I'm building a "monster" what I keep calling my 2004 C5 that I have decided to build some nice power. It looks like I will be going the twin turbo route now, and also understand turbo applications not the best for endurance road racing, but I plan to still get out there and have some fun at the track when this is all put together. So my question is whats a good gear recommendation for a twin turbo built motor, i have no idea of what power we will be getting only that I plan to go big. I would want good gears for track and drag strip fun while still being about to get out on the weekends and fishing for trouble in the canyons? Any help would be greatly appreciated.

You know Tom is going to chime in!!!LOL I guess with all the preaching he does (and well deserving) some people just want to go the other direction!! JK I suppose RR every now and then won't be too bad with a TT set up! As far as gears go I think that the best for RR is 3.42. I am sure others will have other ideas, this is just my thought!! Good luck with the build though!

Greg.

Road Racing gears depend on the longest straight you are going to be using, and the most common gears are either a 3:73 or 3:90 but with a big rear HP twin turbo it will depend more on how much traction you are going to get. The bigger the gear the easier it will be for the motor to turn the wheels loose. I would stick with your stock 3:42 gear until you get out there and see what it does first or you might end up going backwards.
:cheers:

Down here in Nor Cal, most of the Road courses with moderately modded motors 500hp or less, we have been happy with 3.73s, but big HP & TQ would probably work best with 3.42s.

Just make sure that you upshift at redline. Some guys hold against the rev limiter if there is only a little bit of straightaway left, but C5 & C6 rev limiters pull fuel, not ignition, so holding against the RL with a hot engine at high rpm is a sure fire way to kill an engine. So either lift, or upshift.

Down here in Nor Cal, most of the Road courses with moderately modded motors 500hp or less, we have been happy with 3.73s, but big HP & TQ would probably work best with 3.42s.

Just make sure that you upshift at redline. Some guys hold against the rev limiter if there is only a little bit of straightaway left, but C5 & C6 rev limiters pull fuel, not ignition, so holding against the RL with a hot engine at high rpm is a sure fire way to kill an engine. So either lift, or upshift.
Good to know info on the rev limiter!:)

I have been running 3.73s with 460 rwhp on an ECS H/C 346. This winter we are putting in a LS7 ( :) love the sound of 427) in my car and I plan on keeping the 3.73s. I will be at VIR in the Spring and that will be the test. If they are too much then back down to the 3.43s.

For you I would stay with 3.43s and see how the Turbos spool up. If you find that you have lag then try the 3.73s and see if that helps make up the difference.

BTW - TT on the Road Course is a Killer. Way too much Heat to deal with. S/C would most likely be more predicatble as far as power and run somewhat cooler, but all of our Raod Race cars are H/C and/or big cubes.

:cheers:

Just make sure that you upshift at redline. Some guys hold against the rev limiter if there is only a little bit of straightaway left, but C5 & C6 rev limiters pull fuel, not ignition, so holding against the RL with a hot engine at high rpm is a sure fire way to kill an engine. So either lift, or upshift.

I always suggest adding Octane booster at the track or mixing in some race gas. You just never know when a bad tank of gas is going to bite you.

A shift light is also a good idea. You then can tell how much room you have before you hit the limiter and then decide if you want to shift or just hold it.