Rear diff for M52 swap

[Bakea012]

Hello,

just wonderinf if i could fit rear diff from 325i with zf box and e36 prop?

thanks

[Motorhole]

It will all fit, sure. But you'll be doing, like 5000rpm in 5th at 70mph!

Using zf 'box and prop, you really need a final drive ratio of between 2.93 and 3.25. E30 325i's are 3.73 and 3.91 iirc?

Use a diff from a 6-cyl Z3 or E30 M3...I think there are some others that will work too, but can't remember off the top of my head.

[Bakea012]

Ok Brilliant thanks mate

[Bakea012]

i do need 325i diff output flanges though?

[Motorhole]

I think it depends on what car you're putting it into? I'm not sure whether or not 325i output flanges fit the half-shafts of the 4-cyl cars. I'm sure somebody else will be able to confirm

[HairyScreech]

Pretty sure all E30s have the "large" flanges, it was only with the e36 compact an Z3 4 pot did the small flanges come about.

[Bakea012]

Oh ok so if I had a diff from z3 6 pot it would mate up to 325i drive shafts easy enough?

[HairyScreech]

That's a direct fit.

It is what I have on the back of mine.

[TheMeathead]

I've just changed my gearbox/diff setup as my g240 shat itself. So I've fitted a g5s e36 box and compact 3.38 diff. The hubs from my small case diff fitted straight in and bolted straight to my driveshafts.

[HairyScreech]

Yep, that's small case to small case, direct fit.

You could also have used a rare compact or z3 medium case an used it whole with its stock output hubs/cups.