Diff Ratios.....What's best???

[Brew]

no, but with more torque coming from the engine, you don't need the extra mechanical advantage from say a 4.10 LSD anymore.

It all depends on the type of driving you do. An M50 isn't going to cause traction issues except for maybe in 1st gear, so if you don't do a ton of highway driving it might be worth going with the 4.10lsd.

My car was a blast with the stock 318 4.10, but it didn't last too long with the S50 and welded spider gears.

[KangamangusDriver]

I ran a E36 325IS trans with a 3:25lsd diff

Very civil for highway driving and rather quick off the line.
Very good combo for highway and in town driving.


I hear the E36 M'Guys get reall horny over the 3:43lsd

[japspecvr6]

i got a m52 and 3.73........i think imma change it too a 3.25.......the 3.73 runs gears out to fast........

[Mr.SWISS]

What cars had the S3.46?

[whakiewes]

I have driven a variety of M50 swapped cars with various diffs; 2.93(?) to a 4.10. I have found that there are a few things to take into consideration. A bone stock M50 that redlines at 6500 is going to be much less friendly with diffs than an S50 at 7250rpms and another 70hp. Transmission also takes into account a lot, overdriven 5th or not.

I really like the feeling of 2-4th in a 3.73/4.10 equipped car. If you concerned with gas mileage then a 2.93 or 2.72 (?) might be your better choice. My favorite thus far for a mildly equipped M50 is an E36/7 3.23. I am sure an E30 3.25 would be equivalent and probably cheaper. It gives the best all around accelleration.

I am collecting diffs for my swap. Since LSD's for E30's are relatively cheap to obtain, easy to install, and an effective way of gaining performance, I can keep an array of them for my swap. I really love toying around in a 4.10LSD but 1st and 2nd are nearly a joke. A 3.73 flies through gears as well, but better appointed than the 4.10. A 3.23 to me is the best for a daily though as you will have enough power to get performance from the lower gearing, and also save on some gas when you'll only be at about 2900 at 60 in 5th.

3.23 I think would be your best bet, or 3.25 if you have a source. I know I can swap my 3.73 in a heart beat for a 3.23.