OEM BMW LSD Mechanism?

[FMD]

So the stock oem bmw lsds come with a 25% lock using 2-clutches. Does anyone know the mechanism that the stock lsd uses, 1-way? or 2-way?

I thought the lsd would come from the factory with as a 1-way diff (safer?), but from the pics in this thread:

http://www.e30tech.com/forum/showthread.php?t=44131

The ramps look symmetric, implying a 2-way lsd design from the factory? I take it this is why Kaaz doesn't offer a 2-way lsd for BMWs but only 1.5-way.

If this is the case, shouldn't the oem diff be "ok" or for drifting barring the crap 25% lock rate, and relatively "amazing" for drifting with a 80% lock rate or higher (more clutch plates)?

[mattmartindrift]

you are correct, it does look to be a 2-way. I know that the Mitsu. Starion also uses a factory 2-way diff.

25% lock rate isn't bad. It just means the wheels slip more in turns. It's designed that way for street tires with realatively low adhesion to the road. However, in drifting because of the almost symetrical load, you should be okay.

If you have the time and resources, a better-locking diff. can make a night and day difference in entries and switchbacks/transistions, etc. etc.

[protomor]

sweet! didn't know that. explains a few things though.

[vdshenoy]

Cool...when my drift project car is done, I plan to drift till I blow up the factory LSD, and then weld an open one locked and use it till I can afford a real diff with 4 clutches.

Edit: Turns out my diff was an open one after all - welded it locked and I'm ready to rock and roll.

[FMD]

A worn-out factory lsd will effectively turn into a regular open / non-lsd over time.

[rpm620]

yup im just going to rock a OEM LSD untill its dead or just weld an open diff...

[bmwcrazi24]

im running a 3.73 lsd from the factory, and not that mine is quite worn out, however i have noticed under certain conditions it likes to over heat, and slip quite considerably. So i traded my buddy his open for my lsd...seems like i got the bad end of that deal but i couldnt find a 3.73 open for the life of me!

[tEckniks]

A worn-out factory lsd will effectively turn into a regular open / non-lsd over time.

lol i know. i love my open diff now

[mattmartindrift]

real diff with 4 clutches.



that's cute.


mine is an 18-plate diff.


there really needs to be someone making reasonably-priced diffs for BMWs.

[JDJordan]

and thats never going to happen. for this reason alone, I am thinking about going back to 240s. but for now I run a welded 3.91... much better than the oem lsd ha.

[jone30]

Why is a welded 3.91 much better? I mean, you can order different thickness clutches from various places online, different bellevue(?) washers, you can have the housing machined to accept one or two more clutches, etc. etc. Hard part is actually pulling the housing apart without stripping those little allen head bolts.
Oh, and I am glad someone is getting some decent use out of LS-unit tear down I documented.

[mattmartindrift]

isn't there another differential someone could swap in, like a Nissan R200 that has a TON of aftermarket support, and is super strong?


I know Honda S2000 guys used to swap in Nissan R200s.

[tptrsn]

isn't there another differential someone could swap in, like a Nissan R200 that has a TON of aftermarket support, and is super strong?


I know Honda S2000 guys used to swap in Nissan R200s.
Got any leads on where one of those could be obtained for a good price Matt?