MDM wont turn off even if you want

[m4forum]

I would like to share my experience that could be helpful for drivers who want to really drive their M3/M4 on the track w/o any assistance (besides ABS).

Background : previously I owned two E46 M3 track cars modified which allowed me to progress from novice to instructor level on different clubs including for example Chin Motorsport. At some point I always drove them with the DSC off with exception of rain. With DSC off on E46 you always have control over the engine speed what gives the driver the ability to really drive the car and explore higher limits.

This year I decided to replace the E46 with an M4 and enjoy it as street/track car. They have very similar handling (predictable) but obviously the M4 has tone of power/torque what E46 lacks .... make it a very very fast street/track 4 seat car. But after few events and getting more familiar with it I noticed something was missing (gas pedal control).

Driving at NCM with the DSC off/inactive (keep pressing button until message shows on dashboard) noticed on turn 5 (high speed right sweeper) and turn 14 (high speed turn) even with my pedal on gas asking for more more speed I could not get it. As soon the wheel started to get straight noticed the power started to get delivered. Initially I thought missed pressing the switch correctly but after double checking on dashboard the DSC was really off. Found this extremely frustrating and wonder if somebody has similar experience.

I know for reading on this forum and own experience the system is very intrusive if keep it on but was expecting to be really turned off ... apparently this is not possible.

Reflection : if we consider the power level recent cars can delivery today and speeds they can achieve it isn't a bad idea to get some assistance on extreme situation I was just not expecting to notice it during "normal" driving condition at the track.

For information my car already has EURO MDM flashing as well steering and diff.

Your comments are appreciated.

[FormulaMMM]

Are you pressing and holding, or repeatedly pressing as you indicate? You have to press and hold it down for a few seconds to turn off.

If you are pressing and holding until DSC is off, maybe something went awry with your coding. Off still means fully off in F8X gen.

You can also program DSC off with your M buttons.

[SYT_Shadow]

Originally Posted by FormulaMMM

Off still means fully off in F8X gen.

You can also program DSC off with your M buttons.

Exactly. Off means off. This isn't Mercedes we're talking about!!

[Pic18]

Not to second guess you did the procedure correctly, but just pressing MDM once gives you a light on the dash that traction (or DSC I cant remember) is off and it makes you acknowledge a second time on the screen although TC/DSC are not completely disabled. You need to hold down the traction button a second time for several seconds to completely disable.

[calubi]

I've experienced similar issues on track, where light throttle around turns would cause an intermittent power cut, complete with exhaust burps. Like if you were to alternate stabbing and releasing the throttle. This is with DSC fully off (programmed in M mode, two presses to confirm).

What ended up helping a lot was turning the engine mode down to Sport instead of Sport+. I think I was hovering right on the edge between no throttle and light throttle with the Sport+ throttle mapping, so tiny changes in pedal position were causing the car to think I was lifting. With the Sport throttle mapping, I have more range at the beginning of throttle pedal travel to fine tune light throttle. Or at least that's my current theory.

I have Euro MDM, but MDM should be off anyway unless I'm missing a step...

[Gomeler]

I've gone even further, at the recommendation of some people on this forum, and run the engine in efficient. Great throttle modulation, especially under cornering. Downside is the exhaust valves muffle the exhaust a good bit at lower RPM, turns out I was kind of using that as an audible cue at times. Took ~2 hours on-track but I'm faster now in efficient than when I was in sport.

Sport and sport+ felt fast initially when I was just pointing and shooting the car, but the limits of those throttle maps revealed themselves when I start asking more of the tires in corners.

I have dsc off + efficient tied to M2, and I have zero issues looping the car from getting onto the throttle too soon and too aggressively.

[m4forum]

tks for the reply. I am pressing and holding until the message DSC inactive shows up. My system is in theory off. I am driving on sport mode as find sport+ too aggressive to modulate. never tried in efficient mode.
so you guys are saying with DSC off regardless of other conditions (wheel spin, steering angle, ... ) you can fully control engine speed?

[FormulaMMM]

Originally Posted by m4forum

tks for the reply. I am pressing and holding until the message DSC inactive shows up. My system is in theory off. I am driving on sport mode as find sport+ too aggressive to modulate. never tried in efficient mode.
so you guys are saying with DSC off regardless of other conditions (wheel spin, steering angle, ... ) you can fully control engine speed?

I've not experienced any conditions in which you don't have full throttle control, or where power is cut with a loss of traction. I've kept my foot in it with the back end out and in combination with substantial steering correction. During snap oversteer moments, for example, where every traction system I know of short of Chevy Race (maybe) would have intervened.

DSC off you're definitely on your own.

[SYT_Shadow]

Originally Posted by Gomeler

I've gone even further, at the recommendation of some people on this forum, and run the engine in efficient. Great throttle modulation, especially under cornering. Downside is the exhaust valves muffle the exhaust a good bit at lower RPM, turns out I was kind of using that as an audible cue at times. Took ~2 hours on-track but I'm faster now in efficient than when I was in sport.

Sport and sport+ felt fast initially when I was just pointing and shooting the car, but the limits of those throttle maps revealed themselves when I start asking more of the tires in corners.

I have dsc off + efficient tied to M2, and I have zero issues looping the car from getting onto the throttle too soon and too aggressively.

Glad it's working for you. It sounds so counterintuitive but it's true.

I also lament the lack of sound when running efficient :'(

[Bon F80]

Originally Posted by m4forum

tks for the reply. I am pressing and holding until the message DSC inactive shows up. My system is in theory off. I am driving on sport mode as find sport+ too aggressive to modulate. never tried in efficient mode.
so you guys are saying with DSC off regardless of other conditions (wheel spin, steering angle, ... ) you can fully control engine speed?

yes, "off" is fully off, the engine would pick up rpm without any hesitation.

the situation you described sounds more like when MDM is on. seems like there is some programming issue. have u ever tried comparing the behaviours between your car's MDM and your car's "off"?