Quote:
Originally Posted by feuer
All e90 have e-diff. Even entry level like 316i I have driven in Europe. Its part of the ABS which aplies brakes to the individual wheel or both wheels simultaneously. All newer BMW have it. When you start the car by default the e-diff will work in conjunction with the TC and DSC.When you turn of TC it will continue to work with DSC and allow some wheel spin. All e90 allow you to turn off DSC however the ABS can't be turn off. Now depending on build date but not necessarily when you turn off DSC some e-diff stay on and some turns off. Also depends whether is MT or AT. On a AT car e-diff will not turn off unless you are in Manual mode, at least that is what I have noticed. I have driven probably dozen different e90.
I've shared my cars info above but since you asked here it is again :
E90 335i MT M-tech built in March 2008 so pretty much last build for 2008 titled cars.
When I turn off DSC I can spin one or both wheels like endlessly. Non LSD
Correction -not endlessly because these cars do brake down a LOT.
I track and been out on the track during pouring rain so I can tell you that even at high speeds it will spin the whees. It will even red line. Also, since I live in Chicago and this is my DD I have covered a lot of miles on snowy and icy roads where the wheels do spin.
Aditionally, had plenty of fun at the harbors parking lot that is closed at winter doing power slides and donuts.
That is what I have found from driving and working on these cars.
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Ah, I think I see where the confusion lies now.
ABS (Anti-Lock Brake System) is not the e-diff, ADB (automated differential brake) is. ADB, as seen on 1 series vehicles and 3 series since march of 2008 is a discrete system from ABS (as well as DSC & DTC). It cannot be turned off without coding, not even in Manual mode.
To learn more about the e-diff, or eLSD, or ABD as it is variously called, this forum thread is a good place to start:
http://www.1addicts.com/forums/showthread.php?t=719012
The original post contains most of the valuable information that the rest of the thread mulls over.
This write up does a good job encapsulating exactly what the e-diff is:
http://www.bimmerfile.com/2010/11/15...rol-explained/
So, in conclusion, the ADB system is always active, however DSC and DTC can intrude and reduce its effect (cut throttle, apply brakes to realign the car or regain control, etc), but when all nannies are turned off with a 3 second press of the dtc/dsc button, it remains active and operates in the same manner as a mechanical limited slip differential, except it shifts torque via selective and progressive friction on the rear brakes (all brakes in a x-drive vehicle) rather than mechanical friction of gears in an LSD.