[buster-riley]

I am thinking about a Wavetrac LSD and maybe a gearing change. What would be sensible gearing for a stock engine MT car that is mostly 99.9% street driven daily driver, but lightly autocrossed, 1 or 2 track events a year. I am keeping the car forever. Thx

[dradernh]

Originally Posted by buster-riley

I am thinking about a Wavetrac LSD and maybe a gearing change. What would be sensible gearing for a stock engine MT car that is mostly 99.9% street driven daily driver, but lightly autocrossed, 1 or 2 track events a year. I am keeping the car forever. Thx

Based upon your profile, I wouldn't change from the 3.08 ratio you have now. These cars' torque levels solve the gearing issues that would be present in an NA car. That was the approach I took, and except for autocross I'm using my car the same way you are. If you were to get more serious about autocross or track use, you might want to lower the gearing as long, as it was still acceptable to you on the street.

I got my Wavetrac from Dan Fitzgerald at diffsonline.com. While I was already pretty sure the 3.08 wouldn't need to be changed (I used the gearing calculator on Dan's site: http://diffsonline.com/images/GearingCalculator.xls), I asked him what he thought based upon my running three track days a year with the rest being street use. Dan recommended staying with the 3.08.

Dan knows this stuff inside and out - it might be worth contacting him for more specific advice.

Update: Here's another online gearing calculator, from Tunnell Racing. This one has an advantage over Dan's calculator in that you can edit it: http://www.tunnellracing.com/gearcalc.xls . I used this capability to add a graph to make it easier for me to see what the RPM drop would be when shifting at different RPMs.