rcallen484

Thanks to some folks over at the performance forum, I learned that the LS7 (and LS9 ) come with a factory short tube header setup. See image below. Has anyone put same on their LS3?

Boomer111

Sure, do a search this subject is brought up often.

I have done it along with the rest of the LS7 exhaust minus the over axle pipes and mufflers.

A 3 inch to 2 1/2 inch hook up must be made using stock LS3 axle over pipes.

rcallen484

Any idea what just this mod does in terms of hp or does it only make sense in combination with other mods?

HOXXOH

Some of the hundreds who have done that mod have reported 12-15 HP. Most don't really know or care about the numbers, but do recognize the power increase. I ran a best of 10.82 with that setup, which was quicker than many with headers. I now have headers and have run about .07 quicker than I previously did in comparable air.

2008LS3

I have full ls7 manifolds/cats/midsection with stock NON Npp 2008 Mufflers. The car is still silent at idle and really sounds beast now when WOT. I had alot of other mods done at the same time as the manifolds and also was street tuned. The car did feel noticably faster after everything is done.

Im going to be installing a cam with these manifolds and am anxious for results.

stoessjc

I put the entire exhaust system on my 08 z51. Manifold to mufflers. I did the mod on the z06 mufflers too. Like the sound. Not sure about power increases. I did this because it was cheaper then the NPP mufflers, which I did not have on my C6.

peter pan

I put a ZR1 complete exhaust on our 09 a few months back, felt it had a tad more grunt. Fast forward to February and I got a Chuck Cow tune and my only other mod is an Airaid CAI that was on before the exhaust. Do not have dyno numbers yet, but my 1/4 times went from 12.9 to 12.4 and I like the way my vette sounds and runs better now

boraxman

I will be doing this at some point, have manifolds and cats sitting pretty. I am surprised you can pick them up for so cheap.

I also bought a mid pipe that a fellow board member had custom made but still may go Borla or Corsa ZO6 instead.

rcallen484

The really attractive thing about this mod is that it should not effect the car's ability to pass state emissions. If longtubes reduce cat efficiency that might not be the case.

0Chuck CoW

Thank you....

If anyone LOCAL TO ME is interested in a similar mod, I should be able to help you out.

Call any time.

Chuck CoW

Boomer111

I think it makes sense with just a tune and the conversion, nothing else.

I picked up 40 rwhp. (Adjusted for 4:10 gearing by adding 10 hp.)

Tune makes good gains I saw 25 rwhp and 19 rwtq.

Picked up another 3-4 hp and lost 7 tq before adjusting for the addition of the 4:10's. I went with 10 hp/tq, not really sure how accurate this number is. So I saw a adjusted 413 and 403 with 400 both hp and tq with just a tune up from stock 375 hp 381 tq. I had 422 both hp/tq with AR 1 3/4 headers and Vararam. The Vararam was taken off and replaced with stock filter for dyno run with the Z06 conversion. Yes the headers give a big jump in tq that the Z06 conversion lacks. In my case with the 4:10's I do not miss it as much. If you can run headers and keep the car on the road with testing etc. this is the best deal, otherwise for those of us with strict testing the Z06 set up brings some adequate hp gains.

The other plus is a throatier sound with the larger 3 in. tubing.

The differential change brings the biggest seat of pants change. But it can run $2,500 installed and the Z06 set up installed with tune may set you back $1,200, depending.