Any way to tell if M-Perf LSD is installed?

NandoM235 · 10-04-2019, 10:06 AM

My stock diff also has the etching in question.

babaikram · 10-04-2019, 02:17 PM

I am actually wondering myself. When my early 2018 m240i was in repair, I was given a replacement late m240i. Whilst the replacement m240i sounded worse with a very slow gear change, it felt more planted than my m240i despite being fitted with same sized Michelin Super Sport tyres

I ran the VIN of the replacement m240i and it did not have any fitted LSD, the car was minimally optioned anyway.

Does anybody know whether there Is any update on m240i. Or any other explanation for that matter

Luftwaffe1O1 · 10-04-2019, 06:07 PM

So my diff has the drexler logo and 1.2 just like the pic, but im pretty sure i have an open diff

Shovelman · 10-06-2019, 04:51 AM

My 2017 230 RWD 6mt has the logo also and 3.2 and probably an open diff.

The mystery remains.

Luftwaffe1O1 · 10-06-2019, 11:31 AM

Quote:

Originally Posted by Shovelman

My 2017 230 RWD 6mt has the logo also and 3.2 and probably an open diff.

The mystery remains.

Well the easiest way is turning on or off the dsc button to get it into dsc off mode. I notice a pretty big improvement in how much more planted the rear is with dsc off vs sport or sport +. Especially in straight line acceleration. So safe to say i dont have an LSD i think.

tadmcmichael · 12-10-2022, 03:31 PM

Going to resurrect this thread from the dead. I was also wondering if my new M235i had the LSD based upon how it drove and the fact that there were some other goodies installed that the seller was not aware of (Dinan CAI, M Perf muffler.)

My diff sports the "7599411" number on the top sticker to indicate that it is indeed an open diff. However, I don't get the same behavior that others describe. When it is jacked up in neutral, if I spin one tire forward the other side does not move and in one instance actually rotated forward like a LSD. For whatever reason, the normal LSD vs Open diff test does not behave as expected. Have others with the open diff tried this test?

JMcLellan · 12-10-2022, 04:26 PM

Quote:

Originally Posted by tadmcmichael

Going to resurrect this thread from the dead. I was also wondering if my new M235i had the LSD based upon how it drove and the fact that there were some other goodies installed that the seller was not aware of (Dinan CAI, M Perf muffler.)

My diff sports the "7599411" number on the top sticker to indicate that it is indeed an open diff. However, I don't get the same behavior that others describe. When it is jacked up in neutral, if I spin one tire forward the other side does not move and in one instance actually rotated forward like a LSD. For whatever reason, the normal LSD vs Open diff test does not behave as expected. Have others with the open diff tried this test?

I have a stock open diff from my M240 sitting in my garage. If you would find it helpful I could snap some pics of it and share to see if the tags and numbers and things look the same or different than what you have.

I had a heck of a time trying to answer this same question before I put the LSD in. Also, I didn't look at the LSD prior to it being installed to be able to compare. I wish these things were marked up to be obviously different. After noticing the improved drivability of the LSD I felt it was different but never confirmed by comparing the two parts.

tadmcmichael · 12-10-2022, 11:45 PM

Thanks. There seems to be a lot of confusion about this. Agree that this should have been much more obvious for the cars that added it. I think the 240 has different serial numbers than my M235. Not sure it would help me, but may help others.

dradernh · 12-11-2022, 08:25 AM

Quote:

Originally Posted by tadmcmichael

I think the 240 has different serial numbers than my M235.

M235i: https://www.realoem.com/bmw/enUS/sho...diagId=03_1127

M240i: https://www.realoem.com/bmw/enUS/sho...diagId=03_1127

JMcLellan · 12-12-2022, 08:23 AM

Quote:

Originally Posted by dradernh

M235i: https://www.realoem.com/bmw/enUS/sho...diagId=03_1127

M240i: https://www.realoem.com/bmw/enUS/sho...diagId=03_1127

Looks like the LSD for the 235 and 240 are the same part. Do we know if the stock open diffs are the same for both the 235 and 240?

freakystyly · 12-12-2022, 08:29 AM

Open diff for both ends in 9411. The m235i also had a 9412 listed and the m240i did not for some reason.

I'm not 100% sure but I think these diffs are bolted shut? Companies like diffsonline buy cores and do their magic to crack open the pumpkin and swap in their diffs, like wavetrac, quaife, etc.. so there is a possibility although slim.

aerobod · 12-12-2022, 09:11 AM

Quote:

Originally Posted by freakystyly

Open diff for both ends in 9411. The m235i also had a 9412 listed and the m240i did not for some reason.

I'm not 100% sure but I think these diffs are bolted shut? Companies like diffsonline buy cores and do their magic to crack open the pumpkin and swap in their diffs, like wavetrac, quaife, etc.. so there is a possibility although slim.

The welded diff component is the crown wheel to the differential cage. The LSD components are housed in a new cage that also supports the side bearings, so a new crown wheel or the original with the back face re-machined to remove the weld and add threaded holes, is normally used to attach the crown wheel to the cage.

JMcLellan · 12-12-2022, 04:51 PM

Here is the sticker on the top of my stock differential.

MAMSport · 01-25-2023, 01:00 PM

Quote:

Originally Posted by Feddersen

Lift the car so both rear wheels are air born. Turn one of them in one direction. If the other rear wheel turns in the opposite direction it is an open diff. If the other wheel stops or turns in the same direction it is a LSD.

Resurrecting an old part of this thread. Does the car need to be in gear for this test? I believe the car was in neutral (6 speed, RWD), but when I turned one wheel (I spun both rear wheels in both directions), the opposite side did not turn at all.

ggggbmw · 01-29-2023, 02:25 PM

The gear shift MUST be in neutral to observe the 'both wheels same direction' behavior. On an automatic, this is annoying to test as either the engine must be running to put it into neutral, or you have to use a wrench on the bypass mechanism to disengage the parking pawl.

This confused me for a while as I have the LSD, but I couldn't get the wheels to turn in the same direction. I was questioning whether that common bit of wisdom was actually correct until I finally clued in on the 'in neutral' requirement.

This is short dorky video of the difference in behavior, with an LSD, of being in park or neutral:

Sorry, don't have a video of the same behavior with the stock open diff.

MAMSport · 01-29-2023, 08:16 PM

Thank you very much!

romoguy15 · 01-30-2023, 09:51 PM

I am properly confused on this too and it's making my wheels spin. No pun intended. If I spin the wheel in neutral engine running, only one spins forward. The other side doesn't do anything. If I put it in drive with the engine running and spin one wheel, then the other side actually spins in the same direction.

romoguy15 · 02-04-2023, 12:53 PM

I went and did the burn out test and every time I did it, I had two tire marks. Guessing I do have LSD?

aerobod · 02-04-2023, 04:07 PM

You can get 2 tyre marks with a non-LSD diff due to the brake intervention when DSC or DTC is on or from the eLSD when they are off.

Another way to check is to see what preload the diff has if it is a plate type LSD. With the transmission in neutral and left rear wheel touching the ground and blocked to stop it moving (parking brake off), the right wheel is removed to expose the axle nut. Put a socket on the axle nut and use a torque wrench to measure the breakaway torque by gradually increasing the torque if it is a click type wrench until the axle rotates, or looking at the torque value when the axle starts to rotate on a beam type wrench.

The breakaway torque should be around 50Nm, but could be as high as 100Nm or so if it is the standard Drexler M-Diff LSD. Anything less than 30Nm would indicate no plate LSD or a need for a rebuild. Without this diff plate pre-load, even if you do have a plate type LSD fitted, it won't be very effective in stopping initial wheelspin.

10-04-2019, 10:06 AM	#23
NandoM235 Registered 0 Rep 2 Posts Drives: 2015 M235i RWD Join Date: Oct 2019 Location: Tampa FL iTrader: (0)	My stock diff also has the etching in question.
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10-04-2019, 02:17 PM	#24
babaikram M6GCComp, Porsche Cayman S PDK, Peug 208 GT1 BPS 512 Rep 1,280 Posts Drives: . Join Date: May 2015 Location: England iTrader: (0)	I am actually wondering myself. When my early 2018 m240i was in repair, I was given a replacement late m240i. Whilst the replacement m240i sounded worse with a very slow gear change, it felt more planted than my m240i despite being fitted with same sized Michelin Super Sport tyres I ran the VIN of the replacement m240i and it did not have any fitted LSD, the car was minimally optioned anyway. Does anybody know whether there Is any update on m240i. Or any other explanation for that matter __________________ Acceleration is heavenly
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10-04-2019, 06:07 PM	#25
Luftwaffe1O1 Lieutenant 230 Rep 555 Posts Drives: M235i, 2000 Z3 Join Date: Mar 2015 Location: San Diego, CA iTrader: (0)	So my diff has the drexler logo and 1.2 just like the pic, but im pretty sure i have an open diff
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10-06-2019, 04:51 AM	#26
Shovelman Lieutenant 243 Rep 525 Posts Drives: 2017 230i Join Date: Jan 2017 Location: Michigan iTrader: (0)	My 2017 230 RWD 6mt has the logo also and 3.2 and probably an open diff. The mystery remains.
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12-10-2022, 03:31 PM	#28
tadmcmichael Private First Class 80 Rep 168 Posts Drives: 2016 M235i Join Date: Aug 2015 Location: Atlanta iTrader: (0)	Going to resurrect this thread from the dead. I was also wondering if my new M235i had the LSD based upon how it drove and the fact that there were some other goodies installed that the seller was not aware of (Dinan CAI, M Perf muffler.) My diff sports the "7599411" number on the top sticker to indicate that it is indeed an open diff. However, I don't get the same behavior that others describe. When it is jacked up in neutral, if I spin one tire forward the other side does not move and in one instance actually rotated forward like a LSD. For whatever reason, the normal LSD vs Open diff test does not behave as expected. Have others with the open diff tried this test?
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12-10-2022, 11:45 PM	#30
tadmcmichael Private First Class 80 Rep 168 Posts Drives: 2016 M235i Join Date: Aug 2015 Location: Atlanta iTrader: (0)	Thanks. There seems to be a lot of confusion about this. Agree that this should have been much more obvious for the cars that added it. I think the 240 has different serial numbers than my M235. Not sure it would help me, but may help others.
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12-12-2022, 08:29 AM	#33
freakystyly Lieutenant Colonel 2982 Rep 1,796 Posts Drives: F22 B58 6MT Join Date: May 2016 Location: Ontario iTrader: (0)	Open diff for both ends in 9411. The m235i also had a 9412 listed and the m240i did not for some reason. I'm not 100% sure but I think these diffs are bolted shut? Companies like diffsonline buy cores and do their magic to crack open the pumpkin and swap in their diffs, like wavetrac, quaife, etc.. so there is a possibility although slim. Last edited by freakystyly; 12-12-2022 at 08:36 AM..
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12-12-2022, 04:51 PM	#35
JMcLellan Major 2041 Rep 1,178 Posts Drives: 2024 M2 Join Date: Mar 2022 Location: MN iTrader: (0)	Here is the sticker on the top of my stock differential. Attached Images __________________ 2024 M2 2019 M240i- Sold
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01-29-2023, 02:25 PM	#37
ggggbmw Lieutenant 433 Rep 442 Posts Drives: 2017 M2 Manual Join Date: Jan 2017 Location: Minnesota iTrader: (0)	The gear shift MUST be in neutral to observe the 'both wheels same direction' behavior. On an automatic, this is annoying to test as either the engine must be running to put it into neutral, or you have to use a wrench on the bypass mechanism to disengage the parking pawl. This confused me for a while as I have the LSD, but I couldn't get the wheels to turn in the same direction. I was questioning whether that common bit of wisdom was actually correct until I finally clued in on the 'in neutral' requirement. This is short dorky video of the difference in behavior, with an LSD, of being in park or neutral: Sorry, don't have a video of the same behavior with the stock open diff.
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01-29-2023, 08:16 PM	#38
MAMSport Second Lieutenant 87 Rep 264 Posts Drives: '13 128i M-Sport coupe Join Date: Apr 2016 Location: North Shore of MA iTrader: (1)	Thank you very much! __________________ E9x M3 front & rear suspension arms; BMW Performance brakes upgraded to drilled rotors in rear; BMW performance shifter; BMW Performance Exhaust; Wave Trac LSD with modified 'nannies'; BMW Euro Intake box; BMW Aluminum Strut Tower bar; ECS front and rear sway bars; 3 stage intake with BPC software; BMW style 78, 17 x 8" wheels with Bridgestone RE 980AS 225/45-17 tires; Koni Special Active struts/shocks, E9x M3 RTABs.
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01-30-2023, 09:51 PM	#39
romoguy15 Enlisted Member 5 Rep 38 Posts Drives: 2020 X3 M Sport Sold:2016 M2 Join Date: Dec 2014 Location: Tennessee iTrader: (0)	I am properly confused on this too and it's making my wheels spin. No pun intended. If I spin the wheel in neutral engine running, only one spins forward. The other side doesn't do anything. If I put it in drive with the engine running and spin one wheel, then the other side actually spins in the same direction.
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02-04-2023, 12:53 PM	#40
romoguy15 Enlisted Member 5 Rep 38 Posts Drives: 2020 X3 M Sport Sold:2016 M2 Join Date: Dec 2014 Location: Tennessee iTrader: (0)	I went and did the burn out test and every time I did it, I had two tire marks. Guessing I do have LSD?
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02-04-2023, 04:07 PM	#41
aerobod Car Geek 3615 Rep 3,585 Posts Drives: Caterham R500, M2-G87, Macan S Join Date: Mar 2008 Location: Calgary iTrader: (0)	You can get 2 tyre marks with a non-LSD diff due to the brake intervention when DSC or DTC is on or from the eLSD when they are off. Another way to check is to see what preload the diff has if it is a plate type LSD. With the transmission in neutral and left rear wheel touching the ground and blocked to stop it moving (parking brake off), the right wheel is removed to expose the axle nut. Put a socket on the axle nut and use a torque wrench to measure the breakaway torque by gradually increasing the torque if it is a click type wrench until the axle rotates, or looking at the torque value when the axle starts to rotate on a beam type wrench. The breakaway torque should be around 50Nm, but could be as high as 100Nm or so if it is the standard Drexler M-Diff LSD. Anything less than 30Nm would indicate no plate LSD or a need for a rebuild. Without this diff plate pre-load, even if you do have a plate type LSD fitted, it won't be very effective in stopping initial wheelspin.
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