1sickz51vette

Okay guys, my car has always been a factory freak as they call it for running a 12.7 @ 112 mph with just a twin flow intake and borla straight pipes untuned. My buddies friend has a 99 FRC with a modified stock airbox, stock catback, but LS6 intake manifold, and B&B shorty headers untuned. I have NEVER lost to a vette with like mods, both being 6 speeds. We are fortunate that he has property and a private runway to test our vehicles out in the middle of the state. we started in 2nd gear at 45 mph and instantly i jump out about 1/2 car, but as soon as i slam 3rd gear he is pulling on me by 3/4 a car to a car through third gear. I slam 4th gear and start reeling him in until rev limiter in 4th we are nearly side by side. I've never seen a stock ls1 pull that much harder then mine in 3rd gear, it was definately a noticable difference. Will the LS6 intake manifold and the shorty headers alone give him that much gain to where he is pulling me like that? I've raced other C5's with an Ls6 manifold and had NO problems walking them in every gear. My friend with a LS1 Z28 camaro that has headers, intake, tune etc says he beats the 99' FRC as well.... All this sounds funky to me as I have raced another z28 with same mods it was dead even side by side. Am i losing power somehow or why would he be pulling harder in 3rd gear then mine pulls back in 4th? I am very curious. Also my friend with the 02' z28 says his heads flow better then mine and they are not 243's off the Ls6. ANYONE?!?

Tar Heel

I cannot give you exact numbers or performance data but yes, the LS6 intake is an improvement over the LS1. I would guess though that the headers are making the difference. We put a set of long tubes on this summer and our tuner said they're typically good for 50rwhp depending on the other components to the exhaust and tune. I understand you're both untuned but the LS6 intake and shorties will make a noticeable difference.

Scott

danieloneil01

50rwhp?

1sickz51vette

I've heard of 40 rwhp gains on pre 01' Ls1's with an las6 swap and longtubes with a dyno tune the highest so far... This guy had an ls6 manifold, b&b shorty headers, stock catback, modified stock airbox, and supposedly no tune.

RedZMonte

Few things i would say make a difference.
* FRC is ~100lbs lighter
* LS6 intake/Shorty headers will give great midrange/high rpm gains over LS1 (assuming you have a pre 2001 LS1.. 2001+ LS1 has a LS6 style intake)
* Driver, good shift vs ok/bad shift would allow a good jump.

Jeffwilson34

I have a 98 A4 ls1 with a tune, long tube, straight pipes back tp quad borla, ls6 intake, vararam. and a shift kit in the transmission. It has the Z51 option so it has the 2.73 gears. I have ran 11.2 one time but more constant 11.6 to 11.8 I have a bad problem with spinning the tires at launch and going from 1st to 2nd with TC off with it on I am slower.
I have a problem with torque management that I have not been able to track down, I picked up power with it not working. I am told it can be adjusted or turned off in with a tune.
It has over 300,000 miles on it. I have been having some O2 sensor problems I got them fixed now my mass air flow sensor is acting up.
My last run over 12 but that was using scanpro and my laptop. But when comping it to the results at the Bristol, TN drag-strip street fight nights it is pretty accurate.

With all I have done to it, the long tube headers and straight pipes had the most noticeable difference in performance.