3.46 diff swap?

[spikeisgr8]

The only downsides to a Torsen is that when the wheel comes OFF the ground completely, it behaves like an open diff. This is usually only encountered in high performance race cars, usually on slicks.
Otherwise, the Torsen is much better for lack of maintenance (No clutches to wear out. A clutch pack doesn't really last more than 50k miles. It slowly becomes a full time open diff.) Heat is also not a problem.

Thanks for the info! It definitely seems like more people have gone for the 3.73 ratio (partially because E30 diff vs. Z3 diffs were more readily available/affordable years ago when the Z3M came out IMO). I was leaning towards the 3.73 since my car is just for pleasure on the weekends, and because I thought it'd make more sense to use a clutch pack type diff as it is now. But when I think about it, most people running 3.73 appear to have larger wheels/tires, while I'm running on stock wheel set up. So, those with bigger wheels/tires are probably more comparable to a 3.64 because of that. And based on what you said about clutch pack LSD's not lasting more than 50k miles, what's the point of buying one with almost triple the mileage as mine if it won't work as intended! I'll admit, the only reservations I have in regards to the Torsen diff is whether or not I'd run into that problem with the speedometer pulse generator (I'm basing this on what I read from Ron Stygar's thread 15 years ago when he changed his diff to a 3.46). And my second concern is if by going with the Torsen, will it change the handling characteristics of the car that I'm so used to already. While I do not track or auto-x the car, I don't mind turning DSC off and kicking out the rear end when I make a turn from a stop at a light (I mean who doesn't, right!?). I'd hate to lose the ability to easily do this. I'd image the Torsen would not affect this and would only be noticed by driving this car through turns the way it's meant to be driven that, admittedly, I do not get the chance often enough on the local roads I travel.

[JoshS]

It's not hard to keep the inside rear wheel on the ground, even on a race car though, unless you have a LOT of power. Use a light (or no) rear sway bar, and a big front sway bar, and there will never be any wheelspin.

[Tazmanian Devil]

Talk to Jonathan at Thayer motorsports. https://redirect.viglink.com/?format...rsports.com%2F

When I rebuilt my rear, I used his 40% lock-up kit. He may have exactly what you want. He may even have a rebuilt rear waiting to be shipped to you.

[spikeisgr8]

Alright, I'm resurrecting my thread rather than starting a new one. I got the 3.64 diff installed today. It is everything I thought it would be. It wakes the car up TREMENDOUSLY in EVERY gear. I actually use 5th gear now instead of just on the highway. Definitely recommend. A lot more shifting, but you're always right in the sweet spot of the power band. However, I've discovered that my speedo is not calibrated correctly. I used the speed sensor thingy from the 3.64 diff instead of the one that came with the 3.15, which from what I read, is what I was supposed to do. But using my GPS, it appears the speedo is reading about 8-9 mph too high. I know, stock, it was reading 3-4 mph too high, but this is too much! Do you guys have any suggestions?