BMW E30 318IS - Tring to find out if it has LSD

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Jamiestrutt
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Post Thu Aug 27, 2015 10:39 am

I have a build sheet from bmw and I don't know if in the description if it says it has a lsd. Apart from doing the obvious wheel spin to try and see I was thinking of other options as it's not drivable at the moment.

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pacerpete
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Post Thu Aug 27, 2015 11:13 am

Contrary to internet folklore, VERY few IS had a LSD fitted new. Easiest way is to jack up one side at the rear and see if you can turn the wheel. If the jacked wheel moves freely, you have an open diff or a VERY worn LSD . If you can barely move the wheel, you have a LSD.
There should be a metal tag attached by one of the rear diff cover bolts with the ratio stamped on it. A LSD will have a 'S' before the ratio. Be aware that this is not conclusive as a lot can happen in 25 years ! I have come across several diffs with tags that do not relate to the diff ratio and plenty with tags missing completely.
HairyScreech
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Post Fri Aug 28, 2015 7:57 pm

Sorry Pete but I am yet to find a non-rebuilt E30 diff that is capable of making the wheel feel stiff.
Pretty much every E30 LSD now falls into the "VERY worn LSD" category.

I'm yet to check but I think even the 15 years younger one on my Z3 will also count as fucked. :?

Take the back plate off, confirm it is/isn't an LSD, start saving for a rebuild.
2.8 development thread http://www.e30zone.net/modules.php?name ... c&t=170822

m3.3.1 m20 thread - now running, chip needed - any volunteers?
http://www.e30zone.net/modules.php?name ... =viewtopic&
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TriggerFish
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Post Fri Aug 28, 2015 10:52 pm

HairyScreech wrote:Sorry Pete but I am yet to find a non-rebuilt E30 diff that is capable of making the wheel feel stiff.
Pretty much every E30 LSD now falls into the "VERY worn LSD" category.
Is there any way to test wear? Or is it a visual inspection only with the back plate off?

I've not driven my car far, so I'm not 100% what the LSD does (in terms of how it acts, rather than what it does), but it's defo got an LSD, and you can feel it locking up...
hennared323i
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Post Sat Aug 29, 2015 7:22 am

iirc the "life" of a brand new slipper is/was something like 10 minutes before wear set in
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bosers
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Post Sat Aug 29, 2015 8:31 am

I've read that the breakaway torque from factoryis 65ft/lbs applied to the hub nut. A worn one prob a lot less.