[166m]

I've got a 440i X drive 6 speed and I don't want to keep the open diff on it. Is there any reason limited slip diffs aren't compatible with the X drive system, and do you need the M performance diff or can you pull one off an m3/4?
Cheers!

[im_an_alien]

F3x series LSD is clutch type, while f8x LSD is electronic. The M car diffs won't bolt on to the f series chassis, not to mention driveshaft/axle shaft compatibility. There is an LSD for x drive F30 IIRC
Edit: looks like LSD for x drive will require modification or going aftermarket.

[isenc2]

See Farkle's LSD review on his wagon, it will explain everything. If you desire to do a LSD swap, please see my review of wavetrac lsd with my 340i xDrive. Short answer, no, BMW never made a LSD compatible with F30 LCI xdrive cars, 6MT or ZF8. If you want m3/m4 diff, you need to swap to F8X rear subframe and axle, there's a post about it on B58 group on FB.

[johnung]

Originally Posted by 166m

I've got a 440i X drive 6 speed and I don't want to keep the open diff on it. Is there any reason limited slip diffs aren't compatible with the X drive system, and do you need the M performance diff or can you pull one off an m3/4?
Cheers!

You’ve already got great advice in the comments. 10+ years ago BMW designed the aftermarket M Performance LSDs with RWD in mind simply because RWD was prevalent on the track and XDrives weren’t typical weekend trackers. You can actually see it in how the original LSD Marketing materials were written that the assumption was that only RWD owners would be interested. I mean it did cost about $3k installed.

I was lucky that my 335i XDrive automatic had the same final drive ratio and the MP LSD meant for the 335i RWD model just bolted right in. (Manual or Automatic determines the final drive ratio used.)

However as someone already mentioned, BMW made some changes with the LCI model 340ix/440ix so the MP LSD doesn’t just bolt in. I believe there may be posts that discuss which parts need to be swapped for it to fit/work.

Quiafe LSD may be worth looking into. VAC Motorsports in Philadelphia has them.

Please post what you came up with. Good luck!