LSD advice

[lysergicsurfer]

I just recieved my tax refund for the year and I thought I would give my Ti the much needed LSD. I have researched these differentials all over this forum and all over the internet but I am still a little fuzzy on how to know where the diff came from, if it bolts up,.. etc. I am looking for a 3.73 to 3.45 and I think I have found two good diffs reasonably priced.
http://cgi.ebay.com/ebaymotors/BMW-3...1%7C240%3A1318

http://cgi.ebay.com/ebaymotors/BMW-E...1%7C240%3A1318

Are either of these good deals? Will they bolt on and/or what else would be needed to complete the swap? Anyone ever have any luck buying a diff off ebay? Any help would be great, Id like to order one soon!
Thanks for helping.

P.S. Anyone know of any LSD's for cheaper?

[spidertri]

Both of the diffs you linked will work. The rear end of the ti is the same as the E30 rear end so naturally the differentials will be compatible as well.

The first diff is a medium case from a 325is and the second a small case from a 318i. The stock diff on the ti is a small case, however, the medium will also bolt up and is recommended if you are doing a 6cyl swap. A lot of people recommend swapping in the E30 half shafts along with the differential so that the geometry will be correct when/if you lower your car.

[lysergicsurfer]

Ok I couldnt figure out if they were medium or small, so I thank you for clearing that up!!
Becuase of that I think I will have to go with the stock size and its close to the stock ratio anywayy. So with the 3.64 small cased lsd would I still need the e30 half shafts? Btw my car has a H&R Race/koni setup, so I definatly do need the half shafts then? and why? And would that be everything I need? I might order tomorrow so I dont want to forget anything and sorry for asking soo much! I probly wont get more hp out of this car and I am on a limited budget so I dont want to have to do anything I dont need. Thanks for the advice, I cant wati to have an LSD..


Anyone out there have a 3.64 lsd? How do you like it? Any pros and cons?? I would rather have the 3.45/6 of course but this is my cheapest alternative.

[FMD]

The E30 small case diff you posted will work, but you have 2 options.

Use the diff as it is but will need E30 half-shafts (not sure if the ABS detection systems are identical or not) to bolt up. or...

Retain your stock half-shafts but swap the output flanges, seals (going to need new seals ~$40 from the dealer), and flange retainers from your stock diff into the E30 diff. You might have to re-shim your output seals to set the right amount of backlash, etc.

[1996 328ti]

Originally Posted by spidertri

A lot of people recommend swapping in the E30 half shafts along with the differential so that the geometry will be correct when/if you lower your car.

I don't think geometry has anything to do with it. The medium size diff is physically larger. I also have my ABS sensors shimmed a bit.

[spidertri]

Originally Posted by 1996 328ti

I don't think geometry has anything to do with it. The medium size diff is physically larger. I also have my ABS sensors shimmed a bit.

Oh, from what I understood about the stock shafts vs E30 was that with a lowered car the stock shafts would be parallel to the ground, so that if you went over a bump or something there wouldn't be any "play" in the shafts.

With the E30 shafts, they would sit at an angle to the ground like this --->/[]\ (not realistically but for instance) so if the car hit a bump and the wheels went up relative to the diff there would be some extension room for the shafts. Again, that was only for cars with a significant drop.

[Dan I]

Output flanges on the E30 diff are larger than the input flanges on the ti half shafts. Like mentioned earlier, get E30 half-shafts and put a couple washers under your abs sensors. You can mess round with trying to swap flanges and cv joints and whatnot from E30 to your ti shafts, but it's cleaner, faster, easier, and cheaper to just get E30 shafts. Decent E30 shafts can be had for $20.

I purchased my 3.73 from the guy selling the 3.64 you linked...I'd buy from him again. 3.64 would be perfect...

BTW, DON'T try to take the diff flange bolts out with female allen sockets. as me, I know. Female Torx sockets are the tool for the job.

[angel318ti]

try to source a 3.45 lsd. I waited after doing my transmission conversion and found a 3.45 lsd with only 75K miles. It was just much simpler doing that than trying to swap output flanges and shimming the ABS sensor. Its just out with the old and in with the new.

[yoda]

The seller SERG was the one I bought mine from, an e30 LSD will bolt on...
KEEP IN MIND that you will need to buy e30 Half Shafts, and will need to change the Diff cover as well w/New Speed sensor. This is from My personal experience. I have yet to change my Diff Cover, but this is so you don't get the check engine light, you will read speed accurately but you will have a CE code because of the position of the speed sensor.
SO:
e30 LSD
Z3 Diff Cover and Speed sensor
e30 Half Shafts

Final Drive is up to you, if you have a manual you probably have a 3.45... so a 3.73 or 3.64 means a bit higher (200 to 300) RPM's, if you have an Auto like me it's a 4.44 and it'll be lower RPM's at highway speeds... I went from 3,500 @ 80mph to 2,800 @ 80mph with a 3.73.

[Dan I]

Diff cover and speed sensor? I never had a CE light after my diff swap. Anyone else?

[yoda]

Originally Posted by Dan I

Diff cover and speed sensor? I never had a CE light after my diff swap. Anyone else?

There are a few of us that got the CE light, and it is related to the speed sensor, I will try to replace mine with an M Roadster sensor and the e30 cover to see if that clears it, if not I will have to change the cover as well. The speed sensor for the ti is short an equilateral, the sensor I took out of the e30 diff was longer and had one side longer than the other. I had to use the ti's sensor cause the e30 sensor had a different plug, but from what I've seen the sensor for the M Roadster is similar to the e30's and has the same plug as the ti's.
I will be crossing my fingers to see if that fixes it!...

[1996 328ti]

Never had a CEL due to a speed sensor.
3:46 Quaife with M Coupe diff cover and E30 shafts.

[FMD]

There needs to be more clarification between the small case and medium case when making reference to E30 diffs.

[spidertri]

Small case came on 4cyl E30s, medium case on 6cyl E30s.

[Bluebimma]

I used an Mcoupe finned diff plate, E28 LSD medium case, ti shafts and have ran stock, FK automotive, and 318is Intrax lowering springs without any issues.