Identifying a Z3 diff

Post Thu Apr 17, 2008 7:27 pm

As above, there is no ID tag like an E30

Anyone got any idea's?

Post Fri Apr 18, 2008 2:27 pm

Anybody?

Post Fri Apr 18, 2008 6:41 pm

Ok, no part numbers or nothing, should have done this from the start

1- Measure ratio = 3.38:1
2- Remove back plate and inspect = Torsen slipper!!

Post Fri Apr 18, 2008 6:44 pm

are they any good these torsen diffs ?

Post Fri Apr 18, 2008 6:50 pm

No idea. I noticed the only Z3 they dont fit them to is the M

Post Fri Apr 18, 2008 6:52 pm

strange.So what do they use in the m ? An e30 m3 diff maybe ?

Post Fri Apr 18, 2008 7:10 pm

I would expect so, or maybe the larger 210 type that the E36 M's use

Post Fri Apr 18, 2008 7:27 pm

i didnt think the e30 based z3 back end would take the e36 diff though ,as BMW would have used all E36 open diffs

Post Fri Apr 18, 2008 7:55 pm

I was told the Z3M uses a 3.15 torsen diff which is variable ie up to 100% lock up.

Post Fri Apr 18, 2008 8:57 pm

I noticed the part number on mine is not on the M list

Z3M - http://www.realoem.com/bmw/showparts.do ... g=33&fg=15

Z3 2.2 - http://www.realoem.com/bmw/showparts.do ... g=33&fg=15

Notice the M slipper is cheaper!

Post Fri Apr 18, 2008 9:08 pm

The 3.15 Z3 M diff on the later cars is a torsen type. Hence the different part number to the earlier 3.15 clutch type diffs. Incidentally, the US forums share the same confusion as we do. They can't understand why E36 diffs don't fit the 'E36' Z3!

Post Fri Apr 18, 2008 9:47 pm

Why is it that the LSD unit is a different part number to the regular Z3 then?

They are also torsen

Post Sat Apr 19, 2008 9:20 am

No idea.. but you will have to change the diff cups unlike i was saying before (they are closer to the diff than an e30 diff) Still need to do mine.

Torsens are alot smoother than the e30 lsd, plus there are no clutch packs to wear, it's all done via gears. They act like a normal diff ie you cant tell they're a slipper unless you pull the cover off. (No idea mine was a slipper till we got it home ands pulled the cover.)

Good find and great in a big conversion!!

Post Sat Apr 19, 2008 11:21 am

oze30 wrote: Torsens are alot smoother than the e30 lsd, plus there are no clutch packs to wear, it's all done via gears.

You got one on your conversion then?

Post Sat Apr 19, 2008 1:42 pm

DanThe wrote:
oze30 wrote: Torsens are alot smoother than the e30 lsd, plus there are no clutch packs to wear, it's all done via gears.
You got one on your conversion then?

yeah. LOVE it. just wish it was a different ratio!

Post Sat Apr 19, 2008 10:14 pm

Hows it feel compared to a standard slipper then?
Looking forward to 'testing' mine out

What ratio is it, and what are the gear box ratios like?