Is there a direct relation between the two, ie: the longer the intake runner the longer the exhaust primary needs to be? Or, am I way off on this one? I have often thought this to be true since the is almost no gain over shorties with lts on LTx motors, compared to vice versa on the LSx motors. Or does the basic design of the 2 motors, as in heads qand such, have a bigger impact on this?

Thanks
Jeremy

 

Your headed in the right direction. Runner size and length on both ends is important.

They are also independant of one another too, the intake manifold length is more important than the exhaust. Most times the proper exhaust length is easier to achive.

Cam timing can help alot of these issues.

This can get much more complicated and in depth, especially on evenly spaced intake ports like a SBF and a carb setup. Not going to get into that though.

Is it worth while on a street LT1? probably not, because you would have to build headers. (not a big deal if that's your thing) But you would get more by playing with different intake manifolds and porting/sizing them to what you need.

I would say that the heads on the LS1 are one reason why you see more. They are a much better casting stock for stock and the low stated power of the LS1 takes alot of choking off to get it there. The extra power output of the LS1 is just helped more by freeing up it's restriced exhaust system, if the LT1 made those kind of numbers then you would see more of a gain from shorties. Still the longer bigger tapper runner in the LS1/6/X intake is very helpfull to the TQ production of the motor.

Bret

 

Do the tube cross section need to be similar on the 2 also? I kind of figured that cam timing would come into play some how in this, just didnt know how. So, if you were to put headers on say a EFI 302 and a TPI 350 motor, would it be a good idea to go with long tubes with small tubes to match the size of the runners on the intake? Would it be safe to say that, in general rule, the larger the cam, the larger the cross section of the intake and exhaust primary needs to be?

I read a post you made and was reading how that when the intake and exhaust are matched properly, with the right cam, a motor could get away from an engine dyno bcuz it builds so much "faux boost", is what I think you called it. You also said that is the reason you use single plane intakes, with lots of work, and 1 7/8 headers. Whatkind of effects would a setup like that have on part throttle driving?

 

No that depends on HP level, cubes and RPM range.

Longer exhaust runners with a smaller pipe I.D. will make more TQ down low, so you basically help the are where the TPI and EFI work well.

Maybe. If you have alot of cam, which in turn can mean alot of RPM then the bigger I.D. of the exhaust pipes. But that might no be the best way to go.

Depends upon the cam and the cross section of the runners in proportion to the cubes you are running under the intake. It can have a very good or a very bad part throttle drivabilty.

The "*** boost" is when a intake has tuning pulses that increase the VE of the motor. Single planes seem to have a take of point were the tunning pressures (aka fax boost) increases very fast and you gain alot of power in a short amount of RPM so the motor gets away from a manually controlled break on a dyno.

Here is a article that gets into some of this stuff.

Keys to more power through intake manifolds and induction system components

Bret

 

I guess my real question is: Is it possible to create "*** boost" in a fuel injected motor with avalible intakes, or does it cost too much to create the "*** boost" with modifing intakes and headers?

 

The air doesn't care if it has fuel in it or not.

The LS1 makes so much more TQ than a LT1 due to the longer runners in the intake. Every intake will have a tuning pulse associated with it.

The 3" long LT1 runner doesn't do a very good job of it untill high in the RPM band. The 8" long tappered Ls1 runner does a better job at lower RPM, which makes it a much better intake.

You have a LT1 intake so you basically want a better alternative right?

Bret

 

this topic reeks of carb style intake conversion

 

Which one/s would you have in mind? What would be good for our cars. Victor, Victor Jr. Weind team G ????

 

Bret's working on a Super Vic conversion for a customer. Runners are about 5.5 inches long.

IMO, a Jr. has too short runners. Team G is a possibility.

 

I wish I had all of their articles online. I've got about 7 years of engine tech from them and will have a subscription until I die
There was a very good series on technology transfer from Nascar, I think this was part of it (Didn't even look at the link, i've prolly got it memorized )

Everyone should at least browse Circle Track Racing & Technology while they are in the check out line

-Shannon

 

And Muscle Mustangs and Drag racing mags, and other 5.0 Ford rags technical sections. Hide them if you buy them and drive a Camaro or Vette.

 

Bascially, yea. I would like a LS1, but college and LS1 dont go in the same sentence together. If I got a Mustang, , I would put a 351 in it, I hate 302s everyone has one. I also like the TPI motors now that the budget affortible stealth ram is out. I like the idea, and if you can get it to work on the street, you could really suprise some people.

 

Jeremy, it sounds to me like you need to build yourself a 3rd gen with a carburated SBC in it.
Compared to the LT1 the SBC has 100X more aftermarket parts, and it seems as though you want to do something no one else has done. You might also do a 3rd gen big block project. More money but again, more exclusivity and more fun.
Hey BTW where are you going to school these days?

 

Yeah a Super Vic is the only way to go single plane. There are some Wieand ones for Raise Runner EFI setups that are nice too.

I've been looking at a few more intakes to see if they are do able too, a customer just gave me a very good idea of one to look at too.

The short runners on the LT1 is a pain, there is some serious power to be had there with longer runners.

Bret

 

LOL.


Yes. They do have alot of good tech info, and interesting stuff. I have been reading them for years.

But honestly when I finish reading, I put them at the bottom of the pile, or don't keep them out in plain view too much like the Super Chevy, Chevy High Performance, etc... so that they can't be seen if somebody walks in. LOL (seriously)