[Vettezuki]

Long saga, but finally thanks to ThrottleCrazy and 94cobra69ss296 got to measure the back pressure on my Vette. It has some "resistance to flow". It's about 1 psi on idle and 3psi at full throttle. The cats are the main issue, but unfortunately with recent CA law those have to be EO numbered. I could put on a set of LT headers and hi-flow cats and keep the stock stuff for "contingencies" and probably pick up a fair bit of power. I'm at 391WHP now. The motor with headers and hi flow cats (but an LS1 and not LS6 intake) and a few other differences, made about 430 WHP. It's a guess, but I'm think LT headers, hi flow cats, (maybe a new set of injectors as at least one of my is dodgy sometimes) should put conservatively at 410+ I would think

[enkeivette]

Will the LS6 intake not fit? You only have 2 1/4" pipes too right? Need to step it up to the 3" pipes and some long tubes.

[Vettezuki]

Originally Posted by enkeivette

Will the LS6 intake not fit? You only have 2 1/4" pipes too right? Need to step it up to the 3" pipes and some long tubes.

I have the LS6 intake. The Vette the motor was on had the LS1. I mean to say in this case I breate even better than it did. I have 3" pipes (I think, definitely bigger than 2 1/4") after the cats. I have stock manifolds and cats and that's where the bottleneck is.

[enkeivette]

After the cats? :toetap:

[Vettezuki]

Originally Posted by enkeivette

After the cats? :toetap:

The stock manifold are not pipes. I thought you were referring to after the cats. Are we gonna have another semantics smack down.

[BADDASSC6]

Good do all that then drop a big cam in it!

[94cobra69ss396]

If I remember correctly the tubing up near the cat was pretty small. I would guess that it was only 2.25. I would also recommend larger exhaust but I don't think you would need larger than 2.5. You would definately make more power with a free flowing exhaust system.

[BRIAN]

Hey Ben do you have a dyno chart you can share here? How did you measure "back Pressure?" I may want to try it on my exhaust.

[Vettezuki]

Originally Posted by BRIAN

Hey Ben do you have a dyno chart you can share here? How did you measure "back Pressure?" I may want to try it on my exhaust.

There is a pressure gauage that inserts into the O2 bung ahead of the cat.

Here's my last dyno sheet, with the setup as it is. 391/369.

[Vettezuki]

Originally Posted by BADDASSC6

Good do all that then drop a big cam in it!

Would love to, but then I wouldn't pass the sniffer anymore. I'm have a 114LSA 224/224. My emissions are still safe, but pushing the boundary.