Enabled DTC mode on the ///M (Track mode ?)

[pungo]

On my 2007 Z4MC, I coded the MK60 module to enable the DTC light to come on. Now, with a quick press of the DSC button, the DTC light comes on in the instrument cluster. When the DSC button is held down for a few seconds, the DSC off symbol lights up. Now my car has 3 modes like the non-M cars have.

I haven't had allot of time to experiment with it, but when in DTC mode, it does allow for much more wheel spin and more sideways action before the nannies kick in when compared without the DTC mode enabled. I need to find some open space to get familiar with the limits. I believe this is like the "M3 track mode". The M3 also uses the MK60 module. The DTC mode feels somewhere in between DSC on and DSC off.

[bignosejim]

Great job, a lot of people will be interested in this!! What did you have to change to make this happen? Did you just change the model variant to roadster?

You gotta let us know!!

[pungo]

The only change I made was to change the value of TDR from nicht_aktiv to activ. Give it a try and report your results.

I believe TDR stands for "TRAKTION DIFFERENZ REGELUNG" which google translated to "TRACTION DIFFERENTIAL SYSTEM".

BMW defines DTC as:
Dynamic Traction Control (DTC) is a sub-function of the Dynamic Stability Control (DSC) system that can be turned on and off. DTC has two major roles: to regulate traction and to enable sports-style driving while providing active stability control.

The DTC also makes driving on snow and ice-free roads more dynamic. When activated, the DTC allows sporty drivers more room to manoeuvre around curves than the Dynamic Stability Control and even permits controlled drifts. The driver retains complete control over the vehicle in every situation and the Dynamic Stability Control’s stabilising measures remain active even when the DTC is activated.

There are some other parameters than may reduce the DSC intervention but I didn't change any of them.

Here's a few of interest:
UEBERSTEUERN_MUE_0_2 - OVERSTEER FRICTION COEFFICIENT 0 2 [DATA<128 ? COEFFICIENT=1.5+(DATA/128) : COEFFICIENT=1.5+((DATA-256)/128)]

UEBERSTEUERN_MUE_1_2 - OVERSTEER FRICTION COEFFICIENT 1 2 [DATA<128 ? COEFFICIENT=2.5+(DATA/64) : COEFFICIENT=2.5+((DATA-256)/64)]

UNTERSTEUERN_MUE_1_2 - UNDERSTEER FRICTION COEFFICIENT 1 2 [DATA<128 ? COEFFICIENT=2.5+(DATA/64) : COEFFICIENT=2.5+((DATA-256)/64)]

UNTERSTEUERSCHWELLE_2 - UNDERSTEER THRESHOLD 2 [DATA<128 ? COEFFICIENT=2.5+(DATA/64) : COEFFICIENT=2.5+((DATA-256)/64)]

GEARMOMENTREGLER_MAX_HA_2 - GEAR-TORQUE CONTROL MAXIMUM REAR AXLE [DATA<8 ? PERCENTAGE_%=(DATA*4000)/1024 : PERCENTAGE_%=((DATA-16)*4000)/1024]

GEARMOMENTREGLER_MIN_HA_2 - GEAR-TORQUE CONTROL MINIMUM REAR AXLE [DATA<8 ? PERCENTAGE_%=(DATA*4000)/1024 : PERCENTAGE_%=((DATA-16)*4000)/1024]

[bignosejim]

You've definitely been working on more than just headlights lately. Good info above. I'll be able to get that coded later this week or by the weekend.

[mtrhed]

Nice work!

I'm going to have to give this a try.

[RossBMWZseries]

So when DSC is deactivated, we can burn/peel out, fishtail and have fun. How does DTC compare to that? And why would we need it when it's not even an option on the ///M? I'm not connecting the dots

[Vanne]

nice work mate, but "TRAKTION DIFFERENZ REGELUNG" which google translated to "TRACTION DIFFERENTIAL SYSTEM", is incorrect.

regelung is control.

either way, i guess it has a similar meaning in this application. and i am not sure about difderenz either, i think that may actually difference, not differential.

either way, bloody good job mate looking forwards to the results on this for the track i don't like the nanny, but bloody hell its full on otherwise

[pokeybritches]

If this truly works, it will be one of the best mods ever discovered.

[The HACK]

I wonder if it's simply a "legacy" program left in the control modules. On "later" BMWs, like the E9X, DTC has a programming mode to "simulate" a limited slip differential by braking individual rear wheels that's slipping to send power to the wheel that's NOT slipping to promote traction. And instead of completely re-writing the code for M cars that came with an LSD, the same codes were left in the system but coded out not to be accessible, since the DTC coding and functionality is useless with a mechanical LSD.

[pungo]

Originally Posted by The HACK

I wonder if it's simply a "legacy" program left in the control modules. On "later" BMWs, like the E9X, DTC has a programming mode to "simulate" a limited slip differential by braking individual rear wheels that's slipping to send power to the wheel that's NOT slipping to promote traction. And instead of completely re-writing the code for M cars that came with an LSD, the same codes were left in the system but coded out not to be accessible, since the DTC coding and functionality is useless with a mechanical LSD.

I was experimenting with the DTC mode enabled today. I acceleration hard from a roll and both wheels started spinning and with lots of fishtailing. The traction control never engaged. With DTC engaged, there's much less DCS going on. Try it for yourself and post your results.

The MK60 module is also used on the M3 which there is a mode called "M track mode" as explained below:

M Track mode:
M track mode is a feature of the Dynamic Stability Control DSC, designed for driving on dry roads. It allows you to drive with higher longitudinal and lateral acceleration, whereas driving stability is somewhat reduced. Only in its absolute limit will the system try to stabilize the vehicle by reducing engine power and applying brakes to the wheels. Under these driving conditions the driver must be prepared to perform corrective steering movements if necessary.

By default, M Track mode is off after each engine start.

Warning: While M Track mode is active, stabilizing interventions are performed to a reduced extent only.

Note: To maintain vehicle stability, always drive with DSC switched on and M Track mode switched off whenever possible.

[The HACK]

If both wheels are spinning, neither the mechanical LSD nor the brake simulating eLSD as a function of DTC would engage. Even with the old school, pre-DTC E46, you CAN spin both wheels when traction levels are nearly equal (dry pavement).

Problem is, how do we figure out, if it indeed is pulling the DTC programming to brake the individual wheels, if the car's electronics thinks faster than the LSD's mechanical intervening? Would the DTC mode simply be the same exact thing as DSC off since the brakes wouldn't sense individual wheels slipping (the mechanical LSD would prevent that)?

I suppose, the next test is to see if you can find a patch of road with two different traction levels (half wet, the other half dry) and see how the DTC mode reacts. If it's braking individual wheels, we'll now that it's doing SOMETHING. If not, the next step is to determine if the DTC mode is different from DSC off on track.

[inTgr8r]

This is VERY interesting!

I would want to be sure that it is in fact like M track mode; that it still has a reduced level of control.

[RossBMWZseries]

This IS really interesting. Quite honestly I always drive with DSC enabled. I only remove it when going on a straight...fast

[jdoublehcubed]

This is nice option for turning down the traction control but avoiding a crisis if you find a surprise puddle on a curve, for example.

Great find!

[bignosejim]

I just enabled mine today. You can still get the dsc to intervene when going around a corner from a stop. I didn't have too much time to experiment with it today. It's nice to have a third option to dsc on/off. From the research I've done, it appears this is similar to what the non-M Z's have (and similiar to M track mode). I think that any e-lsd option available on 3 series isn't available for Z series cars. They use a slightly different module. The non-M Z's do have a similar function but that would have to be changed on purpose for M cars. I think that it will still correct excessive spin by braking individual wheels.

[inTgr8r]

This sounds promising

[mfanatic325]

I just drive with DSC fully off; always

not making light of your work or anything hehe, just playing around. Although it's true that I do drive with DSC off 99% of the time, I can see the merit in having in-between modes.

[The HACK]

Originally Posted by bignosejim

I just enabled mine today. You can still get the dsc to intervene when going around a corner from a stop.

Based on this description, and the rest of the thread...

I'm going to say this is exactly what I suspect. The programming for DTC is left in the DSC module because BMW didn't want to customize a module just for our cars.

The fact that you can spin the tires in a straight line, where both tires are losing traction, on dry pavement with this setting enabled, and still engage DSC in a turn, means you're defeating the purpose of the mechanical LSD. The programming is left there for cars with open diffs as to interfere by braking individual wheels in the rear (by the way, said feature was available as early as 2003 when the Z4 was first introduced), but when BOTH wheels are spinning the rear brakes won't kick in because, to the system, traction levels are equal for both sides.

M-Track mode on the E46 actually is a different threshold programmed in to DSC, where on a straight-line it'll give you some leeway to spin the tires, but will eventually reign you in because a moderate amount of tire spin is good for launch (put heat into the rear tires). It also dials back DSC in the corners allow for a greater degree of slip angle before intervening.

If what y'all are saying is true, that DSC still intervenes while turning, then you're in essence using the rear brakes to simulate what a LSD would do, when the car already has a mechanical LSD to start with...And a very fancy one at that.

The quickest way to test it, is to drive around spiritedly in an empty parking lot with DSC off, then drive with the "DTC" mode on, then measure the rear rotor temp to see if it's activating the rear brakes more. If it is, then turning on this "mode" is a big mistake.

I don't have a beef in this, by the way. Now, if you can find a way to program it to default to DSC OFF when starting the car, I'll be all ears.

[StickMon]

^WHS.
Cool thing to find out and play with, but probably redundant with, and not as good as, the LSD, which is why it's disabled on the ///M.

Now, if you can find a way to program it to default to SPORT mode when starting the car, I'll be all ears.

[Frank851]

What software/ cables are you using to make the changes to the code? I would like to try this and some other code changes. Thanks for any info you can provide.

[asirvr4]

Originally Posted by The HACK

Based on this description, and the rest of the thread...

I'm going to say this is exactly what I suspect. The programming for DTC is left in the DSC module because BMW didn't want to customize a module just for our cars.

The fact that you can spin the tires in a straight line, where both tires are losing traction, on dry pavement with this setting enabled, and still engage DSC in a turn, means you're defeating the purpose of the mechanical LSD. The programming is left there for cars with open diffs as to interfere by braking individual wheels in the rear (by the way, said feature was available as early as 2003 when the Z4 was first introduced), but when BOTH wheels are spinning the rear brakes won't kick in because, to the system, traction levels are equal for both sides.

M-Track mode on the E46 actually is a different threshold programmed in to DSC, where on a straight-line it'll give you some leeway to spin the tires, but will eventually reign you in because a moderate amount of tire spin is good for launch (put heat into the rear tires). It also dials back DSC in the corners allow for a greater degree of slip angle before intervening.

If what y'all are saying is true, that DSC still intervenes while turning, then you're in essence using the rear brakes to simulate what a LSD would do, when the car already has a mechanical LSD to start with...And a very fancy one at that.

The quickest way to test it, is to drive around spiritedly in an empty parking lot with DSC off, then drive with the "DTC" mode on, then measure the rear rotor temp to see if it's activating the rear brakes more. If it is, then turning on this "mode" is a big mistake.

I don't have a beef in this, by the way. Now, if you can find a way to program it to default to DSC OFF when starting the car, I'll be all ears.

Clever idea to test, but brakes might cool off to fast.

Why it is a mistake??

[StickMon]

Originally Posted by Frank851

What software/ cables are you using to make the changes to the code? I would like to try this and some other code changes. Thanks for any info you can provide.

This was done with NCS Expert.
Try searching for "NCS Expert" "GT1" "Progman" "DIS".
It's a big topic.