LSD?

Post Fri Dec 28, 2012 5:12 pm

Does anyone know if there's a way of finding out if your car has a LSD without sliding underneath the car on a cold, wet concrete floor? The tag on the diff' has rotted. I'm hoping for an online model chart telling what's got what. BMW are usualy well documented.

Post Fri Dec 28, 2012 5:15 pm

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

Scroll down

Post Fri Dec 28, 2012 5:36 pm

Thanks. I've seen the wiki chart & my 90 325 cab can have a LSD..........or not! So I'm none the wiser. I'm going to change the fluids on the car & the LSD oil is a different spec' to the ordinary diff'.

Post Fri Dec 28, 2012 6:22 pm

It'll only have an LSD if it is a Sport if you go by that guide, so is it a sport or not? Easiest way to check is to jack the rear, spin one rear wheel and see which way the other turns. If it is the same direction it is an LSD, if it is the opposite direction, Open.

Post Fri Dec 28, 2012 6:31 pm

FinalD wrote:It'll only have an LSD if it is a Sport if you go by that guide

Any E30 could have an LSD from new if the buyer wanted it. The Sports had them as standard, but it wasn't just the Sports that had them.

Post Fri Dec 28, 2012 6:37 pm

Thanks. To the best of my knowledge it's not a sport. But when I had the back end up on jacks & run the car, for another problem, both wheels spun in unison. I've run the back wheels on my e46 in a similar manner. Then only one wheel rotated fast, the other slow. It's this that made me question my car.

Post Fri Dec 28, 2012 6:44 pm

jmc330i wrote:
FinalD wrote:It'll only have an LSD if it is a Sport if you go by that guide
Any E30 could have an LSD from new if the buyer wanted it. The Sports had them as standard, but it wasn't just the Sports that had them.

Hence saying 'if you go by that guide'

it's much more likely that a cab will have an open diff, not an LSD though imo.

jmec wrote:Thanks. To the best of my knowledge it's not a sport. But when I had the back end up on jacks & run the car, for another problem, both wheels spun in unison. I've run the back wheels on my e46 in a similar manner. Then only one wheel rotated fast, the other slow. It's this that made me question my car.

Don't run the engine. You need it in neutral and spin the rear wheel yourself. They will turn in the same direction if you run the car as how else is it going to go forwards?

Checking the speed isn't a very good way of doing it to be honest. Check the rotation direction for a much more accurate indication as to the type of diff.

E: Grabbed this from another thread but it will help if the car is standard/original...

BenHar wrote:And here: https://shop.bmw-classic.de/is-bin/INTE ... AUTOMOBILE

Enter VIN and search then click the options tab.

Ben

Post Fri Dec 28, 2012 7:12 pm

FinalD wrote:
jmc330i wrote:
FinalD wrote:It'll only have an LSD if it is a Sport if you go by that guide
Any E30 could have an LSD from new if the buyer wanted it. The Sports had them as standard, but it wasn't just the Sports that had them.
Hence saying 'if you go by that guide' it's much more likely that a cab will have an open diff, not an LSD though imo.

Stupid phone, some of my post was missing.

I went on to say the guide is only useful to find what a car might of had from new, but even then its not great as any car could have any option ticked. And for a 20+ yr old car, anything could happen - my 318i is now fitted with a medium case 3.91 LSD, definitely not on the options list from BMW.

As you say, the spin test is the easy way.

Post Fri Dec 28, 2012 7:23 pm

Yeah, that's the 'problem' with old cars really, it could well have been specced without (or equally with) one and by now have one (or not) for any number of reasons. The only way to know for sure is to test or take the back plate off, but the second option is messy and more hassle than it's worth.