Which 320i Diff???

[Guest Anonymous]

I am installing a 320i close ratio 5 spd and am trying to determine which LSD to use. Does anyone know the part numbers or on which car I should look? What I am asking is: When calling around to wreckers what year and model 320i should I ask about?

[Guest Anonymous]

I believe they were offered only from 80-83. Still, it is hit or miss whether the car has one. A lot of the time it is hard to tell whether it is an "is" car or not. You want to ask them if the diff has an S stamped on the side (see pic). If it is still mounted on the car, then turning the wheels should make the opposite wheel turn in the SAME direction. Removing the rear cover, you should see a cylinder next to the main gear, as opposed to a square full of gears (see link for pics).

Here's a link to one on eBay: 320i LSD

Also check the diff faq at bimmers.com

[Guest Anonymous]

As i have understand, 80-83 diff have the waky 25% limitation, older ones, rare then, have the 40%, they are easier to modify...a 25% lsd in a midly modified car is a waste of money, more if it is used, unless you use the car in winter

The 25% that i am presently modifying is now tested at 85lbs of torque to breake it, so now it is a 70%, with some additives, it can be a 80% i think. No it is not in the car yet(next week i hope!!)

[Guest Anonymous]

80 or newer S3.91 gear ratio if you have a close ratio trans you may suffer on the street but what fun on the track