rear diff questions???

[bloxsom]

i was wondering what gears are in the 1993 325is?
would it be worth it to drop in a 1995 m3 auto rear diff?
could i feel a difference and are there any down sides to this besides top speed??
thanks
chris

[BadR1]

This is on another tread right now. If you have a stick and are going to the M3 diff out of a auto. It will make a huge diffrents. You will have a much better acelleration, but the trade off is worse gas milage and a high rpm cruising speed, and like you said lower top speed, so if you do mostly town driving its great.

Long road trips would get drawn out enless you get a 6 speed trans then they work awesome.

[bloxsom]

i figured that.
does any one know what rpm i will get with a 5 speed, and a 1995 auto m3 diff at 70?
thanks

[bimmerboy328i]

You have a 3.15 in your 325. The M3 auto's I belive were 3.38 or 3.91. I know a 3.73 diff tops out at 120mph.

[BadR1]

M3 autos are most likly 3.91 since thats what most autos have 328 and so on the M3 will have a lsd though. Well it depends on how tall of a tire you will be running too, you need to fastor into the mix. but I would say like 3.5k plus

[bloxsom]

i think the 3.38 are in obd3 auto m3s and up
and 3.23 in obdl
i would have 17" tires with a 3.23
isnt there a chart ware you can plug all this in and it will give you the rpm
thanks
chris

[beatniks325]

correct,
95 auto E36 M3 has a 3.23
96-99 auto E36 Me has 3.38

that's why auto Mer's switch in a 3.91 LSD if they can find one from an auto 325

[Spahrman5]

http://diffsonline.com/techinfo/index.htm