LS1 rear diff dual ear

[apiazza2010]

Thanks WanganStyle, Garret and everyone else.
I am rebuilding the LSD unit as per the Bmw TIS and, since I did my Ls1 swap using Garret's kit I am also using his rear differential mount (which fits perfectly!)

I had to redo the two metal pieces that attached to the body as the were not long enough, but thats probably because my diff is lowered for clearance for the driveshaft joint.

WanganSyle, Spot On!!, I always wondered why my left wheel was burning out the whole time, now I know

[Wanganstyle]

The subframe mounts are brand new, Solid Condor mounts, the diff bushing was shot. I now replaced it and will be doing second mount today.
Hopefully it will fix some of the issues I have been having
Does an LSD behave like an open diff when it's shot? As in if i'm burning one tire much more than the other, does that mean my diff clutches are toasted?

See if your LEFT (usa driver side) rear tire is bald. This is common on high miles E36 M3's - the LSD dies and the left rear tire gets all the torque is = bald because its always spinning.


When the factory BMW LSD unit wears out it becomes an open diff; you can do doughnuts clock wise with an Open diff BMW or a dead LSD bmw. You wont be able to do counter clockwise doughnuts with a bmw open or dead LSD.

Why is the car able to do doughnuts clockwise with an open?

1. BMW has close to perfect 50%/50% weight balance
2. the LEFT (usa drivers side) of the differential is favored; the unit has the ring gear on that side and the driveline is also asymmetrically installed in the chassis
3. clockwise doughnuts allow the left wheel to be on the outside and drive the car in a circle, counter clockwise puts the left wheel inside and just spinning (car wont rotate)

Miata's and RX7's can also do clockwise doughnuts only with open diffs. (due to same reasons 1/2/3 above)


if you want to solve this problem (LSX engine+ stock e30 diff) the solution is built LSD unit and diff+ garret TVS mount for ear #2; otherwise things will wear very very quickly.

[CLM21]

I would have. That sikky stuff is wayyyyyy nicer than any shit I could put together lol.

And you can buy that second ear mount for Garrett... the guy who posted it lol.

[Q8y_drifter]

If i can fab and weld, i wouldnt have bought a 3K swap kit :)

[shiboujin]

Make one? If you're putting that much power down, you should be using solid mounts anyway. I've put 500whp through my all aluminum mounted single ear without issue and will continue to do so until it blows up.

[Q8y_drifter]

You need one of these .....

Where can we get one of these?

[The Dark Side of Will]

I've heard of E30's starting to kill that body mount starting at about 300 RWHP. The dual mounting ear setup eliminates the problem.

[garretvs]

You need one of these .....

[jalopi]

this'll be the first i've heard about e30s having frame issues, though i guess there's a first time for everything. pics will be appreciated

[Alpina]

E30 have a weakness in the construction,, ab


if you have a powerful engine ,, you will break the upper frame in the body where the diff bolts to the ear,,, this is well known on E46 M3,,, E36 M3 evo and on ALL Euro Z3 ///M roadsters,,,,,,,

i had S38B38 ,, and one day the car was almost sliding around to much,, when flooring and playing in corners,, the frame was broken ,, and we made a reconstruction to the ear,, another plate and welded the floor bottom in the trunk,, from under neath



this is oem .. i will try to take a picture and show the difference

[DER E30]

Get an open diff and weld it...:devil:

[shiboujin]

well remember, if you've toasted the inside, the diff is probably 100% shot. You'll likely need a whole new LSD. The dog ears can/should be replaced, but the mating surface to the center section is what melts and fubars. Kinda like replacing your pads but not replacing the rotors.

[apiazza2010]

I got new bushing for everything, all Condor UHMW, and I should receive the LSD clutches in the next few days.
I also have 18k rear on BC Coils.

Thanks for the advice everyone!

[shiboujin]

If you're on LS power and have the factory diff, well yea. You're going to destroy the innards. It will act like an open if the clutches are shot.

My setup is solid aluminum bushings for subframe/diff and 75D for the trailing arms. GC coils. 18k rear springs.

[jalopi]

maybe, that could explain your issue