E34 535i LSD, large case/small case

[Coltwee]

I've a friend who's doing an M30 conversion on his 325i sport, he has everything connected up to his sport diff. He's looking to change it to a lower ratio 3.46 or 3.64

The car he bought for the conversion (E34 535i sport) is still sitting and has a LSD in it, hes not sure about sizes of diff casings and whether it would fit or not. I had heard that no e34 diff would fit into the e30, just looking to get a definitive answer before he goes messing about!

Could anyone help with pics of the different casing sizes?

And if looking for a 3.46 or 3.64 diff what car would have the correct size casing?

[monkey]

think the 535 diff is the large case one and no good for an e30

[Coltwee]

Thats what I thought, any ideas on alternatives?

Is an M3 diff to low a ratio for the M30 (3.25?)

[leeparkes]

3.46 is apparently the best all round diff for the M30.

[charlE30]

3.46 is apparently the best all round diff for the M30.

Certainly is, some say the M3 3.25 is to long (better for top end, but acceleration suffers)

I'm using a 3.91 LSD at the mo and it is a bit short but then all my driving is on back roads. On the motorway it's a killer sitting with revs at 3000rpm, good for overtaking as you don't need to drop down because your right in the powerband.

I think you can also use some of the E28 diffs by changing the back plate and output shaft thingimy jigs (don't know the proper term )

[Rav335uk]

Apparently you can swap the internals of the e34 diff into a large case e30 diff(8 bolts on the rear casingHTH

[Coltwee]

Apparently you can swap the internals of the e34 diff into a large case e30 diff(8 bolts on the rear casingHTH

Interesting, could anyone say if a 325i LSD would be a large case without seeing it?? Anyone done this before, or have any instructions?

Thanks!

[Rav335uk]

Its not easy, you need specialist tools to get it done mate, and a sport should be a large case diff.There is someone on here that does them but con't remember his name.Some one will be along who can give you his name.HTH

[Coltwee]

Ah right, well there is a local guy who is gearbox specialist, might get him to do it as long as I know the sport diff is big enough to swop the internals over ;)

Thanks again!

[monkey]

i think that e30s use a small case and a medium case diff . e34s use a medium case and a large case if you lsd is from a 535 it will be large case and wont fit in to an e30 diff . if you had 525 lsd it would fit in to an e30 diff but only the larger one used in e30s .

[DanThe]

Apparently you can swap the internals of the e34 diff into a large case e30 diff(8 bolts on the rear casingHTH

No you cant, the 535 diff is too big!! I went through this the other week and im sure you posted on the thread Rav

What monkey is saying is right

[Rav335uk]

So is it only medium e34 diff internals then

[DanThe]

Yes, eg - small (E30 4 pot) medium (E30 325i + E34 525i) large (E34 535i)

[Coltwee]

Yeah he lifted the Diff out of the E34 on Saturday, (burst his finger open in the process!) Took the rear plate off and the crownwheel(?) is about the same size as the 325i diff casing! No chance of it fitting.

So what cars did the correct sized LSD for the e30 come in (the 3.46/3.64 ratios)?

Thanks!!

[oakey]

^Mtech1 sports should have 3.64 lsd's. There is always a couple of tech1's being broken.

[e30_singh]

Whats wrong with using a 3.25 diff? I thought this was the diff for a M30 swap.

Did not realise it was the 3.64.

[leeparkes]

3.46 is supposed to be the best all round diff for the M30,but the 3.64 will give better acceleration.

[ImysE30]

What about a 2.93 diff?

[Rav335uk]

Too long, and no good for decent accelleration, but motorway cruising.I can honestly say,cause i got one, a 3.46 is the best all round.

[ImysE30]

I am asking because that is what blingsta said he has on his

[leeparkes]

2.93 would be a bit loooong!

[ImysE30]

Cheers chaps

[Rav335uk]

Maybe he does alot of motorway miles

[ImysE30]

I'd assume so. Going to be mainly inner city driving for me