S2.93 with 3 Disk Not Locking

[Wanganstyle]

S2.93 with 3 Disk Not Locking

40ft/lb is close to spec. I doubt there is any thing wrong with the unit if it is not making weird noises. An unequal limited slip will yield different results from a left and right turn. You can't compare to your e36 because you probably have different tires and suspension setups. To help with your wheel spin, try to loosen your rear sway bar. You really need to understand how it works on the road. It is important to keep both wheels in contact with the pavement and how to input power. Too much power will actually make the LSD less effective.

A new Oem Lsd in a e30m or 325is will lock up and smoke 2 tires

The same 188mm zf 25% 2 plate Lsd is used in the e32 735i-5 speed manual and mine would do figure 8 doughnuts.

A the same unit was used in the e36m3 and if new or not worn out they will also do figure 8 doughnuts


On the track it’s a different story; the local track to benchmark with is Buttonwillow and the corner is club corner; if you are driving it correctly you’ll be flat out and the inside rear drive tire airborne. 2 plates will wheelspin, 3 plates will wheelspin, 4 plates if setup correctly will not.

This is data from actual testing on street legal 100-200tw tires with actual street cars and global time attack cars and nasa st4 cars.

[dsphil]

Hey guys, looking for some advice here. I recently installed the Thayer motorsports 3 disk clutch setup in my S2.93. After the first ~25 miles of easy driving and wide turns the breakaway torque was measured at abt 60ft/lbs at the right rear. After a few weeks, I did a hard 2nd gear pull and snapped a cheap rear cv (car is S50 powered) and coasted to a stop. Fast forward to my next track event at Palmer motorsports park and the cars is almost coming to a stop on the hard uphill left hander because its spinning the inside wheel so bad. I re-measured the breakaway torque and I can barely get my wrench to click at 40ft/lbs. Is there a chance my new friction disks are spent? Maybe the Belleville washer isn't preloading it enough? Any other thoughts? I did contact Theyer and the got back to me quickly saying that is seemed to be acting normal. I find this hard to believe since I recently drove an e36 M3 on the same track and just drove right through that same turn with no spin at all. Thanks in advance for any feedback.

40ft/lb is close to spec. I doubt there is any thing wrong with the unit if it is not making weird noises. An unequal limited slip will yield different results from a left and right turn. You can't compare to your e36 because you probably have different tires and suspension setups. To help with your wheel spin, try to loosen your rear sway bar. You really need to understand how it works on the road. It is important to keep both wheels in contact with the pavement and how to input power. Too much power will actually make the LSD less effective.

[e30davie]

Thankyou for posting it. Wasn't so hard was it:)

[JGood]

https://workshop-manuals.com/bmw/3_series_e30/325i_m20_sal/2_repair_instructions/33__rear_axle/11__final_drive_with_cover/1_ra__replacing_both_bearings_on_final_drive_housing_(type_m)_final_drive_removed_-/

Sections 11, 12, 13, and 14 will likely be relevant.

[Wanganstyle]

S2.93 with 3 Disk Not Locking

Lol, get off your high horse.

Get high and stop complaining.

There is no link; find the bmw technical document like any bmw tech would

[e30davie]

Lol, get off your high horse.

[Wanganstyle]

Do you have a link to this?

Spoonfeeding.com

[e30davie]

BMW has an entire TIS dedicated to the e30 differential and LSD internal service.
I suggest you read what the BMW factory published first before messing around asking the interweb for halp.

Do you have a link to this?

[dsphil]

I am no expert in lsd. Since you have the 3 disc setup and inner wheel slips during hard left turns, have you try hard right turn? My thought is that you have unequal limited slip with the 3 diac setup and cause one side to wear out faster than other side. Can you compare the breakaway torque on each side and report back.

[Wanganstyle]

Cliff notes:


1. OP is troubleshooting and looking for ideas and knows that most likely the friction discs are damaged


2. The parts came with a very detailed installation procedure that also matches multiple other DIYs found on this forum and others


3. Wanganstyle must have done this 100's of times but clearly does not state what to measure and why the spacer plate (standard in all 188mm diffs) that was the only part removed in the process could cause a problem since Theyer clearly accounts for this when selling a standardized setup.


4. The only other thing removed during installation of this kit is the output shafts and the end plates with the seals to remove the lsd unit from the housing. Each end plate has its own specific shim that was kept with its respective plate for re assembly. The LSD unit is a simple stackup of parts.

5. Clearly Wanganstyle didn't read the post because I stated that the static breakaway torque was 60ft/lbs after I broke it in and after a broken axle and a few track days it was barely 40ft/lbs


6. Wanganstyle has added deep insight to this thread about the internal workings and negative repercussions of DIY modifications to the BMW 188mm differential by stating, "use oem parts and pay an expert".

If you don't measure what came out and what went in then you are at the garbage in garbage out #1 infinite loop.


BMW has an entire TIS dedicated to the e30 differential and LSD internal service.


I suggest you read what the BMW factory published first before messing around asking the interweb for halp.

[DTFE30]

Cliff notes From original posters (your) thread

1. Op installed set of parts that is supposed to be wonderful and work. Op didn’t measure anything

2. Op drives magic muffin top product and it doesn’t work

3. Op posts to complain and then argues that products installed and experience is not crap.

4. Reality hits

Cliff notes:


1. OP is troubleshooting and looking for ideas and knows that most likely the friction discs are damaged


2. The parts came with a very detailed installation procedure that also matches multiple other DIYs found on this forum and others


3. Wanganstyle must have done this 100's of times but clearly does not state what to measure and why the spacer plate (standard in all 188mm diffs) that was the only part removed in the process could cause a problem since Theyer clearly accounts for this when selling a standardized setup.


4. The only other thing removed during installation of this kit is the output shafts and the end plates with the seals to remove the lsd unit from the housing. Each end plate has its own specific shim that was kept with its respective plate for re assembly. The LSD unit is a simple stackup of parts.

5. Clearly Wanganstyle didn't read the post because I stated that the static breakaway torque was 60ft/lbs after I broke it in and after a broken axle and a few track days it was barely 40ft/lbs


6. Wanganstyle has added deep insight to this thread about the internal workings and negative repercussions of DIY modifications to the BMW 188mm differential by stating, "use oem parts and pay an expert".

[Wanganstyle]

S2.93 with 3 Disk Not Locking

Are you saying the Thayer products are garbage? The install didn’t require any changes in clearances. You simply remove the spacer and put an extra friction disk and dog plate in.


Sent from my iPhone using Tapatalk

Cliff notes From original posters (your) thread

1. Op installed set of parts that is supposed to be wonderful and work. Op didn’t measure anything

2. Op drives magic muffin top product and it doesn’t work

3. Op posts to complain and then argues that products installed and experience is not crap.

4. Reality hits



And yes; knock off products are garbage. Bmw doesn’t use crap and give shit for directions

[DTFE30]

Garbage in garbage out.

Using lower grade than Oem components with random guessing at clearances =...... not that great results.

Buy a new aftermarket Lsd unit; or get parts from BMW/Porsche that are genuine zf and have someone who knows the units well build it all

Are you saying the Thayer products are garbage? The install didn’t require any changes in clearances. You simply remove the spacer and put an extra friction disk and dog plate in.


Sent from my iPhone using Tapatalk

[DTFE30]

How bad did you drive it after the axle snapped?

Have you drove the track before the diff was gone thru?

I only really drive it to and from the track. I didn’t get a chance to test it before the axle snapped.


Sent from my iPhone using Tapatalk

[Wanganstyle]

Hey guys, looking for some advice here. I recently installed the Thayer motorsports 3 disk clutch setup in my S2.93. After the first ~25 miles of easy driving and wide turns the breakaway torque was measured at abt 60ft/lbs at the right rear. After a few weeks, I did a hard 2nd gear pull and snapped a cheap rear cv (car is S50 powered) and coasted to a stop. Fast forward to my next track event at Palmer motorsports park and the cars is almost coming to a stop on the hard uphill left hander because its spinning the inside wheel so bad. I re-measured the breakaway torque and I can barely get my wrench to click at 40ft/lbs. Is there a chance my new friction disks are spent? Maybe the Belleville washer isn't preloading it enough? Any other thoughts? I did contact Theyer and the got back to me quickly saying that is seemed to be acting normal. I find this hard to believe since I recently drove an e36 M3 on the same track and just drove right through that same turn with no spin at all. Thanks in advance for any feedback.

Garbage in garbage out.

Using lower grade than Oem components with random guessing at clearances =...... not that great results.

Buy a new aftermarket Lsd unit; or get parts from BMW/Porsche that are genuine zf and have someone who knows the units well build it all