Less diff lock for US variants?

[kyrix1st]

I have been a bad boy trying to get the tail out at junctions with my DCT(on OEM 75w-140) with only mild locks even with heavy left right flicks.

Strangely, the diff does not seem to lock as well as my 6MT(on Motul comp 75w-140)... is this a hardware or fluid difference?

[Redd]

Could be a worn diff?

[driftflo]

OE lsd needs difference in wheel speed (one wheel spinning like with an open diff) for a certain time to generate pressure on the clutches (resulting in lock... but with a big delay).

this is how the M variable diff works... (and the reason why it should be exchanged to a torque-sensing clutch type unit).

[kyrix1st]

Originally Posted by Redd

Could be a worn diff?

Unlikely... car has 14k miles on it. Previously driven by an old gentleman.

[Richbot]

Your 6MT was better, duh

But yeah, sounds normal. Could easily just be a peculiarity of how the alignment is, grippier surface, tires, car weight or whatever. If you're trying to flick it sideways on concrete vs. asphalt, for instance, it takes BIG inputs t to get it swinging.

[pbonsalb]

Turn the traction control off.

[kyrix1st]

Originally Posted by pbonsalb

Turn the traction control off.

This is of course with the traction control off.

[SAMM3Y]

Handbrake into it

[///Mobbin]

It's been posted that there's a good amount of "FM Booster" or "Friction-Modifier Booster" in the OE fluid which I believe was added by BMW at some point to reduce the differential noise some early owners were complaining about. Some folks have moved to Castrol Syntrax 75W140 which likely has less FM Booster in it, I tried it and didn't notice a ton of difference but didn't really do a back-to-back comparison either. See more info in these threads: LINK LINK2 LINK3 LINK4

Cool to have two cars to do a comparison with, maybe try the Castrol and see if you notice a difference?

I'm looking forward to picking up a real diff from driftflo one day, hopefully sooner than later!

[///Mobbin]

Another point to consider, the final drive ratio (and maybe gearing too) is different between DCT and 6MT, that may be more what you are feeling?

[pbonsalb]

Could be weather related. Traction is better in hot weather on good asphalt. Could also be tires. Old tires may have less traction than new ones. If you can’t make the car fishtail flooring it around a corner, I would be surprised.

[Richbot]

Originally Posted by ///Mobbin

Another point to consider, the final drive ratio (and maybe gearing too) is different between DCT and 6MT, that may be more what you are feeling?

I assume if it's at a "junction" he's doing this in 2nd gear, which has almost the exact same effective ratio 6MT to DCT, it only changes appreciably in 3rd and up where 3rd 4th and 5th are significantly shorter, 6th is a little shorter, and 7th is talelr than the 6MT 6th.

I think we need video. Lots of video, with accurate location and timestamp, so as to not provide it to the authorities

[Richbot]

Originally Posted by SAMM3Y

Handbrake into it

If you can't see your own tire marks out the windshield entering a corner, you've failed

[kyrix1st]

Originally Posted by Richbot

I assume if it's at a "junction" he's doing this in 2nd gear, which has almost the exact same effective ratio 6MT to DCT, it only changes appreciably in 3rd and up where 3rd 4th and 5th are significantly shorter, 6th is a little shorter, and 7th is talelr than the 6MT 6th.

I think we need video. Lots of video, with accurate location and timestamp, so as to not provide it to the authorities

Officer, I have been a bad man.

If I can figure out the right angle to shoot the difference before&after fluid change I will do. Of course, all done in Mexico.