14 years later I’m putting the e30 back on the road and the one thing that is big on the list is a proper diff! More specifically a 3.91
I see prices have moved up significantly and things are harder to come by! Is there any one out there to ask or breakers to look for?
LSD
Moderator: martauto
You can use a Z3 one too, flanges may need swapping but more of them about. This one doesn't look bad. (no connection with the seller)
https://www.ebay.co.uk/itm/156482150219
https://www.ebay.co.uk/itm/156482150219
They use both types, but the Torsen tends to be 3.15 or 3.25 I am guessing the 3.91 is a plate type, but only way to be sure is take the back off. Torsen is not bad for road use and any plate LSD is likely to need a rebuild and new plates anyway. Beware of cheap ebay kits and 'snake oil' lsd conversions

flybynite wrote: ↑Tue Oct 29, 2024 6:17 pmThey use both types, but the Torsen tends to be 3.15 or 3.25 I am guessing the 3.91 is a plate type, but only way to be sure is take the back off. Torsen is not bad for road use and any plate LSD is likely to need a rebuild and new plates anyway. Beware of cheap ebay kits and 'snake oil' lsd conversions![]()
Have looked at that diff in the link and the seller states It’s a Torsen, there is pictures with the casing off, is there any tell tales you could see between the Torsen and plates diff?
Appreciate the help by the way

I missed the extra photos originally, no that is a plate diff, in fact it is not a common type either, it is a 1.5 way diff with asymmetric ramp angles (different on accel and decel) Not many about, I have one myself. you can tell by the 40 and 25 stamped on the carrier and a couple of other ways. Seems genuine but still may need a rebuild. Only thing I would say is these were originally built with no preload so many think they are not working if you jack the car up and spin the wheels.
It may have come from a Z3 but I have a feeling it was originally in something else
If you want a 3.91 I would get it bought

Oops missed out!! The search continuesflybynite wrote: ↑Thu Oct 31, 2024 5:25 pmI missed the extra photos originally, no that is a plate diff, in fact it is not a common type either, it is a 1.5 way diff with asymmetric ramp angles (different on accel and decel) Not many about, I have one myself. you can tell by the 40 and 25 stamped on the carrier and a couple of other ways. Seems genuine but still may need a rebuild. Only thing I would say is these were originally built with no preload so many think they are not working if you jack the car up and spin the wheels.
It may have come from a Z3 but I have a feeling it was originally in something else
If you want a 3.91 I would get it bought![]()

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I have a Blackline geared LSD in my road car and that's performed well. I fitted it before a european road trip earlier this year. The unit itself is about £600 + fitting but they are 'fit and forget' unlike plated diffs, which in an ideal world need to be opened up and serviced.