Hotwired

I would like to know if 3.90 gears are legal in SCCA ASP class and would they have a low gear whine in first and second?

Thanks.

PushinTheLimit

Someone else more knowledgeable can come in here to correct me if I'm wrong, but I'm pretty sure that gear changes are not legal for ASP. That would put you straight into SM2. That's why the C6 Z06's in ASP have found that they either are topping out in 1st gear, or bogging in 2nd on courses.

ltborg

You can only change to factory available C5 ratios, since all C5s are on the same line in the SCCA Solo Rulebook. Basically if you use the factory parts your choices are:
GU2 Axle, Rear, 2.73 Ratio
GU6 Axle, Rear, 3.42 Ratio
G90 Axle, Rear, 3.15 Ratio
so the 3.90s would not be legal.

PushinTheLimit

I guess that is the updating/backdating of the rules on the gears. But I doubt that you really would want any of the other gear ratios for autoX except for the 3.42's. They seem to work pretty well for the C5Z crowd.

Z06Fix

The stock M12 tranny combined with the 3.42 rear, makes for almost perfect gearing. Most courses I can put the car in 2nd and forget it. There have been a few tight turn arounds where grabbed for 1st, but they are rare.

Racin Jason

No, they are not legal for Street Prepared. You would go into SM2 or prepared class.

They do make a huge difference. My car transformed completely when I put 4.10 gears in.