E90 v. E46 M-differential

[trionalaw]

I searched this forum for the answer but probably missed it. Is there any difference between the two differentials other than the added power the E90 has to put up with?

When “ Googling ”it someone mentioned an electric differential for the newer series but I found nothing more about it. I doubt it is electric.

In any event, that is my question.

Happy Labor Day to everyone.

Jim

[Serious]

Originally Posted by trionalaw

I searched this forum for the answer but probably missed it. Is there any difference between the two differentials other than the added power the E90 has to put up with?

When “ Googling ”it someone mentioned an electric differential for the newer series but I found nothing more about it. I doubt it is electric.

In any event, that is my question.

Happy Labor Day to everyone.

Jim

IIRC they are exactly the same other then the final drive ratio.

Its not the electronic diff that the 135/335 gets.

[trionalaw]

Thanks so much for the reply. Isn't the electronic differential used on the I35 and 335 really part of the DSC/traction control system and not at all part of the differential? It just acts somewhat like a limited slip differential?

Jim

[southlight]

Originally Posted by trionalaw

Thanks so much for the reply. Isn't the electronic differential used on the I35 and 335 really part of the DSC/traction control system and not at all part of the differential? It just acts somewhat like a limited slip differential?

Jim

Yes, it's controlled via DSC and applies the brake when one rear wheel starts spinning.


Best regards,
south

[r53s65e90]

Originally Posted by seriousm3

Its not the electronic diff that the 135/335 gets.

Unfortunately the 335 does not have the e-diff. I believe only the 135 does. Both should have a real diff IMO.

[aus]

Originally Posted by r53s65e90

Unfortunately the 335 does not have the e-diff. I believe only the 135 does. Both should have a real diff IMO.

I'm sure it's just a re-program too.
The M series cars have a true LSD.

The X-drive has some fancy electronic clutch in the diff that will actually apply more power to the outside wheel while turning.

[mastek]

100% locking diff in the e9xm3's ... vs.... 60% (iirc) in the e46m3's

[Serious]

Originally Posted by mastek

100% locking diff in the e9xm3's ... vs.... 60% (iirc) in the e46m3's

They both use exactly the same shear pump LSD design... which has variable locking from 0-100%.

"The Variable M Differential Lock functions according to a simple principle: The difference in rotational speed that builds up between the two drive wheels whenever one of the drive wheels loses grip, either because it has become unloaded or hit a slippery surface, generates pressure spontaneously in an integrated shear pump. This pressure is then conveyed via a piston to a multiple-plate clutch, thereby channeling power to the wheel with better grip."

http://www.canadiandriver.com/2001/1...ntial-lock.htm

[ersin]

Originally Posted by mastek

100% locking diff in the e9xm3's ... vs.... 60% (iirc) in the e46m3's

The E46 M3 was also 100% locking!

From the "M3 Aftersales Training" document:

Fully variable M differential with locking action
This unique limited slip differential design is based on the E46 M3 and the E6x M5/M6 limited slip differential, where it is described in detail.

I believe the design is the same as the E46 M3 just more beefed up to hand the extra torque. It's a pretty slick design and it is not the electronic diffy that's in the 135.