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brian_s
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Sat Oct 26, 2024 11:29 am

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?
Last edited by brian_s on Mon Oct 28, 2024 9:05 pm, edited 1 time in total.
Corasdad
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Sun Oct 27, 2024 7:31 pm

Contact spanner rash on youtube think he had a spare
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brian_s
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Mon Oct 28, 2024 9:08 pm

Corasdad wrote:
Sun Oct 27, 2024 7:31 pm
Contact spanner rash on youtube think he had a spare

Thanks, seems like finding parts is getting difficult!
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flybynite
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Tue Oct 29, 2024 1:19 pm

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
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brian_s
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Tue Oct 29, 2024 3:13 pm

Forgot about the z3! Although do they not use a different type of lsd rather than the plated diff of the e30?
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flybynite
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Tue Oct 29, 2024 6:17 pm

brian_s wrote:
Tue Oct 29, 2024 3:13 pm
Forgot about the z3! Although do they not use a different type of lsd rather than the plated diff of the e30?
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 :thumb:
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brian_s
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Thu Oct 31, 2024 3:46 pm

flybynite wrote:
Tue Oct 29, 2024 6:17 pm
brian_s wrote:
Tue Oct 29, 2024 3:13 pm
Forgot about the z3! Although do they not use a different type of lsd rather than the plated diff of the e30?
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 :thumb:

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 :D
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flybynite
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Thu Oct 31, 2024 5:25 pm

brian_s wrote:
Thu Oct 31, 2024 3:46 pm
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 :D
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 :thumb:
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brian_s
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Thu Oct 31, 2024 8:18 pm

flybynite wrote:
Thu Oct 31, 2024 5:25 pm
brian_s wrote:
Thu Oct 31, 2024 3:46 pm
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 :D
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 :thumb:
Oops missed out!! The search continues :mad:
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flybynite
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Fri Nov 01, 2024 1:01 pm

brian_s wrote:
Thu Oct 31, 2024 8:18 pm
Oops missed out!! The search continues :mad:
Prices have softened a bit but you still need to be quick with rare bits. Nothing wrong with a Z3 torsen (one going in one of mine) but they are not ideal ratios for a standard car.
rix313
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Sat Nov 16, 2024 7:02 pm

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.
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