Camshaft gurus in here please!!
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Joined: Jan 2001
Posts: 108
From: Fremont, CA
Originally posted by mongse_1
The 4-bolt is better than the 2-bolt only if it's left alone. A splayed 4-bolt conversion on the 2-bolt block is better than the Vette block.
The 4-bolt is better than the 2-bolt only if it's left alone. A splayed 4-bolt conversion on the 2-bolt block is better than the Vette block.
Brian
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Joined: May 1999
Posts: 274
From: Rich, Va.
Ok gurus, here goes. This is a very good thread on camshafts. I see some say more lift, some say more duration. Well lets talk NHRA Stock Eliminator for a moment. LT1 stock eliminator cars, run stock displacement, stock heads, stock LIFT camshaft, any duration. Yes I know these cars are taken to the extreme of the NHRA rules, but you can't argure with fact, these cars perform. I have seen specs for one camshaft that I know was run in one of these cars, stock lift, lots of duration, in the 240 to 260 range, and a 106 centerline. I know this doesn't give the vital info out of the cam, but that's all I could get at the time. This car made 420 rwhp on the dyno, and yes it ran well. Now I know this is a Drag purpose car, but in all reality, you could drive this car on the street, might not be the best daily driver, but it could be done. What I would like to know, explain this to me, when one says more duration, but the other says more lift, this is just one example where alot of duration is working. Why?
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Joined: Oct 2000
Posts: 786
From: Charlotte, NC
Well, I was with J***** race trans. for 3 years.. and was lucky enough to be around alot of stock eliminator stuff 
I know what youre talking about.. which is why i said duration is what makes a cam 'big.' Never the less... One example.. a buddies stocker 283... heads arent cheated up or anything.. 24X/24X cam on a 106 with .398 lift with a stock stamped 1.5 and it made 312fwhp I believe.. probably a few more later with some tweaks, but nothing special. Never the less... its not lift, or duration by themselves tha tmake power. It's area under the curve... you can get it with alot of lift, or insane ramps.. but at some point you have to make a compromise b/c you can only open/close a valve so fast without greatly increasing somethings propensity to eat itself alive.
It's a function of lift and duration.. thats all there is to it... open/close it as fast as you reliably can... and then work on duration/lsa methinks.
I know what youre talking about.. which is why i said duration is what makes a cam 'big.' Never the less... One example.. a buddies stocker 283... heads arent cheated up or anything.. 24X/24X cam on a 106 with .398 lift with a stock stamped 1.5 and it made 312fwhp I believe.. probably a few more later with some tweaks, but nothing special. Never the less... its not lift, or duration by themselves tha tmake power. It's area under the curve... you can get it with alot of lift, or insane ramps.. but at some point you have to make a compromise b/c you can only open/close a valve so fast without greatly increasing somethings propensity to eat itself alive.
It's a function of lift and duration.. thats all there is to it... open/close it as fast as you reliably can... and then work on duration/lsa methinks.
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Joined: Oct 2002
Posts: 6,518
Originally posted by FRDEATR
What size cam are you running in these? Sounds like something I want
I plan on getting the absolute best forged internals. Also, I thought that the LT4 heads are better than the LT1's (higher runners). Nostang 96z had his ported by GTP and these were his numbers:
Lift Intake Exhaust
.200 152.4 117.1
.300 216.6 157.7
.400 253.1 198.3
.450 269.8 213.7
.500 285.0 222.7
.550 295.9 226.9
.600 301.5 229.4
.650 302.7 n/a
301/229 @.600 is pretty respectable. Plus I'm getting the heads for free, so... Also, don't you think that a 4-bolt main (LT4) would be better than the 2-bolt main (LT1)?
In this case, money is no object. Well, it is, but I'm willing to spend what I have to to make a bulletproof motor that will last. That's why I don't want to have to tach it too high. Midas well do it right the first time, heh? Let me know what you think Later,
Brian
What size cam are you running in these? Sounds like something I want
I plan on getting the absolute best forged internals. Also, I thought that the LT4 heads are better than the LT1's (higher runners). Nostang 96z had his ported by GTP and these were his numbers:
Lift Intake Exhaust
.200 152.4 117.1
.300 216.6 157.7
.400 253.1 198.3
.450 269.8 213.7
.500 285.0 222.7
.550 295.9 226.9
.600 301.5 229.4
.650 302.7 n/a
301/229 @.600 is pretty respectable. Plus I'm getting the heads for free, so... Also, don't you think that a 4-bolt main (LT4) would be better than the 2-bolt main (LT1)?
In this case, money is no object. Well, it is, but I'm willing to spend what I have to to make a bulletproof motor that will last. That's why I don't want to have to tach it too high. Midas well do it right the first time, heh? Let me know what you think
Later,Brian
I have mentioned a cam that I was interested in already. I will not give specifics but I only use that much duration on 400 and up small blocks. (400, 427) The thing is it only really works with the heads that i'm usuing. We're talking about 23 deg heads that are 215-230cc's and flow like crazy. Basically the cam I mentioned about the 383 is a good cam, my 350-383 combos use a much smaller cam.
As for the heads how much are they total? For $2450 for AFR you can be sure that you are getting those numbers at least CNC ported so they are all the same. http://www.airflowresearch.com/pages/images/charts/195cc-LT4-Comp-Head-Flow2.gif I cannot stress enough how important CNC heads are. Those AFR 195's are very good for the price and a streetable head. (If had the perfect combo say with a 383 I would go with the 215 CNC ported AFR Raised Runners. But then you looking at $4000) Then again the heads are free.
On the GTP front. I have a friend who says the exact same thing about them and their numbers. They have some good performing LS1 heads, but their numbers are really not that impressive.
As for the block. Get some steel 4 bolt splayed mains and have them installed on your block. Yes you need to line hone it but then you'll know it's right.
I would echo what everyone else has said. BUY GOOD HEADS! Then get a cam to match it. When you have good flow numbers then you can have less cam and make more power.
o.k. now onto the TQ front. Yes I design engines that are all mid to high end TQ, that's how you make HP and win races. I gotta scan the dyno sheet from my 365 cube small block, or just get a sample of it off the computer since that thing is right within 1%. I'm in the camp where as a race driver if there is not enough torque to spin the tires from one corner to the next it's not enough. (BTW anyone know who said that first?) My right foot is there to control it and so I want as much as I can have. Anyways with SBC it's hard to get too much, now with a Big Block it's a different story.
The stock elminator cars are interesting. Since they stick to stock lift then duration is the only way to get area under the curve. Or use controled valve toss. That's expensive and risky but it works.
Yes this is a great thread. To bad it doens't sell my motors.
lol
Bret
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Joined: Oct 2000
Posts: 786
From: Charlotte, NC
We've had several sets of "competition cnc ported" AFR's.. and eh.. its NOT worth the price premium IMO. We've never had an AFR head flow what they claimed it'd do either. Theyve gotten closer in the past year, but eh.. still wasnt what they claimed.
Never the less... if you go with an aftermarket casting, i'd buy it bare, and then have someone who knows what theyre doing work it. You'll spend maybe $100 more depending on who yo ugo with, make alot more power, and youll get name-brand components as opposed to the stuff they throw in them. Good hand stuff is consistent, our stuff is usually within 1% port to port. CNC is cool, but eh.. they only do it to make $, and theyre making truckloads of it off their "competition port" methinks.
Not to say that there's anything wrong with it of course, its a good head, but you could get alot more hp/$wise elsewhere.
*shrug* yer $ though, and as much as we'd like to.. i suppose we cant all take turns spending it
Never the less... if you go with an aftermarket casting, i'd buy it bare, and then have someone who knows what theyre doing work it. You'll spend maybe $100 more depending on who yo ugo with, make alot more power, and youll get name-brand components as opposed to the stuff they throw in them. Good hand stuff is consistent, our stuff is usually within 1% port to port. CNC is cool, but eh.. they only do it to make $, and theyre making truckloads of it off their "competition port" methinks.
Not to say that there's anything wrong with it of course, its a good head, but you could get alot more hp/$wise elsewhere.
*shrug* yer $ though, and as much as we'd like to.. i suppose we cant all take turns spending it
Registered User
Joined: Feb 2001
Posts: 1,450
From: Belleville, IL
Bret's right...get the four-bolt splayed caps and remember to line hone the cylinders. I know Oliver makes them and I'm sure there's more but it's 6:30am, and the brain's only working on one hamster right now.
The splayed caps are better than the standard 4-bolt b/c the splays are put at an angle(more strength), whereas the standard block have vertical studs.
The splayed caps are better than the standard 4-bolt b/c the splays are put at an angle(more strength), whereas the standard block have vertical studs.
Registered User
Joined: Aug 2000
Posts: 556
From: Chicago, IL
Well, its not just that they are better because they are at an angle....the reason is because of where the bolt goes into too.
there is much more material in the webbing of the block than striaght down like a conventional 4 bolt main....
there is much more material in the webbing of the block than striaght down like a conventional 4 bolt main....
West South Central Moderator
Joined: Oct 2000
Posts: 3,371
From: Kilgore TX 75662
Originally posted by SkarodoM
As far as what mindgame mentioned.. thats a good point. People are dumb.. they want "torque torque torque"... well theyre not really asking for torque, theyre asking for lowend torque, as opposed to highend torque. Yeah.. you want alot of area under the curve, but unless you want to tow with your car, HP is what you want.. mid-highrpm torque. Make hp, gear to take advantage of it, and spank the **** out of everyone else who smokes the tires & runs out of breath up top when it's finally hooking up
As far as what mindgame mentioned.. thats a good point. People are dumb.. they want "torque torque torque"... well theyre not really asking for torque, theyre asking for lowend torque, as opposed to highend torque. Yeah.. you want alot of area under the curve, but unless you want to tow with your car, HP is what you want.. mid-highrpm torque. Make hp, gear to take advantage of it, and spank the **** out of everyone else who smokes the tires & runs out of breath up top when it's finally hooking up
Originally posted by SStrokerAce
o.k. now onto the TQ front. Yes I design engines that are all mid to high end TQ, that's how you make HP and win races. I gotta scan the dyno sheet from my 365 cube small block, or just get a sample of it off the computer since that thing is right within 1%. I'm in the camp where as a race driver if there is not enough torque to spin the tires from one corner to the next it's not enough. (BTW anyone know who said that first?) My right foot is there to control it and so I want as much as I can have. Anyways with SBC it's hard to get too much, now with a Big Block it's a different story.
o.k. now onto the TQ front. Yes I design engines that are all mid to high end TQ, that's how you make HP and win races. I gotta scan the dyno sheet from my 365 cube small block, or just get a sample of it off the computer since that thing is right within 1%. I'm in the camp where as a race driver if there is not enough torque to spin the tires from one corner to the next it's not enough. (BTW anyone know who said that first?) My right foot is there to control it and so I want as much as I can have. Anyways with SBC it's hard to get too much, now with a Big Block it's a different story.
I'll be doing a cam swap during this winter (with stock heads w/pressed in studs), then ported aluminum heads later down the line (probably 6 months), and then a bigger lift cam to match the heads. The stock specs for my current cam are 191/196@.050, .418/.430" with 1.5 rockers on a 111LSA, a hell of a bottom end torque monster. But, I put in a 3200+stall Vigilante (I'm always above 4000RPM at WOT) and 3.73s to get it ready for a bigger cam later. I'm having all kinds of traction problems, even on ET Streets. I WANT to give up bottom end to help me hook. I know, I could just feather the throttle, but where's the fun in that? I want to floor it and go! I also want to be able to hang with the bolt on LS1 F-body guys on the highway.
So, I'm thinking I should go with a bigger cam than I really need, I'll make up some torque later with the new heads (I'm wanting a little over 12:1CR) and that will also help with the top end.
Also, if I want to launch harder, I'll just hit the button sooner
Yes, I'll be spraying it as well. I hear people say that you should go with a wider LSA for engines that will get sprayed, but I don't want it to be just a nitrous motor. The bottle will be closed a lot more than it will be open. I just want to use it for an extra kick in the pants when the 5.0 beside me thinks he's got it won by a carlength on the impy Here is an early example of what my head porter has gotten from a set of aluminum LT1 heads.
.lift I / E %
.100 83/ 70 84
.200 149/122 83
.300 205/158 77
.400 242/189 78
.500 280/205 73
.550 283/210 74
[ul].600 286/214 75[/ul]
E / I 78
It will be using the stock bottom end (LT1 350) for another few years. I want to shift at about 6700RPM after I do the heads.
Originally posted by SStrokerAce
Intake closing point is the "MOST" important spec on a cam, now you can advance the **** out of a cam, you can spread the lobes apart to run alot of duration to get the intake valve to close at the right time. Or you can do it the right way, get a better lobe, run less duration and more lift and put it in the right spot.
Believe me, a cam is right when you are running it strait up and it makes power. Advanced or Retarded is a crutch IMHO and you will always get more average power if you have a cam that runs the best strait up.
Intake closing point is the "MOST" important spec on a cam, now you can advance the **** out of a cam, you can spread the lobes apart to run alot of duration to get the intake valve to close at the right time. Or you can do it the right way, get a better lobe, run less duration and more lift and put it in the right spot.
Believe me, a cam is right when you are running it strait up and it makes power. Advanced or Retarded is a crutch IMHO and you will always get more average power if you have a cam that runs the best strait up.
What cam would you guys recommend for me? I was thinking Comp lobes 3313 & 3315 to go with the stock heads w/1.5 roller rockers and on a 110LSA.
Last edited by AdioSS; Oct 16, 2002 at 02:02 PM.
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Joined: Jan 2000
Posts: 173
From: from the land of Justin Wilson and Huey Long!
Originally posted by SStrokerAce
Intake closing point is the "MOST" important spec on a cam, now you can advance the **** out of a cam, you can spread the lobes apart to run alot of duration to get the intake valve to close at the right time. Or you can do it the right way, get a better lobe, run less duration and more lift and put it in the right spot.
Believe me, a cam is right when you are running it strait up and it makes power. Advanced or Retarded is a crutch IMHO and you will always get more average power if you have a cam that runs the best strait up.
Today we have so many good clyinder heads, it's a shame to see the same old tricks of throwing too mcuh duration at them.
Intake closing point is the "MOST" important spec on a cam, now you can advance the **** out of a cam, you can spread the lobes apart to run alot of duration to get the intake valve to close at the right time. Or you can do it the right way, get a better lobe, run less duration and more lift and put it in the right spot.
Believe me, a cam is right when you are running it strait up and it makes power. Advanced or Retarded is a crutch IMHO and you will always get more average power if you have a cam that runs the best strait up.
Today we have so many good clyinder heads, it's a shame to see the same old tricks of throwing too mcuh duration at them.
Go look at the LS1 engines. 346 cubes, 224/224 with 300+cfm heads flat out spanks a awesomely preped LT1. Why? The heads, the Lift that the 1.7's give you.
I just get sick of seeing undriveable cams recomended to most guys when what they really feel and get gains from is more torque.
BTW have you ever seen Lingenfelters cams? Always low duration and lots of lift. That's why everyone loves drivng his cars. Hmmmm a 219/219 .560/.560 @ 112 that sounds like a good cam to me.
You guys have some awesome heads out there now, so it's not an excuse.
Done with rant......
Bret
I just get sick of seeing undriveable cams recomended to most guys when what they really feel and get gains from is more torque.
BTW have you ever seen Lingenfelters cams? Always low duration and lots of lift. That's why everyone loves drivng his cars. Hmmmm a 219/219 .560/.560 @ 112 that sounds like a good cam to me.
You guys have some awesome heads out there now, so it's not an excuse.
Done with rant......
Bret
(BTW, he uses N2O which seems to work perfect with his combo)...
I think I would understand (as would others viewing this thread) what dynamics are present in figuring why his combo seems to work so well, at least for him...
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Joined: Oct 2002
Posts: 6,518
O.k.
First. The right cam for a setup is IMHO strait up. It is always a good idea to degree in a cam. If you have the dyno time try all the combos. I have found the right cam is when you put it in and you don't need any advance or retard to make it right. If you think about it. If the cam is too big, and the LSA is too wide to compensate for it then you need to advance the cam to get the intake valve closing point in the right spot. Just what I have found in the last 16 years.
I'm sure your friend has a fast ride. Slightly ported LT1 heads are not that high flowing, since the Vortec L31, LT4 and Impalla SS heads should out flow that set stock. A 232/232 should work for him fine, in fact it's not a bad choice, just not mine. That cam will give him good lobe area, with that much duration he is just losing TQ below TQ peak, that's all. I would guess that with .560 lift he's using 1.6:1 rockers. That's a perfectly good setup. With N2O I might want more exhaust duration.
Now the part you quoted from me..............
219/219 .560/.560, the only difference here is the fact that the duration is lower. With better heads this cam would make as much or more HP and WAY MORE TQ. It has a better idle and has more driveability.
Why did you pick my post to cut up, what did I do to offend you? I express what I feel are good choices. You know why, because the guys who are giveing the advice 90% of the time are racers and their cars go fast so the guys that want a faster street car listen to them. 75% of the guys who want to have a faster street car are not going to make all out racers, hell my SS is a daily driver, I want 550hp but I also want to get in and enjoy it in all traffic situations. The 25% should not be telling the 75% that they need a drag racing cam, that's all i'm trying to say. There is a happy medium and I just try to help those guys out.
Bret
First. The right cam for a setup is IMHO strait up. It is always a good idea to degree in a cam. If you have the dyno time try all the combos. I have found the right cam is when you put it in and you don't need any advance or retard to make it right. If you think about it. If the cam is too big, and the LSA is too wide to compensate for it then you need to advance the cam to get the intake valve closing point in the right spot. Just what I have found in the last 16 years.
I'm sure your friend has a fast ride. Slightly ported LT1 heads are not that high flowing, since the Vortec L31, LT4 and Impalla SS heads should out flow that set stock. A 232/232 should work for him fine, in fact it's not a bad choice, just not mine. That cam will give him good lobe area, with that much duration he is just losing TQ below TQ peak, that's all. I would guess that with .560 lift he's using 1.6:1 rockers. That's a perfectly good setup. With N2O I might want more exhaust duration.
Now the part you quoted from me..............
219/219 .560/.560, the only difference here is the fact that the duration is lower. With better heads this cam would make as much or more HP and WAY MORE TQ. It has a better idle and has more driveability.
Why did you pick my post to cut up, what did I do to offend you? I express what I feel are good choices. You know why, because the guys who are giveing the advice 90% of the time are racers and their cars go fast so the guys that want a faster street car listen to them. 75% of the guys who want to have a faster street car are not going to make all out racers, hell my SS is a daily driver, I want 550hp but I also want to get in and enjoy it in all traffic situations. The 25% should not be telling the 75% that they need a drag racing cam, that's all i'm trying to say. There is a happy medium and I just try to help those guys out.
Bret
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Joined: Mar 2001
Posts: 130
From: Bliss
There is something being completly missed in this thread. You can have the best head and a perfectly matched cam and screw it all up with the wrong intake.
There was reference to LT4 intakes in a previous post as being a superior intake. GM put alot of time and $ into the design of the LT4 head, it is a superior design. It turned out though that they put too much time into the design and had to put together the intake almost last minute. As a result it does not let the heads work as well as a flow bench says they should. The flow #s you see with almost any port job is just of the head and not of the head and intake. Flowed together a properly ported LT1 setup will equal that of a ported LT4.
There was also a reference to the Accel Super Ram. I have seen the super ram in operation (small block version) and was impressed with it when it was on 305 inches of motor; however, it does not seem to run very well with RPMs or bigger inches (by very well I mean it produced 425-450 hp range with several cams and 450 ft-lbs in a L98 391 stroker as compared to 525 hp with a TPIS mini ram that is similar to a LT1 intake).
When thinking through heads and cam you must think of the intake as an extension of the intake port. Nobody would just post an exhaust port and call the heads ported. By the same token just porting the intake without reshaping the intake (not just a gasket match but a real shape change) dosen't get the job done.
BBB
There was reference to LT4 intakes in a previous post as being a superior intake. GM put alot of time and $ into the design of the LT4 head, it is a superior design. It turned out though that they put too much time into the design and had to put together the intake almost last minute. As a result it does not let the heads work as well as a flow bench says they should. The flow #s you see with almost any port job is just of the head and not of the head and intake. Flowed together a properly ported LT1 setup will equal that of a ported LT4.
There was also a reference to the Accel Super Ram. I have seen the super ram in operation (small block version) and was impressed with it when it was on 305 inches of motor; however, it does not seem to run very well with RPMs or bigger inches (by very well I mean it produced 425-450 hp range with several cams and 450 ft-lbs in a L98 391 stroker as compared to 525 hp with a TPIS mini ram that is similar to a LT1 intake).
When thinking through heads and cam you must think of the intake as an extension of the intake port. Nobody would just post an exhaust port and call the heads ported. By the same token just porting the intake without reshaping the intake (not just a gasket match but a real shape change) dosen't get the job done.
BBB
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Joined: Oct 2002
Posts: 6,518
Tell me about it. The LS1 intake is a good design it just hurts power a ton.
First, you don't need 100% of the flow the heads are giving you on street cars. It's in the tuning where a intake wins. The lat 10% of the intake flow is usually not worth the size of runner you have go to, to get that flow.
Focusing on Heads and Cams is where the power is, going to the intake is the final stages of tuning and power.
Bret
First, you don't need 100% of the flow the heads are giving you on street cars. It's in the tuning where a intake wins. The lat 10% of the intake flow is usually not worth the size of runner you have go to, to get that flow.
Focusing on Heads and Cams is where the power is, going to the intake is the final stages of tuning and power.
Bret
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Joined: Oct 2002
Posts: 6,518
Originally posted by twells
So you guys are saying good heads and a smaller cam (lt4 hot cam) will give good hp numbers as well??
i am kinda confused???
So you guys are saying good heads and a smaller cam (lt4 hot cam) will give good hp numbers as well??
i am kinda confused???
Bret