lsd help''''

Post Thu Dec 04, 2014 6:41 pm

hi guys.....iv looked and read a few post on here about lsd's...
im more confused than ever now!!!..lol.... im used to old ford's which are easy compaired to e30's it seems....
right iv got a 320 face lift 2dr manual... so i believe i have a small case 4.10 open diff????.....iv bought a welded diff but looking at it and speaking to a few people this insn't a good idea for a car mainly to be used on the road....iv also got a 2.5 engine to fit i'll be using the 320's original gear box.... so getting back to my question what are my lsd diff options???....
are a medium case and large case the same????....both wont fit my rear beam.....new to bmw's so still learning....thanks guys...

Post Thu Dec 04, 2014 7:35 pm

Welcome to the world of e30's lol Ive been in a similar situation regarding diffs and ratios so may have more info, med case diffs or 188 dogs as there called shuld bolt streight onto your rear beam but not 100% sure it will match the driveshafts so someone might correct me on that I think it will, as for lsd units there are lots about in various ratios so depending on what you want depends on what you get the 4.10 will be good for take off but bad on top end likewise a 3.07 for example would be slower at take off but better for motorway miles I seam to recall z3 diffs and compact diffs fit too

Post Thu Dec 04, 2014 7:42 pm

There are only two sizes of diff fitted to an E30, small and large, self explanatory

But as BMW diffs come in three sizes overall a lot of people refer to the large E30 diff as a 'medium' as there is a larger diff in the range which was never fitted to E30's

Post Fri Dec 05, 2014 9:16 am

As above, there is the 168mm case, the 188mm case and the 210mm case.
E30s only use 168 or 188 cases unless the rear end has been converted.

Post Thu Dec 11, 2014 5:14 pm

so what are my lsd options?....straight fit or a bit of fetling to make fit????....

Post Thu Dec 11, 2014 5:38 pm

http://www.e30zone.net/e30zonewiki/inde ... fferential

Ben

Post Fri Dec 12, 2014 11:10 pm

This gearing calculator at this website will help you choose the ratio you want, just feed in your tyre size, diff ratio and gearbox ratios and it will give you RPM's in each gear and the miles per hour per 250rpm. cheers.

http://diffsonline.com/bmw-differential ... ation.html

Post Sat Dec 13, 2014 1:09 pm

Your 4:1 diff will give 65mph at 3000rpm.

Medium case diff's came in 3.64,3.79 and 3:93 ratio's.
3:64 gives 73mph at 3000rpm.

Finding a s/h LSD that does what it says on the can will be your main issue!

320i gearbox will work fine with an ex 325i engine,ratio's are almost the same as the ledgendary 'sport' 'box.Use the 320i prop,it's adjustable to accomodate either diff case size.