[oopy]

Update: Spoke to the BMW spare parts department enquiring about the diff supplied on my car (7603759-04) and their parts catalog states this is a limited-slip diff, the part number that should have been supplied on my car was 7603760 (open diff).

This surprises me and I'm still skeptical but until I've got a better way to confirm, the part numbers are usually the best way to tell. They also mentioned that a bunch of Aus-delivered m140i's and m240i's had LSD's spec'd in the build configurations linked to the VIN's but upon visual confirmation of the part numbers on the supplied diffs - these ended up being open. As a FYI and out of curiosity the cost to supply the open diff as a spare part was more expensive than the M perf LSD - pricing of parts aren't always determined at face-value.

[JMcLellan]

Originally Posted by oopy

Thanks for confirming, did you by any chance get the part number for your specific diff?

Do you mean the part number for the diff that came with my car, or the LSD I had installed?

[oopy]

Originally Posted by JMcLellan

Do you mean the part number for the diff that came with my car, or the LSD I had installed?

The original one that came with your car

[XutvJet]

Originally Posted by oopy

Update: Spoke to the BMW spare parts department enquiring about the diff supplied on my car (7603759-04) and their parts catalog states this is a limited-slip diff, the part number that should have been supplied on my car was 7603760 (open diff).

This surprises me and I'm still skeptical but until I've got a better way to confirm, the part numbers are usually the best way to tell. They also mentioned that a bunch of Aus-delivered m140i's and m240i's had LSD's spec'd in the build configurations linked to the VIN's but upon visual confirmation of the part numbers on the supplied diffs - these ended up being open. As a FYI and out of curiosity the cost to supply the open diff as a spare part was more expensive than the M perf LSD - pricing of parts aren't always determined at face-value.

Did you buy your car used or new?

[XutvJet]

The biggest apparent differences in these cars with an LSD vs open diff are the following behaviors and is based on my experience running an open diff for about 2 years and then installing the MP LSD and running that for nearly 6 years:

1) In Sport+, Traction, or DSC Off, when coming through a sweeper and the back starts the break loose, with the LSD, you can power through it and keep momentum and accelerate. With the open diff, the back end swings wide, momentum is lost, and you cannot accelerate until the slip is managed by the traction control and the "electronic LSD" (eLSD; only operational in DSC Off). Basically with the LSD, you power through a sweeper and steer with the rear axle with the throttle.

2) With the LSD, the car launches FAR harder. I can launch my M235 6MT on 245 width tires at around 3500rpms with a bit of clutch slip. With an onboard recorder, the car is consistently 0.25 (on average) seconds quicker to 60. That is very significant. With the open diff, there was way more wheel spin and launching the car way more inconsistent and difficult. With the LSD, it is like adding 500lbs over the rear axle.

[JMcLellan]

Originally Posted by oopy

Update: Spoke to the BMW spare parts department enquiring about the diff supplied on my car (7603759-04) and their parts catalog states this is a limited-slip diff, the part number that should have been supplied on my car was 7603760 (open diff).

This surprises me and I'm still skeptical but until I've got a better way to confirm, the part numbers are usually the best way to tell. They also mentioned that a bunch of Aus-delivered m140i's and m240i's had LSD's spec'd in the build configurations linked to the VIN's but upon visual confirmation of the part numbers on the supplied diffs - these ended up being open. As a FYI and out of curiosity the cost to supply the open diff as a spare part was more expensive than the M perf LSD - pricing of parts aren't always determined at face-value.

Here you go. This is a pic of the sticker on the top of my stock diff. According to what you are saying above that would mean I removed an LSD from my car to put a new LSD in. Maybe the parts dept meant the E-LSD? My car behaves so much differently with the LSD so I'm assured there was an open diff/E-LSD on my car when I bought it. If for some reason I'm wrong and spent $3k for no reason then the silver lining is that I have a 30K miles LSD for sale then

[Jcoop901]

Anyone have it listed on their window sticker?

[dradernh]

Originally Posted by Jcoop901

Anyone have it listed on their window sticker?

The fellow that ordered my car went the other way, so I went with a Wavetrac.

[oopy]

Originally Posted by XutvJet

Did you buy your car used or new?

Was demo stock from the dealership (dealer/HQ ordered vehicle)

So tried again with the wheel spin test but got no where....
Even with the transmission warmed up both wheels spin when lifted in the air with the car on and transmission in neutral.

I tried lowering the car just enough to apply load to both sides to stop them moving by themselves and then proceeded to turn one wheel and the other followed in the same direction.

I also strangely managed to turn the car off whilst still in neutral and this was the weirdest behaviour, turning one wheel and the other side did not move!

So nothing conclusive unfortunately....

[oopy]

Originally Posted by JMcLellan

Here you go. This is a pic of the sticker on the top of my stock diff. According to what you are saying above that would mean I removed an LSD from my car to put a new LSD in. Maybe the parts dept meant the E-LSD? My car behaves so much differently with the LSD so I'm assured there was an open diff/E-LSD on my car when I bought it. If for some reason I'm wrong and spent $3k for no reason then the silver lining is that I have a 30K miles LSD for sale then

Thanks for that, I'm still skeptical that the dealership parts dept was correct with this but keen to debunk/confirm it.

[oopy]

Originally Posted by XutvJet

The biggest apparent differences in these cars with an LSD vs open diff are the following behaviors and is based on my experience running an open diff for about 2 years and then installing the MP LSD and running that for nearly 6 years:

1) In Sport+, Traction, or DSC Off, when coming through a sweeper and the back starts the break loose, with the LSD, you can power through it and keep momentum and accelerate. With the open diff, the back end swings wide, momentum is lost, and you cannot accelerate until the slip is managed by the traction control and the "electronic LSD" (eLSD; only operational in DSC Off). Basically with the LSD, you power through a sweeper and steer with the rear axle with the throttle.

2) With the LSD, the car launches FAR harder. I can launch my M235 6MT on 245 width tires at around 3500rpms with a bit of clutch slip. With an onboard recorder, the car is consistently 0.25 (on average) seconds quicker to 60. That is very significant. With the open diff, there was way more wheel spin and launching the car way more inconsistent and difficult. With the LSD, it is like adding 500lbs over the rear axle.

I'm running 265 cup 2's on the rear and when at temp with moderate to aggressive throttle inputs it does not light up either side - I'd have to be really reckless with the throttle to light them out of a corner. (MHD St2+, B58tu HPFP, Wagner downpipe, MPPSK exhaust)

[Rocky58]

I don't know if this adds to the discussion but BMW and others list 33107603760 as having the old part number 33107603759. (59 superseded by 60)
So not a catalog omission. That catalog part 33107603759 has been "discontinued" and replaced by 33107603760. Both with 2.81 ratios for auto m240i

https://parts.bmwmonterey.com/p/Bmw_...107603760.html

On this website, you have to go down and click to see the old part numbers:
Old product numbers
33-10-7-603-759
33107603759
33 10 7 603 759
https://www.schmiedmann.com/en/produ...product=R17592