eb02z06

iTrader: (18)

My car is a 02 Z06, supercharged D1SC 644/541 rwhp/tq. Car has gone a best of 10.60@133 so far. Now I'm still using the the stock 3.42 gears and the M12 tranny that Z06's come with. Iv'e asked about switching gears to something lower like 3.73's or 3.90's but the have been told to not to or the car will be useless on the street. Well I don't care what the car does on the street-it's what it runs at the track. I run on MT ET streets that are 26x11.5x16. MT says the tires are 82" in circumference-but I measured them at 12psi and I got 84.75". So right now at 133mph i'm only at 5633 rpm, if i jump to 3.73 that's only 6177, 3.90's is 6458. Car weighs 3440 full race weight. At this power level if everyhgting was perfect the car should be able to trap 139mph. Now with 3.42's that's 5918rpm, 3.73's that's 6454 rpm and with 3.90's that's 6748. Now it's going to take some really quick shifting to acheive that mph and I dfon't powershift-just to save my tranny. I alos don't launch my car by side stepping it at 6000. It's usually a quick blip to 3000 and a quick release to get a 1.61 sixty. Since the M12 is spaced so tightly in 1st and 2nd( 2.97/2.07) you spend alot time in 4th going down the track-so wouldn't you want a gear that helps get things moving quicker? Also centri cars don't make torque like turbo's so-there more rpm dependant like straight motor-which like gears. What are your thoughts?

Packy

iTrader: (11)

How did you measure the circumference of your tires? If you had them off of the car then it probably wasn't correct because it was not under the weight of the car.

Gary Z

This fact alone says you need a higher ratio. 3.73 is the safe choice - 3.90 is the hardcore choice.

CamTom12

iTrader: (1)

I run 4.22's on the street... why would 3.90's be an issue?