Quote:
Originally Posted by Mirko
I stumbled across a write up of DTC for our MK60 module.
Page 17/24
https://dl.dropboxusercontent.com/u/...20Dynamics.pdf
"DTC achieves maximum possible traction essentially by expanded ASC and DSC control thresholds. Compared to the ASC/DSC function, DTC mode allows a little more "drift" at low speeds and transverse acceleration (increased rear wheel spin is permissible up to a speed of approx. 45 mph). This allows the engine power output to remain without an extreme reduction of power, improving propulsion.
On approaching higher speeds and transverse acceleration (measured by the yaw rate sensor), the DTC function acts more and more like the "normal" ASC and DSC function and the slip thresholds are reduced back to a conservative mode for stability reasons." |
Well, I guess the DTC mode wasn't some big "secret" hidden away from the E85/86 owners. It is very odd it was not activated from the factory!
I finally had an opportunity to get my MR out of storage and play with the DTC function, just on street roads. The test was a rolling 90° corner in second gear with early aggressive acceleration out of the corner. Note: I still had my Fun-flats on and the temp outside was in the low 40's F
First, with full traction control on, as expected, power is cut and the car is stabilized very quickly.
Next, with the DTC function on, a slight step-out of the rear and spinning wheels, it didn't really
feel like there was much intervention. With a slight steering correction and slight reduction in accelerator, the car squared up nicely and continued on down the road in an aggressive manor.
Last, I turned off everything, same corner.
HOLY CRAP! 
I almost lost control of the vehicle! I was all over the road, into the oncoming lane. However, as others have said, a quick steering correction and a reduction of gas pedal and the car quickly centers itself. Perhaps I was a bit more aggressive with the final test, I'm not sure. But, it certainly showed me the DTC mode, although it
feels like it is not intervening much, I suspect it is still doing quite a bit (which is a GOOD thing AFAIC)
Being new to the Z4M, I'm really looking forward to putting on my extreme summer tires and getting her out to some AutoX events so I can learn more about the handling characteristics at the limits. Like others have said, it seems like she can be a real handful with too aggressive of inputs.