Lsd/Diff experts, Please come in

Post Sun May 04, 2014 9:46 pm

Right, if you are faced with two options, which one would you choose ?

1- Lsd Diff from E24 635i (3.64 ratio) (Medium case 188mm)

or

2- Lsd Diff from E34 525i M50 engine (3.23 ratio) (Medium case 188mm)

Also, My understanding is:

for the 1st option just change back cover ?

for 2nd option, swap e34 diff internals into e30 diff in transmission workshop ?

They are going in 325i M20 Manual car

Much Appreciated

Post Sun May 04, 2014 9:53 pm

You wouldn't want a 3.23 in any E30 with the standard overdrive fifth gearbox. 3.64 is a good choice, but still veers towards economy rather than performance.

Post Mon May 05, 2014 12:00 am

Brianmoooore wrote:You wouldn't want a 3.23 in any E30 with the standard overdrive fifth gearbox. 3.64 is a good choice, but still veers towards economy rather than performance.

Useful info thanks Brian, its coming from e24 so am i right with just swapping the back cover?

Post Mon May 05, 2014 12:14 am

Id of put money on an E24 635i diff being a large case as it 210 size.

Post Mon May 05, 2014 12:22 am

leeparkes wrote:Id of put money on an E24 635i diff being a large case as it 210 size.

Is it rare to see a medium case on 635i ?

this is the picture what I am being offered (whole rear axle)

https://www.dropbox.com/s/e0vnij5eghhn1 ... 20diff.jpg

Post Mon May 05, 2014 9:29 am

Thats a 210 diff, useless to your 325i

Post Mon May 05, 2014 12:38 pm

DanThe wrote:Thats a 210 diff, useless to your 325i

Ok scrap that idea then

Will the e34 lsd fit?

Post Mon May 05, 2014 12:46 pm

E34 can be rebuilt into an E30 case, but it'll make your car drive like a 1.6 with those ratios.

You can't do an LSD on the cheap. Find 400 quid and buy the right one from a trader on here.

Post Tue May 06, 2014 10:26 pm

I have an S3.46 diff for my e30 that came from a 635 e24. Just swap the back cover and axle flanges.

Post Wed May 07, 2014 12:27 am

e30rapidic wrote:I have an S3.46 diff for my e30 that came from a 635 e24. Just swap the back cover and axle flanges.

Do you know how to measure the diff size ? 188mm etc

I might get the seller to measure it and save me the trip to know if if its a medium case or not

Post Wed May 07, 2014 12:51 am

Easiest way to check is to count the 13mm hex head bolts on the sides of the diff (not the driveshaft flanges themselves). Small case diffs have 4 bolts, medium case diffs have 6 bolts, large case diffs have 8 bolts.

You can also count the backplate bolts but some of these can be hidden so often mis-counted... yes people can really be that daft!