454999/454131_117_full.jpg

He's built several intakes and headers for turbo applications on import cars like his own 240Z and 280Z.

I would say stick with the second plenum if you have the hood clearance. It leaves more room for engine specific tuning. And you could always add more plenum volume or runner length later without too much work.

As for the cam, if it has a lot of duration then use shorter runners for the high end.

My $.02

Jeremy

As for the cam, if it has a lot of duration then use shorter runners for the high end.

I don't think that's totally true. Runner length as well as IVC affect rpm range. If you shorten a runner, then a motor will gain top end and lose mid-range. If you increase intake duration, resulting in a later IVC, then you will lose more mid and low, while increasing top end even further.

For example, an LS1 performance shop has a very popular, very aggresive LS1 cam. It peaks in the 6800 rpm range. They installed a Victor Jr. in place of the stock LS6 intake and the power was still climbing at 7600. The actually had to shorten the intake duration to get the power back down to a reasonable rpm.

Mike

Well the LE2 is similar in specs to the GM847 cam if that helps any.

I'm discussing designs with him as we speak and we're planning on doing it come October. But he's by no means a SBC expert so he's asking me to see what people recommend for this cam and heads for runner size, length, and injector positioning.

My question is this...

I have LE2 heads that flow 291 cfm and a lumpy LE2 cam. What style intake would work best with these heads and at the same time allow me to step up to say a 210 or 220cc head if I want in the future? Or is this not possible?

Anything else we should know design wise in regards to placement of injectors etc?

Would the cam fall on its face at higher rpm because of he intake?


But this one would be cheaper:

http://memimage.cardomain.net/member_images/10/web/454000-454999/454131_117_full.jpg



My cam is 245/248 with .630 lift and the heads are 222cc and guess it all depends upon high you want to take the car. Right now with this cam it peaks at 6100 rpm vs 6650 with a welded/ported LT4 and no other changes.

I rev to 6800 right now.

I don't think that's totally true. Runner length as well as IVC affect rpm range. If you shorten a runner, then a motor will gain top end and lose mid-range. If you increase intake duration, resulting in a later IVC, then you will lose more mid and low, while increasing top end even further.

For example, an LS1 performance shop has a very popular, very aggresive LS1 cam. It peaks in the 6800 rpm range. They installed a Victor Jr. in place of the stock LS6 intake and the power was still climbing at 7600. The actually had to shorten the intake duration to get the power back down to a reasonable rpm.

Mike

I agree entirely. However, if the cam choice is to remain the same, wouldn't it make sense to play to it's strengths? If that cam is similar to the 847, then it does well in the high rpm, so I wouldn't suggest putting on a manifold with long runners that would die at 6500rpm. Unless that is as high as he wanted to turn the motor, in which case get all the low-end and midrange you can.

Tell me if I'm wrong about any of this.

Jeremy

I rev to 6800 right now.

I take mine to 7000-7200 and looking to restore the same powerband. The car made over 470 rwhp @ 7000 rpm and also @ 6000 rpm peaking a little over 480 around 6650 with the LT4 intake so I want to be able to keep the average power as high as possible. We'll see what a couple of cams do and figure it out. Haven't done the math yet but I may not have lost average power by lowering the powerband because it pushed it up down below 6000 rpm.

It's not peak power that makes one fast, but average hp within intended powerband that does.

It's not peak power that makes one fast, but average hp within intended powerband that does.[/QUOTE]


I havent heard a MORE accurate statement in a long long time, this is why we do not race dyno's, this is why a lower peak horsepower car can kick your ass for you.

David

It's not peak power that makes one fast, but average hp within intended powerband that does.


I havent heard a MORE accurate statement in a long long time, this is why we do not race dyno's, this is why a lower peak horsepower car can kick your ass for you.

David[/QUOTE]

You have no idea of how many dyno sheets I've studied from professional builders/racers and everyone carries the power on top. Peak power is just for bragging rights.......powerband kicks butt. Right on Bro.

peaking a little over 480 around 6650 with the LT4 intake.

Is that a stock Intake that you are talking about?

Right now with this cam it peaks at 6100 rpm vs 6650 with a welded/ported LT4 and no other changes.

Do you have pics or is that the same one on pg #3?

Going with a longer runner to get a "ram tuning" effect in a 2K RPM or so window might work better depending on your RPM target. I wonder if the long winded Vic. Jr engineermike refers to is extending the topend because of an inertial effect that comes in late because of a large cross sectional area. The resonant tuning frequency of the Vic intake would also come in at a pretty high RPM level compared to the LS1 intake. The F1 stuff uses tuned runners to get max. VE in the intended operating range and technology is king there.

The Chrysler developed formula for intake runners came up a few pages ago. You can use it to calculate the runner length to optimize a particular RPM range. Simplified it is 84,000 divided by RPM target equals runner length ( including 6" for the intake port runner in the head to the valve head) . I have a link to a dyno test with several different length runners on a Hilborne injection system that bears out a sizable VE boost which corresponds with the runner length. Depending on your RPM target a Vic Jr might be great though, I don't know what the runner lengths are on those. I'll dig up the dyno page on the Hilborne setup and post it a little later.

Later, Michael

The Chrysler developed formula for intake runners came up a few pages ago. You can use it to calculate the runner length to optimize a particular RPM range. Simplified it is 84,000 divided by RPM target equals runner length ( including 6" for the intake port runner in the head to the valve head) .

Is the intake port on the head exactly 6"?

What rpm target should we be aiming for? Mid rpm band or peak?

Is that a stock Intake that you are talking about?

Do you have pics or is that the same one on pg #3?

The 480+ RWHP was with a ported LT4 intake. The car lost 6-7 hp peak on the top end and 20 @ 7000 rpm with the sheet metal one, but remember it gained almost 50 lbs RWT @ 3000 rpm.

When I say stock, never mean "stock" except in that it was the part GM provided on the car. Hell, not sure if there is a stock part left in the engine that wasn't tweaked somehow or replaced.

The “stock” intake was extensively welded on the outside to add more meat for porting to straighten the path into the heads. It was then sanded and repainted to look like nothing had happened. Guess I could take pictures of the LT4 intake ports, but it was gasket matched to the off road LT4 gasket.

Hand ported another LT4 intake going about as thin as I dared and it dynoed less across the board as compared to the intake with extra welding that did 480 rwhp. So welding and raising the port of the stock ones does help. Wasn't always sure of that.

There are valuable members who don't come here as much any more because of stuff like this.
Speaking of which, has anybody heard from MR. Horsepower recently?

Hand ported another LT4 intake going about as thin as I dared and it dynoed less across the board as compared to the intake with extra welding that did 480 rwhp. So welding and raising the port of the stock ones does help. Wasn't always sure of that.
Great info again Denny. It would be simply awesome if you could dig up dyno sheets to back that up for future reference. :D

Great info again Denny. It would be simply awesome if you could dig up dyno sheets to back that up for future reference. :D

Thats what this board needs along with all of the automotive calculators, a catalog of dyno sheets from various members. Maybe with a search function that could search based on different modifications, displacement, heads, etc. It would eliminate the need for those "How much HP will my car make..." threads.

Just an idea, Admins take note.

Jeremy

Great info again Denny. It would be simply awesome if you could dig up dyno sheets to back that up for future reference. :D

Some I have and some I don't. With about a 1000 dyno pulls ya can't save everyone, but I do have quite a few of them saved for reference. When you see me write 5 or 6 it means I don't remember the exact number but it's ballpark close enough. If it's important to me, I'll try and find the information.

Was more anal early on testing things and saving the dyno sheets. Now if I need something, just go to the shop where the dyno is and look at the computer. Even then I have a hard time finding which ones I want as there is probably 300 in that computer alone and my partner in crime has a shaky filing system in which he can only find some things.

I know what yo mean Denny. I have a folder of old timeslips. There are LOTS in the 14 and 15 second range still... I was digging through my car recently and found a couple more under seats, in the glove box, center console, map pockets, etc.

So for the LE2 cam, it seems to pull like mad up top, if I wanted it to pull in the 3000-5000 range I would need a 15" intake tract on top of the 6" intake tract on the head?

What is the length of the intake runner on the stock LT1 intake?

So for the LE2 cam, it seems to pull like mad up top, if I wanted it to pull in the 3000-5000 range I would need a 15" intake tract on top of the 6" intake tract on the head?

What is the length of the intake runner on the stock LT1 intake?


The stock intake has 3" runners.
Once ya get over 12" total runner length(head and intake) ya start loosing HP across the board above 3500. That is with a performance intake and engine. Smaller dia runners have to be longer or so it seems.

So no one really has a mathematical formula for the correct length and diamater of the intake tract?

What would I want the intake tracts on the intake to be? 220cc and 6" long?

So no one really has a mathematical formula for the correct length and diamater of the intake tract?

What would I want the intake tracts on the intake to be? 220cc and 6" long?

If you wanted to increase torque in the midrange then that would probably work fine. But I would suggest swapping cams too. If 3000-5000 is the range you want to be strong in then get a cam that is strong in that range.

Just my suggestion,

Jeremy

So no one really has a mathematical formula for the correct length and diamater of the intake tract?

What would I want the intake tracts on the intake to be? 220cc and 6" long?

Try this one:

The runner measured from the valve seat to the plenum (the open area where they normally meet under the carburetor,) can be determined by dividing 84,000 by the length of the runner = the speed the runner will work the best. An example is:

84000 (constant) = 5250 rpm
16 (runner length)

Try this one:

The runner measured from the valve seat to the plenum (the open area where they normally meet under the carburetor,) can be determined by dividing 84,000 by the length of the runner = the speed the runner will work the best. An example is:

84000 (constant) = 5250 rpm
16 (runner length)

16" minus the 6" tract in the head so a 10" runner in the intake? Correct? What diameter? Same as stock LT1 or can you go bigger to later accomodate 220 cc heads?

bigger, but not too big :D

Ok well thats what I need to know I guess. What diameter (cc) intake runners. :)

I'll dyno the car next month for a baseline and then take pics of the fabrication process and do a final dyno in spring.

16" minus the 6" tract in the head so a 10" runner in the intake? Correct? What diameter? Same as stock LT1 or can you go bigger to later accomodate 220 cc heads?


You DO NOT have a 6" runner in the head.
Ya need the CSA of the intake to figure the size.(H/W)

With that formula ya figure what RPM a given length works best at. Ya can't get the length to work best over a large RPM range but ya can give and take to make it spread over maybe 4000RPM's but closer to three would be about average.

16" minus the 6" tract in the head so a 10" runner in the intake? Correct? What diameter? Same as stock LT1 or can you go bigger to later accomodate 220 cc heads?

Be careful with that "84000" formula. It doesn't work for all valve durations.There is some good discussion on this on "Speedtalk" forum. Search for it.

Are you sure that the port centerline length in a LT1 head is 6 inches? I think it's closer to 5-3/8.

If you change the runner length you also need to change the cam. I believe the LE2 was designed for the stock LT1 runner length. My guess is that you won't be happy with a 16 inch total runner length.

Just my $.02.

Be careful with that "84000" formula. It doesn't work for all valve durations.There is some good discussion on this on "Speedtalk" forum. Search for it.

Are you sure that the port centerline length in a LT1 head is 6 inches? I think it's closer to 5-3/8.

If you change the runner length you also need to change the cam. I believe the LE2 was designed for the stock LT1 runner length. My guess is that you won't be happy with a 16 inch total runner length.

Just my $.02.


16" IS a bit long.
He needs more figuring to get there but he asked for a runner length formula.

Maybe I'm asking the wrong question.

With an LE2 cam and LE2 heads, is the stock LT1 intake perfect for it? Can you pick up more hp and torque in the midrange to get lower ETs with a better designed intake? If so, what would the new manifold look like, how long would the runners be, and what kind of improvement would I see?

Sorry for highjacking your thread grammerman.

Maybe I'm asking the wrong question.

With an LE2 cam and LE2 heads, is the stock LT1 intake perfect for it? Can you pick up more hp and torque in the midrange to get lower ETs with a better designed intake? If so, what would the new manifold look like, how long would the runners be, and what kind of improvement would I see?

Sorry for highjacking your thread grammerman.

The LE2 cam was designed to work well with the LE2 heads and the LT1 intake especially on a 350-355. Where you need more torque & power is probably dictated by your vehicle combination. As has been said many times before, getting the most torque in the rpm range you plan to operate the engine results in the best acceleration (assuming you can get it to the ground :) ) There are folks who don't need much below say 4000-4500 rpm because thay aren't drag racing, or they are using that much stall. That requires different valve timing, and perhaps intake runner lengths from a 2500-6500 rpm engine.

Look for information on the Super Victor single plane manifold LT1 conversions. A number have been done so some cam timing has already been worked out for 355, 383, and 396 displacements. I suspect it's different for each engine size.

Obviously displacement, head flow and vehicle matching will help determine a lot of the parameters. I think this has been addressed extensively in this forum.

FWIW, if I were considering building a manifold from scratch, I'd do a ton of simulation on a sophisticated sim program and I'd look closely at a program called "Pipemax" before I decided on length, CSA and taper as well as plenum volume. Doing all this well is a large task. An excellent knowledge of engine design would also be very helpful.

FWIW, if I were considering building a manifold from scratch, I'd do a ton of simulation on a sophisticated sim program and I'd look closely at a program called "Pipemax" before I decided on length, CSA and taper as well as plenum volume. Doing all this well is a large task. An excellent knowledge of engine design would also be very helpful.

Which is probably why Wilson and Hogan charge so much for theirs. :(

The reason I'm so interested in doing this is because my welder is willing to do the intake very cheap because he's a friend of mine. My engine builder told me that the intake was the bottleneck in my buildup as well. So I'm wondering if there is anything out there that would not require a huge leap in research to build. Maybe improve on the LT4 design a bit but not so radical that you have to start from scratch.

Is it possible to grind a cam so it will make power to 6500 rpms with a 6" long intake manifold runner? I ran a hotcam before my current le2.2. I have a stealthram intake that I welded up and redrilled for lt1 use, Like Brett's exept it had stock length 6" runners. With the stock intake the car pulled to 6400rpms. When I put on the stealthram the car made more torque but power peaked at 5900-6000 rpms. I havent tried this intake with my le2, as I have been chasing lots of bugs. I now seem to have it running right. Will this cam pull any where near 6500 with the longer runners?
Thanks for the info, this is a great thread.
Kory

Is it possible to grind a cam so it will make power to 6500 rpms with a 6" long intake manifold runner? I ran a hotcam before my current le2.2. I have a stealthram intake that I welded up and redrilled for lt1 use, Like Brett's exept it had stock length 6" runners. With the stock intake the car pulled to 6400rpms. When I put on the stealthram the car made more torque but power peaked at 5900-6000 rpms. I havent tried this intake with my le2, as I have been chasing lots of bugs. I now seem to have it running right. Will this cam pull any where near 6500 with the longer runners?
Thanks for the info, this is a great thread.
Kory


Ran a Stealth Ram on a 383 that would pull to 75/7800 with no problem. If ya got the head flow and the cam, it will go as high as ya want-- within reason. It had stock head castings flowing 300+CFM.

Bret can answer the cam question as I don't know the spects.

I just spoke with the guy that did Denny's manifold. He said I should look into modding the stocker. He said I would pick up some power and torque in the midrange with a sheet metal but I could pick up the same amount by reworking the stock LT1 intake by cutting it in half and welding, porting, etc. and it would be cheaper.

I could pick up the same amount by reworking the stock LT1 intake by cutting it in half and welding, porting, etc. and it would be cheaper.

Cutting in half ware ?? Just above the runners??
There was someone on here that was doing that, they cut down the back of the TB mounting surface and across the top of the runners.
Now if you were to build your own and incresse your runners by an inch and give your self a nice plentum you would be golden IMO.

The other problem that you will have is thet cast alum. don't weld very good at all.

I also think I have an idea on how to do a LSx type manifold but for a LTx motor but I have to work that one out yet???
Lets just say there is going to be a lot of welding and machining involved :o

Cast aluminum welds fine if it's clean, and you have good rods. I've done alot of welding on my stealthram.
Kory

BTW does any one know what the runner size (dia) is on the LSx motors?

1 7/8 ??

Moderators, if inappropriate please delete. But since there is so much talk about longer intake runners and there benefit, I'd like to mention the one-off BRE ProRam has been listed in the for sale section today. :eek:

I just spoke with the guy that did Denny's manifold. He said I should look into modding the stocker. He said I would pick up some power and torque in the midrange with a sheet metal but I could pick up the same amount by reworking the stock LT1 intake by cutting it in half and welding, porting, etc. and it would be cheaper.

Humm......Interesting! Asked Jeb before I bought the intake if he had any dyno data and he said no, so to my knowledge he is basing this upon me e-mailing him my before/after dyno sheets. And yes, it did pick up bottom and midrange with the existing cam and he does seem to be quite knowledgeable.

Still think the right cam will pick the top end up. Again, we'll see but I sure see a lot of longer intake runners on cars running a whole lot more rpm so something is going on that makes them pretty fast.

Craig @ GTP was doing the stock intake cut and weld stuff 8 years ago and a friend bought one. He had problems making power when I saw the car but claimed to have gotten it into the 480's in a 383 with AFR 227 heads and a big solid roller cam. Haven't seen any dyno sheets to substantiate his results and we all know how that stuff goes.

I dont see a stock manifold maxed out making more AVERAGE power than that sheetmetal or ANY longer(than stock) runner manifold..aint happening.


Pops and I had a buddy here in town, a 383, Holley stealthram(was not cutdown), Pops grind solid roller cam, monoblade throttlebody, 42 lb injectors,stock casting LT1 heads, 1 7/8 headers, 3 inch dual exhaust and a FAST system. At 3350lbs it ran 10.40's on motor, was never tuned to get the best out of it, easily had a low, low 10 second slip in it.....but he changed direction with the car.......I think his stealthram made that engine....but hey thats just me.


David

longer intake runners and there benefit, I'd like to mention the one-off BRE ProRam has been listed in the for sale section today. :eek:

Nice :) Did you evere get to run it?
What did you make for power?
How much longer are the runners on that than stock?

Well I just started looking through my GMHP Sept 2006 catalog and saw that Edelbrock makes a Performer RPM LT-1/LT-4 TB Intake for our cars #7107 LT-1 & #7109 LT-4 but I can't find it on thier site??

Well I just started looking through my GMHP Sept 2006 catalog and saw that Edelbrock makes a Performer RPM LT-1/LT-4 TB Intake for our cars #7107 LT-1 & #7109 LT-4 but I can't find it on thier site??

Here is a quote from another board, someone emailed Edelbrock about those intakes in February:


"this is the e-mail responce i got
Michael,

At this time we do not have a lot of details available regarding that product. This is disappointing since you and many other customers have been beating down our doors since it was announced. It is still in development but we expect it to be available for sale in a month or two. I do not have a projected MSRP or any technical specs available to me. Having thoroughly failed to answer any of your questions, I would like to thank you for your interest in Edelbrock products. Let me know if you have any other questions that I will be unable to answer.



Sincerely,

Aaron Jones

ajones@edelbrock.com

:confused: Well that is just crappy :(

I only know of one LT1 with a different intake, it was made by Hogan. Its on a 391 with AFR heads. On the motor, pump gas, race weight with driver at around 4200lbs it traps 122mph. Thats around 600hp to the rear wheels based on weight and trap speed. I'm thinking that the intake becomes a restriction at some point, but where? With all the LE and AI stuff running around putting down 400hp+ to the rear wheels it looks to be in that area.

BTW Check here for intake pic again: http://memimage.cardomain.com/member_images/3/web/747000-747999/747807_20_full.jpg

I only know of one LT1 with a different intake, it was made by Hogan. Its on a 391 with AFR heads. On the motor, pump gas, race weight with driver at around 4200lbs it traps 122mph. Thats around 600hp to the rear wheels based on weight and trap speed. I'm thinking that the intake becomes a restriction at some point, but where? With all the LE and AI stuff running around putting down 400hp+ to the rear wheels it looks to be in that area.

BTW Check here for intake pic again: http://memimage.cardomain.net/member_images/3/web/747000-747999/747807_20_full.jpg

Made 483 rwhp with a stock (ported and welded) intake with hydraulic cam.

Need to make it .com and not .net :)

4200lbs it traps 122mph. Thats around 600hp to the rear wheels based on weight and trap speed.

That's more like 600 hp at the flywheel, not the rear wheels. Probably <500 rwhp.

Mike

All the calculator I've pluged MPH and weight into give me around 600 at the rear wheels and anywhere from 700-750 at the crank. Remeber its a b-body at 4200lb!

122 mph at 4200 lb is not 750 fwhp.

I ran 133 mph at 3750 lb. Do the same math and you get 680 hp. The car made 550 rwhp in this trim, nowhere near the 680 hp that's calculated.

Right now, I run 143 mph at the same 3750 lb. The same equations yield 850 hp. Once again, I'm nowhere near 850 rwhp. The car now makes 680 rwhp.

Denny did you retain the MAP sensor on that Fabed Intake and did they keep it in the stock location?

Denny did you retain the MAP sensor on that Fabed Intake and did they keep it in the stock location?

Hooked up to a vacuum port via a hose on the back of the intake. Didn't realize at first all you needed to do was connect it to a hose
and was pretty stressed trying to figure it out until my partner just pluged it into a hose.

So simple it's pathetic.

Thanks Denny :)
Been on vacation since last friday :D

I know this is likie advanced notice but I have the Popular Hot Rodding for October and it has a very large article on Head flow and Intake flow.

Very long and indepth.