Quote:
Originally Posted by YarkoDrives
Once your moving the vehicle uses a downshift rev match program:
front wheel speed sensors determine the vehicle speed, and throttle is cut to match RPMs.
I don't believe there is a gate sensor on the MT selector. The program assumes a downshift of 1 gear. based on braking?
You could try skipping from 4th to 2nd and see if you can get wheel slip.
-- The Shift program may just be a part of the intervention.
-- I got rid of my 135, and am running a 128 now.
Another option is to run slightly taller rears. then the program allows the rear wheels to be running a little faster (the same RPM on a larger circumference). With this configuration on my 128 I can lose the back end if I don't rev match. It should have a dramatic effect on the 135.
Also an advantage of the tall tire is it adds margin to the E-Diff slip limit, as the rear wheels are normally spinning at a slower RPM than the fronts, the program rarely can see rear slip.
I'm running 245/40/17 Front and 245/45/17 rear.
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You do quiet a bit of speculating here that I don't think is accurate.
E-diff's goal is to maintain a <5% wheel speed differential (Per Bosch documentation). If you run different aspect ratio ties in the rear all you will do is allow that wheel to spin at a maximum of 9.99% difference between the others wheels (granted the other 3 are all spinning at the same exact speed). I got that numbers by assuming your taller aspect tires are seen by the wheel speed sensors as spinning -4.99% slower than the front tires. This won't cause any intervention as is, but as soon as it starts to spin freely upon cornering the e-diff won't brake the wheel until it starts spinning 5% faster than the other wheels (-4.99 to +5% = 9.99% wheel speed difference).
Allowing the inside wheel to spin freely is not a good thing so not sure why you see this as a benefit. You won't be "losing the back end" in corners, you'll simply be spinning the inside tire more. Straight line acceleration is a mute point... E-diff will allow burnouts so long as both rears tires spin freely within 5% of each-other (Burnouts are hard to do since axel shafts are different lengths and more power always gets delivered to one wheel). Raising the ceiling to 10% differential, as seen above, will just allow you to smoke your tires for a bit longer. Once again, not exactly a benefit to spin tires in a timed event
E-diff is not a traction control system, so I don't see why the regulation you quoted would have any bearing on eliminating the e-diff with coding. I can tell you right now, disabling the e-diff without a mechanical LSD is not fun. You will be much slower as you will constantly be spinning the inside wheel and throwing up clouds of smoke lol.
The DSC system does indeed using steering angle as well as accelerator data to determine slip angle. Simply holding the traction control button down for 5seconds turns DSC functionality completely off leaving only e-diff on. Again, why would this be illegal? The 5 second hold turns off ALL assistance like corner braking control (on carslike the 1M), ASC, and DSC. I have no clue if disabling the accelerator will disable traction control entirely... I would think that you'll still get dynamic traction control intervention (ASC) since traction control doe snot make use of the yaw sensor... Then again, usually all systems go down when 1 sensor fails (the trifecta lights you describe seeing when you disconnected the yaw sensor)...
The other functions you quoted, like Rain disc drying, brake disc overheating, brake pre-tensioning, and brake fade compensation are all separate functions that are not effected by coding the e-diff off or by turning DSC off...
If you want to be able to run a bit of slip angle, then simply single click the traction control button... it won't allow you to swing the tail out as much as "track mode" on an M-series car, but you'll still be able to swing it out a bit while maintaining SOME level of traction control. personally, I always keep DSC 100% off...
Source:
Lots of documentation out there on how theses systems work:
DSC document:
https://bmw.spool
street.com/documents/e90-dynamic-driving-system-dsc-module.22/
Quick video: