Quote:
Originally Posted by PrematureApex
You can't shut the E-diff full off via the TC button like you can in all the other cars?
And I'm just about 90% sure you can shut it off via coding.
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The e-diff unfortunately does not get shut off with full DSC and DTC off (it doesn't on the 335i and 135i either). I always run with full DSC and DTC off and it doesn't matter as far as the e-diff goes. I have been researching this for a while, spurred on by mysterious power loss on the track. I scanned the DSC module for codes and found one that says, "reduced power output due to brake disc temp too high." It is important to note that there are no actual brake disc temp sensors; this is a calculated value based on speed and brake application (I found this in a BMW technical document).
What is basically happening is that the e-diff (controlled by the DSC module) isn't aware that you have upgraded brakes and pads. When you drive on the track and have some slip angle, the computer continually corner brakes (the e-diff doing its job). This does two things - prematurely wears your inside brake pad and rotor, and slows down the car. The ECU sees the constant corner braking happening and assumes you are overheating the pads, and cuts power.
I have read in several places that you can indeed code off the e-diff (apparently certainly extremely early 335s didn't come with it enabled) but have found nowhere that shows how to do it. One guy claims he knows how but won't share due to "liability issues."
I will pay $100 if someone can show me how, it is costing me that more than that in brake pad wear each event. I know how to code and have a computer set up for it, just can't figure out how to code out the e-diff. Have asked a few other people including Alex at Alpine and nobody seems to know.