To LSD or not to LSD.... 318is questions

[BenjaminButtton]

So I recently had my car ('91 318is) up on my buddy's lift, and realized that when I spin one rear wheel, the other rear spins the opposite direction, and this would indicate that my diff is open, correct? I've questioned it before when attempting to spin a cookie or try to play racer boy, my inside wheel will spin up like with an open diff... Now aren't all 318is E30's sposed to have LSD 4.10's...?
Maybe I'm mistaken, please correct me, I still have a lot to learn about these cars. I would be fine with the open diff if I didn't plan to drive the car in the winter, and being in MN rear wheel drive cars need all the help they can get.
SO, my queston is, is it definitely an open diff, or is it a broken LSD that could be fixed?
Thanks in advance. Here's the numbers on the diff, they're kinda hard to make out, iphone pics...





And here's the car to paint a better picture.

[jlevie]

The "stock" differential is always an open type, but certain models (is/es) came with an LSD or it could be included in the build as an option. There should be a tag on one of the rear carrier bolts that will state the ration and whether it is a limited slip. Som LSD's also has an S painted on them.

[ForcedFirebird]

LSD was an option on the 318is, it was standard on the 325iS and eS.

As Jim said, look for a tag hanging off one of the bolts of the diff cover - it will probably have to be scraped/sanded to make out the numbers, I have only seen one 318iS come in the shop with factory installed LSD, and we have about 100 e30 clients.

[BenjaminButtton]

The "stock" differential is always an open type, but certain models (is/es) came with an LSD or it could be included in the build as an option. There should be a tag on one of the rear carrier bolts that will state the ration and whether it is a limited slip. Som LSD's also has an S painted on them.

LSD was an option on the 318is, it was standard on the 325iS and eS.

As Jim said, look for a tag hanging off one of the bolts of the diff cover - it will probably have to be scraped/sanded to make out the numbers, I have only seen one 318iS come in the shop with factory installed LSD, and we have about 100 e30 clients.

Thanks guys. I looked for a tag when I was under there but it seems to be missing, I'll look again though just to be sure. Didn't see any signs of the painted 'S' either. So its probably safe to assume its open then?

My buddy's 318is has a LSD and I guess we both assumed they both had LSD's for some reason. Oh well I guess, might be time to weld it up... I will probably end up swapping in a 3.73 LSD eventually. (Friend has one he will give to me) From what I've gathered it doesn't make the already slow car THAT much slower...

[_lestat_]

Place your car in neutral and put the rear wheels off the ground.
If you turn one wheel, the other must follow with an lsd.
If a second person can counterturn the other wheel, you will have an open diff.

[irish44j]

If you have the diff out of the car, there may also be an "S" painted on the top of the case. At least there was on mine...kind of a stenciled "S".

Could also be that someone swapped the diff at some point, for some reason.

[frankie591]

The clutches in my 3.73 lsd were so worn that the diff afted like an open diff. When I swapped lsd's, I made some plates that bolt to the flanges so I could test the breaking torque of the diff, and my stock diff held 5 ft-lbs before breaking free :D