differentail

[318lotis]

i need new differentail for my e30 m42 318is, im planning trips to the salvage yard. what model year car should i be looking for? i just want a quite running diff., im on highway alot. whats a good year make and model to yank from?  thanks

[M5wanaB]

E30 318is has a uncommon diff. You could use out of a 318i or is from 90-91 or a 318iC from 90-93. The only other car with a small case rear is a 318ti. Good luck the ti might be your best bet as it is newer but people drive the hell out of those things. I would look for one out of a convertible with low milege.

[DesktopDave]

I was looking for a post somewhere with all the diffs.  Couldn't find it.

Any e30 diff will bolt right in.  The six-cylinders usually have medium case diffs, they fit directly in our car.  They're far more durable but about 20 pounds heaver.  I'm told the Z3 diff will also work, but they're very rare in the yards.  I'm pretty sure you can also grab an M50/M52 e36 diff, but you'll need to swap the rear cover to fit in your car.  If you absolutely require a small case, look for the M10 318i.  They're rare but have suitable diffs.

Avoid any e30 eta's...they have very short diffs, usually in the 2.73 range.  That'll kill your acceleration.  I'd avoid the late 90's 318i auto 'vert.  I think it had a 4.27 or something crazy like that.  The later auto 325i & iS had a medium case 4.10.

I pulled a 3.73 LSD from a 325is that is a good match for our M42.  It's awesome on the highway.  3.64 would be a good bet too.  The e28 M30 cars have 3.15's IIRC, a bit low but that might work out if the price was right and it's an LSD.

You're likely aware of the tag on the rear with the ratio stamped on, but they're always rusted.  Check to see if the output flanges spin the same way when you spin the input...that'll be an LSD.

[YetiX]

Look on Craigslist for a 4.1 limited slip. I see them all the time around here. You can also contact a local shop for help locating one.

Where are you located?

[318lotis]

thanx for your suggestions, im in the Louisville ky. area and finding slews of e30's..
so if anyone lives in this area, ther is a ton of e30 stuff around..

[deekay]

some 6-cylinder Z3s had medium-case torsen differentials that bolt up- you just have to swap over the e30 rear cover. i have one in 4.10 in my car and with "street/sport" springs and some good meaty tires it is fantastic... always finds a way to put the power down.

i got mine from jordan @ lone star auto in TX, for about the same price i see used clutch-types go for. find him on e30tech and shoot him a PM.

[YetiX]

Yeah, I should have mentioned that mine's a medium case too.  I figured with the massive amount of torque my M42 puts out, I needed the extra strength!