E30 Zone

Hey guys,

I'm looking for a 3:46 Diff for my E30. It has a E34 535i engine in it. If any of you have one or can make any suggestions cause the current 3:64 is way tooo revvy which I am not a fan of.

Thanks in advance.

I think that 3.46 was M3 only,so expect to pay M3 tax.

Drop Gareth a PM,he not only repairs/re-builds/modifies diffs but also runs an M30 engined touring so will be in a position to offer informed advice.

What ever you do,do not fit a small case diff,the oil capacity of these seems to be woefully inadequate to keep them cool when used with a big or tuned engine...

M3 was 3.15, 3.46 are very rare, 3.64 should be okay though.

I spent ages looking for one and then sold it

i thought 323's had a 3.46 they would be the most likely source.

ImysE30 wrote:M3 was 3.15, 3.46 are very rare, 3.64 should be okay though.

I spent ages looking for one and then sold it

Will a 3.15 fit? Is it a single mount?

What you are looking for is a medium case diff with a more suitable ratio,your 3.64 will be a medium case one and this is a popular ratio so will sell on to fund it's replacement.

Similar diffs can be found under some E28's,but you will need to swap the output flanges and possibly the back plate as well.Be aware that some E28 versions were fitted with the large diff,also shared with 7 series models of a similar age,and these will not be an easy fit.

daimlerman wrote:What you are looking for is a medium case diff with a more suitable ratio,your 3.64 will be a medium case one and this is a popular ratio so will sell on to fund it's replacement.

Similar diffs can be found under some E28's,but you will need to swap the output flanges and possibly the back plate as well.Be aware that some E28 versions were fitted with the large diff,also shared with 7 series models of a similar age,and these will not be an easy fit.

The guy that sold me the car told me a dif from a late model compact or Z3 should fit... What kind of money am i looking at for the diff and labour separately..

I have a Z3 2.8 diff in E30 use. As far as I remember, it was a direct swap.
Ratio is 3.15 (IIRC) and it's a torsen slipper.

Brianmoooore wrote:I have a Z3 2.8 diff in E30 use. As far as I remember, it was a direct swap.
Ratio is 3.15 (IIRC) and it's a torsen slipper.

What rear Z3 mate would you be ale to give me full details so I can start my search.. What are the rpms like at the top end on the motor way? I have a e34 535 sports straight 6 in mine, do you see any compatibility issues there?

ImysE30 wrote:M3 was 3.15, 3.46 are very rare, 3.64 should be okay though.

I spent ages looking for one and then sold it

M3's are 3.15 for the evo3 and 3.25 for the rest (euro models).

I have a 3.64 in mine and I had to buy an open diff and swap all the internals as I just couldn't find a 3.64 lsd.

Got a 3.38 here from a Compact if any use?

I've got a 3.46 LSD with 50% lock up and tightened plates on my m50 touring, had it made by a guy called kevo on here.

The prices were very good, you provide the LSD and he will rebuild it to what spec you want.

swali wrote:

Brianmoooore wrote:I have a Z3 2.8 diff in E30 use. As far as I remember, it was a direct swap.
Ratio is 3.15 (IIRC) and it's a torsen slipper.

What rear Z3 mate would you be ale to give me full details so I can start my search.. What are the rpms like at the top end on the motor way? I have a e34 535 sports straight 6 in mine, do you see any compatibility issues there?

It was a UK spec. Z3 2.8 - thats all the details I know about it.
I'm using it with a direct 5th (e36) gearbox, not an overdrive 5th (E30) gearbox, and it's a little revvy on motorways for my taste, but not excessively so. It's about the equivalent of a 3.9 with an overdrive box.