I was just wondering what you think the optimal gear was for me. My car is a 94 Z28 6-speed (stock 3.42 gears) with mildly ported stock heads and comp 230/236 cam with LT's, etc... Figure I'm putting down in the area of 350 rwhp, and given my cam, I would think peak power comes pretty high in the RPM range, cutoff is at 6500 RPM. The car currently traps between 108-109 mph, using almost all of the first 3 gears, but with very poor traction (best 60' = 2.24), and hence poor ET's.

Now in an effort to finally get my car to hook at the track and use all 4 gears, I picked up (among other things) a moser 12-bolt rear. The rearend is used and comes with 3.73's. After looking at theoretical mph using gear calculator, if I understand correctly, it seems seems running a 3.73 gear would have me just shifting into 4th (1:1) before crossing the traps, whereas if I ran a 4.10 gear, I could use more of my 1:1 gear in the 1/4. So my question is, are the 3.73's going to hurt me that much to the point where it would be worth it to swap them out for some 4.10's or will it not make that much of a difference? Is there a better choice other then the ones I'm considering? Maybe there's something I'm not taking into consideration that I should be?

Also, once I get better and run consistant with my car N/A I'd like to maybe add a wet n2o kit, should this be a factor when chosing gears too?

Thanks.

 

Unless your trapping above 125mph, go with the 4.10s. Above that, 3.73s(3.90) or a taller tire.

 

I would stick with 3.73s if I were you. Especially considering your traction issues and your future plans. If you put 4.10s in, you're going to need to make your car hook to make it worth it, but if you add a big shot of nitrous, etc., you may also start wishing your 4th gear was a little longer. Since the 12 bolt already came with 3.73s I don't see the point...

 

If you definetly go N20 stay 3.73 with a 26inch tire but if you stay N/A you will need a 4.10 with a 26inch tire or 4.10 on juice would need a 28inch tire.

with your higher than stock reving setup and your current gear is the reason for your low mph because you are not using your 1 to 1 gear at all.

 

I was trapping at 113-115 at Napierville and 112-113 at Sanair with my 4.10/4.11s near the end of 4th,I have more or less the same set up as you do.

I get 1.80 60ft though,maybe get good tires and try it out before changing gears because you will be up the creak once you hit it with gas you will nead a lot bigger tire.

Switched over from M6 to A4 at the end of last season,will be in Napierville all month of April trying to get used to the new set up,if you are there come and chat!!!!

 

4.10