LSD info wanted

Thu Aug 30, 2007 7:18 pm

my alpina lsd needs some new clutch packs, you can jack it up on one side and turn the wheel quite easily

This is probably explained by a hero who owned it in the past and added the british racing club sticker on the windscreen!

Thu Aug 30, 2007 7:44 pm

Simon
would you perhaps know what diff my C1 would have as it appears to be revving very low in top gear

Thu Aug 30, 2007 9:18 pm

does it have the dogleg box or normal overdrive?

Fri Aug 31, 2007 3:46 am

fastdiablo wrote:
Simon13 wrote:my alpina has a factory fitted 3.73 lsd and it's a 2 door. It's defo the rarest of the the ratios for a 325.

I thought........all facelift manual 325i saloons 2/4 door had a 3.73 diff/ LSD or not. Auto saloons had 3.64. All tourings/sports had 3.91's whether they were auto or manual. Chrome bumper wagons bar the sports had 3.64's too.

Cabs i don't know about!
So the way im reading this, if i havent got lsd at the mo, im best off changing it for a std ratio 3.91 for fun and trackdays ? . . .

so would a 3.91 be a small or large case, and are they the same size, i know, that sounds stupid ? . . .

I think wat im asking is if they would both use the same length drive shafts also how do i know if i got small or large case at the moment ? ? ?

sorry, im starting to waffle but im sure you get the idea . . .

Fri Aug 31, 2007 7:23 pm

3.91 is the bigger diff fitted to 325's

316,318,318iS,320 all use the small case diff, only M3's and 325's came with the bigger casing diff.

Small case diff has 6 bolts holding the backplate on i believe? a 325i diff has 8

All half shafts are the same for all E30's whether they have abs rings or not is the only difference in them. ABS standard on 325's and M3's an option for all other models.

Props are all the same so if you decide to fit a big diff into a 318iS then this is no problem

hth

Fri Aug 31, 2007 8:49 pm

Simon13 wrote:does it have the dogleg box or normal overdrive?

its got the normal (stiff)shift pattern
sorry to highjack the thread

Fri Aug 31, 2007 8:54 pm

probably a 3.64 i'd say

next Q, is the car in 5th at 70mph doing 2500rpm? thats a 3.64 on a standard H change box in top

Fri Aug 31, 2007 9:07 pm

i think its a tad higher than that but still well under 3000 ,been a while since i've driven her

Sat Sep 01, 2007 2:05 am

bigkev wrote:
Simon13 wrote:does it have the dogleg box or normal overdrive?
its got the normal (stiff)shift pattern
sorry to highjack the thread

my apologies too cos i hijacked this thread aswell . . . but, Si, while i have your ear, I was talking to a guy who raced an e30 in a one make series, but now racing something and was talking about lsd's.

He was talking about tuning them to lock at different torques by changing to a different clutch pack ? is this something thats commonly done, are clutch pacs readily available or are they a racer only mod (read expensive) ?