Wich differential to use?

[serg]

Hello, I am trying to figure wich differetnial would be easeast (direct swap) or actually fits an 89 535IA, have access to a 4.47lsd off a 735I and a 3.15 off a 750I. Also if not a direct swap what work needs to be done, I would prefer and try the 4.27lsd to gain more acceleration, I think? thanks, Serg

[shogun]

this might help you
http://www.vinesauto.com/diffratio.htm

[Tiger]

Some did this... he converted auto trany into manual... and had 4.27 differential... gearing is so short that car jumps but the RPM at cruising speed is kinda high. Talks to Vines Auto... they know their stuff by reputation.

[Rigmaster]

750i diff will not work- it's the large case diff, you need the medium case diff. Any E34 6 cyl (except M5) or 530i diff will be a direct swap, as well as the E32 6 cyl (735/i/il)- but keep in mind that the input flange on the E32's and the Manual E34's is larger than the input flange on the auto E34's- so you'll need to swap that out with a new crush washer and torque to the correct spec- or the diff will whine like 632Regal.


FYI, your 89 535iA should have a 3.91 diff in it now, so going to a 4.27 would not be too much of a jump- IMHO. Especially considering that BMW put that ratio in the later 535iA's - got one in my wife's 91 535iA and it really scoots from a standing start and does not seem to wind out too many RPM's at highway cruising speed. You would probably not want to go with the 3.15 if you're looking for better acceleration- as that would have the opposite effect. (besides the fact that the diff from the 750il would not work in your 535iA...).

That 750i diff would be a direct swap for the M5/540i and the V8 E32's like 740i/il and other V12's like 750i/il.


Bret.

[632 Regal]

that was a bad trip, so tight you couldnt turn the thing. No new crush washer for me but lok tite on the pinion nut.

o you'll need to swap that out with a new crush washer and torque to the correct spec- or the diff will whine like 632Regal.