Best Differential

[Guest Andrew]

Since i had that little encounter with the curb i've decided the next thing i'm getting is a LSD.

What did the 325is get on it? I don't want mine to tall, something around 4.10 or even 3.7 ish with a good amount of lock .. perhaps 50 - 60 %.

Do any BMW diffs fit this spec?

[Guest coka]

wot would be the effect after getting the LSD??...big difference?..

i have no idea..is LSD limited slip differential?...i hears that somewhere...i think the E46 m3 advertisment or somthing.

[dave 2]

go group buy on the lsd i say..... im keen

[Guest Andrew]

http://auto.howstuffworks.com/differential.htm

for those who doesn't know how a diff works..

[E30-323ti 66]

If you want a 3.7:1 you'll need the ring and pinnion from an auto E36 325i, and a LSD centre from a E36 325/8is (dunno if the autos came with a LSD).

What ratio do you have at the mo Andrew??

My 323i has a 3.46:1 I think!?!?

[Guest Spargo]

the Sport's came with a 3.73:1 to 1, which is nice, but for better acceleration you'll want a 4.41:1 diff from a 318is. This was a small case diff, sdo you'll have to transfer the internals from it to a big case diff.

All the BMW diffs have a 25% lock, any higher, and you'll have to find an Alpina diff, which has a 40% lock.

[Guest Andrew]

I think my stock diff is .. either 4.10:1 or 3.7ish:1

I think probably i'll go for the 3.73:1 LSD from the 325is. Since i'll want a bit of top end when I pop the new motor in.

Has any one put the M coupes rear diff cover on thier E30 diff? Helps a lot if your an autocrosser. There is a good article on e30sport.net on how to do it.

[E30-323ti 66]

CLiK WuRM, I don't think the small case to big case internals are interchangeable.

You can increase the lock-up of a stock LSD, you need to pull it all apart and add extra shims to increase the preload on the clutch plates, best left to the pro's I'd say.

I'll be looking for a 3.73:1 LSD in the near future, the 3.46 is a little tall with the toyota G/box, 70 1st, 125 2nd, 180 3rd, 230 4th, 300 5th.

You wouldn't want to get carried away overtaking with gears like those.

[Guest Andrew]

so the e30 lsds are clutched diffs? I always thought they were viscosity based.

[Guest Spargo]

Yea, my bad, they ain't. What i meant to say was that you can buy conversion kits to make your 3.73 big case lsd a 4:41 lsd.

[E30-323ti 66]

As far as I know they are Clutch type LSD's.

Later model 3 series (M3's, Z3 etc..) have TORSEN type LSD's.

[Guest Andrew]

As far as I know they are Clutch type LSD's.

Later model 3 series (M3's, Z3 etc..) have TORSEN type LSD's.

did e36 m3s have torsen?

[E30-323ti 66]

The 3.2l ones may have??

You could get a Quaife, only $1900+GST, ouch.

Andrew: If you are sticking a M50 in it and eventually a later model G/box you may find a taller diff (or your stock one) may be good as some of the later boxes have a 1:1 5th, thats why they have diff ratios like 3.25:1 etc...

[Guest Andrew]

I'm not sure what the m20 gearbox is.. 4th 1:1 and 5th overdrive?

Due to budget constraints i'll probably use the m20 box till it dies.. those m50 units aren't cheap