DSC ON vs MDM vs DSC OFF

[AO08BAS]

This might be a really dumb question so please bare with me. But I've seen a lot of threads talking about "Drive with traction control fully off to feel the full power of the car" etc or that you don't know what the car can do unless you have the nanny control totally off.

Now please can someone clarify as I thought the DSC only kicks in when the car loses power and it cuts the power? If that is the case then aside from when you lose traction you still would have the exact same amount of power right?

I guess what I am trying to ask is with the driver assists on does the car actually have less power going the wheels by default? Or does it only kick in once you lose traction at which case it cuts the power.

[SMGCFP]

My understanding is that if the tires lose grip, the car will cut power. So theoretically you have all use of the power. However, the theory (or reality) is that you will not get all the power the car has unless the wheels are permitted to slip (more than MDM allows). No one says you'll go faster (necessarily), but the car will put out more power, even if that power ends up as rubber on the pavement.

Granted a professional or even very good driver can turn a faster lap with the DSC off as opposed to MDM or on. This is because the car's computer doesn't allow you get to the complete ragged edge (Days of Thunder term). A good driver can push the car to the absolute physical limit without losing traction (traction loss =slower lap time). DSC or MDM doesn't give you that opportunity as it intervenes quite a bit earlier than "the limit".

Hope this helps.

[mkoesel]

Originally Posted by ZeCP

I guess what I am trying to ask is with the driver assists on does the car actually have less power going the wheels by default?

No.

Or does it only kick in once you lose traction at which case it cuts the power.

The stability control system uses various sensors to determine what to do - cut engine power, apply the brakes, send more power to one wheel or the other using the differential (I believe), and probably some other things as well. It has both reactive and proactive algorithms, so it will not only intervene when it detects the car is not currently in a stable state, but it will also actively try to keep that situation from occurring when the car is nearing the limits of traction and/or appears to be about to spin (or perhaps tip, etc.).

Therefore, as SMGCFP relates above, in order to keep the system from interfering when you are driving on the "complete ragged edge" (great term, BTW), you must turn it completely off. As he also mentions, it is advised that you possess a certain level of skill before attempting extreme driving maneuvers. However, given the high torque of the S55 engine, the reality is that the traction control component of the system can be very intrusive to the point that an "innocent" attempt to achieve maximum acceleration from a stop-light, for example, can be thwarted with DSC ON. This is why you see so many people talk about driving with it OFF. Unfortunately, even the MDM mode can be too intrusive in some situations.

[SMGCFP]

Originally Posted by mkoesel

Therefore, as SMGCFP relates above, in order to keep the system from interfering when you are driving on the "complete ragged edge" (great term, BTW), you must turn it completely off. As he also mentions, it is advised that you possess a certain level of skill before attempting extreme driving maneuvers.

For the record, I have not turned mine off because I do not possess this type of skill. Someone the other day was talking about their 1986 or 1996 Porsche and commenting that it had more "usable horsepower/torque". This car has lots of "unusable" hp/torque for a novice/average driver like me.

Seriously, buy Gran Turismo for PS4 and drive the M4 with the DSC off. I can't control the car consistently. I know it's not exactly the same, but I did one of those hot laps with the instructor at an M track day and instead of watching the track I watched the driver. Their hands and feet are so quick, and it has to be reflex. There's no time to think.

Driving like that is too hard. I'll stick to my day job.

[ntg44]

Originally Posted by SMGCFP

For the record, I have not turned mine off because I do not possess this type of skill. Someone the other day was talking about their 1986 or 1996 Porsche and commenting that it had more "usable horsepower/torque". This car has lots of "unusable" hp/torque for a novice/average driver like me.

Seriously, buy Gran Turismo for PS4 and drive the M4 with the DSC off. I can't control the car consistently. I know it's not exactly the same, but I did one of those hot laps with the instructor at an M track day and instead of watching the track I watched the driver. Their hands and feet are so quick, and it has to be reflex. There's no time to think.

Driving like that is too hard. I'll stick to my day job.

I still feel that I should have needed to pass a higher level driver's license exam to buy this car. 450hp is way too attainable nowadays. I don't think current driver's license exams/laws were written with this level of power in mind to the every day driver.

[Zoli007]

The main issue with setting a fastest lap time is that to get the last few tenths, the car needs some slip angle. MDM will allow a little bit but it is still intrusive. When we did the driving events for the BMW Ultimate Driver, we had to keep MDM on. While not horrible, it definitely kicked on in areas I thought it was not needed and was holding me back from setting times. But everyone had it so we had to adapt.

But definitely don't want to be playing without knowledge of car control or this car particularly. An empty wet parking lot is an excellent place to learn.

[NYG]

Originally Posted by ZeCP

This might be a really dumb question so please bare with me. But I've seen a lot of threads talking about "Drive with traction control fully off to feel the full power of the car" etc or that you don't know what the car can do unless you have the nanny control totally off.

Now please can someone clarify as I thought the DSC only kicks in when the car loses power and it cuts the power? If that is the case then aside from when you lose traction you still would have the exact same amount of power right?

I guess what I am trying to ask is with the driver assists on does the car actually have less power going the wheels by default? Or does it only kick in once you lose traction at which case it cuts the power.

The car doesn't have less power going to the wheels, it just begins to cut the power as soon as it senses changes in traction on any tire. Given that you're in a very torquey / rear happy car, it will be heavily involved in all of your driving. MDM gives you a little bit of permission to slip the tires but it's still INSANELY intrusive. DSC off depends entirely on you, so if you screw up, nothing will really save you.

Test it out on a nice weather day with some spirited street driving, nothing crazy. You'll even notice from a stop light that MDM and DSC intervenes with your driving regularly when compared to DSC off.

[Sedan_Clan]

Originally Posted by SMGCFP

For the record, I have not turned mine off because I do not possess this type of skill. Someone the other day was talking about their 1986 or 1996 Porsche and commenting that it had more "usable horsepower/torque". This car has lots of "unusable" hp/torque for a novice/average driver like me.

Seriously, buy Gran Turismo for PS4 and drive the M4 with the DSC off. I can't control the car consistently. I know it's not exactly the same, but I did one of those hot laps with the instructor at an M track day and instead of watching the track I watched the driver. Their hands and feet are so quick, and it has to be reflex. There's no time to think.

Driving like that is too hard. I'll stick to my day job.

You're overthinking driving. Sure, it can be overwhelming at first (...just like anything else that requires skill.....racing bikes, extreme snowboarding, tactical shooting, etc.), but time and practice will get you there.

[CanAutM3]

Originally Posted by mkoesel

No.



The stability control system uses various sensors to determine what to do - cut engine power, apply the brakes, send more power to one wheel or the other using the differential (I believe), and probably some other things as well. It has both reactive and proactive algorithms, so it will not only intervene when it detects the car is not currently in a stable state, but it will also actively try to keep that situation from occurring when the car is nearing the limits of traction and/or appears to be about to spin (or perhaps tip, etc.).

Therefore, as SMGCFP relates above, in order to keep the system from interfering when you are driving on the "complete ragged edge" (great term, BTW), you must turn it completely off. As he also mentions, it is advised that you possess a certain level of skill before attempting extreme driving maneuvers. However, given the high torque of the S55 engine, the reality is that the traction control component of the system can be very intrusive to the point that an "innocent" attempt to achieve maximum acceleration from a stop-light, for example, can be thwarted with DSC ON. This is why you see so many people talk about driving with it OFF. Unfortunately, even the MDM mode can be too intrusive in some situations.

^ All this. Very well said!

[SMGCFP]

Originally Posted by ntgarage44

I still feel that I should have needed to pass a higher level driver's license exam to buy this car. 450hp is way too attainable nowadays. I don't think current driver's license exams/laws were written with this level of power in mind to the every day driver.

The most impressive thing to me on this car is how great the brakes are. You can have a lot of fun hitting an exit ramp at 80/85mph and hitting the brakes right before the curve, and the car just goes from 85 to 40 in what feels like 100 ft.

The handling is the most fun part of the car, not the power. At least to me.

[55parallelM3]

Originally Posted by SMGCFP

For the record, I have not turned mine off because I do not possess this type of skill. Someone the other day was talking about their 1986 or 1996 Porsche and commenting that it had more "usable horsepower/torque". This car has lots of "unusable" hp/torque for a novice/average driver like me.

This reminded me of a personal experience few yrs back. I found out about this little track north of Edmonton that offered bike track days, so i took my S1000RR. It turns out it was built for carting but big enough for bikes, I had a super fun time, but the amount of power my bike had just couldn't be fully utilized because of the track size and layout. One lap I tried hitting the straight (1/4 mile) harder (hit 200km instead of 185-190)and missed my braking point and nearly sh*t my pants with the rear wheel in the air braking so hard for a hairpin! Anyway, I thought that was a decent anecdote to the "useable power" idea.

[SMGCFP]

Originally Posted by Sedan_Clan

You're overthinking driving. Sure, it can be overwhelming at first (...just like anything else that requires skill.....racing bikes, extreme snowboarding, tactical shooting, etc.), but time and practice will get you there.

Respectfully disagree. No other cars out there...sure, I'd have the courage to practice away. I'm not overwhelmed by not having the DSC off, it's that the car is RWD, and on an imperfect road, one mistake and people are hurt or dead. Now sure, I can drive my morning commute with the DSC turned off and be fine (I drive in MDM all the time), but hit an exit ramp with a sweeping turn at 85 mph...nope, not without the DSC on. Someone could've dropped oil or brake fluid all over road right before me.

[tropicalypso]

I have yet to take MDM off. I want to find a large open area to give it a go... but such places are far and few between (and there is a significant police presence in my area).

[FormulaMMM]

What you've heard is right.

Every M car to date requires TC off for "full access." I know of no exception. Even the F90. I thought I'd give it a whirl in MDM. Lasted about 1/2 lap.

The problem with BMW TC is that the threshold for intervention is way, way too low. It senses you're in trouble long before the experienced driver (especially DE driver) actually is. This is probably most apparent on corner exit. An experienced driver will be able to manage the power and begin accelerating well before the car will give it to you.

I'd rather stay home than run MDM on my GTS on track. No hyperbole. It's not tenths per lap, it would be seconds. It cuts into the potential dynamics of the car to that degree.

I really hope it's something BMW evolves and gets right for the upcoming gen. They're way behind in this department. My trailer park track car has a wonderful 5 stage system. I can run that in "Race" TC mode and equal lap times of fully off.

Disclaimer: Don't take risks. Don't disengage TC unless you're experienced and/or in a safe environment to experiment. Autocross might be a good place to start if you're in high population, can't get space to yourself. I was lucky enough starting out to often have most of my home track to myself. I turned off TC (after learning with it on), and gradually increased pace, experimented. I was hooked inside of a day. It was like I discovered a new car.

[matty088]

mdm and dsc is complete waste of time. I mean i get it for when you exploring the limits of the car on the race track for the first couple times. But the driver should ultimately drive the car....not the car driving itself.

[Sedan_Clan]

Originally Posted by SMGCFP

Respectfully disagree. No other cars out there...sure, I'd have the courage to practice away. I'm not overwhelmed by not having the DSC off, it's that the car is RWD, and on an imperfect road, one mistake and people are hurt or dead. Now sure, I can drive my morning commute with the DSC turned off and be fine (I drive in MDM all the time), but hit an exit ramp with a sweeping turn at 85 mph...nope, not without the DSC on. Someone could've dropped oil or brake fluid all over road right before me.

What exactly is there to disagree with? COMPREHEND what I'm telling you in response to your statement that I quoted. You likened video game dynamics to the real thing (...which it NEVER will be), claimed you couldn't control the car, etc. I'm telling you that time and practice will eventually rectify your lack of ability. Never did I suggest using public roads to accomplish that. Furthermore, every individual started somewhere in terms of ability. Ask any of these guys who regularly track their ///M's what it was like when they first began tracking cars, and how time, patience and practice eventually made them better. I race bikes far more than cars, and I can tell you that time, patience and practice will get you there. I track a V4 Panigale; a very powerful bike......but I surely didn't start there. I built up my ability over time on 600's and my 848 track bike.

[captainaudio]

If the traction control is constantly intervening in normal driving situations you are probably doing something wrong. c

Speed is about smoothness and keeping the car balanced. I find it to be a great track exercise to push the car with all of the nannies on as you perfect your racing and sight lines, braking points, etc. As you get smoother the nannies will get less intrusive and you will be faster, When you get to the point that you can do consistent fast laps with little invention of the traction control you can start driving without it while keeping the smoothness you developed while driving with it on. The 'ragged edge" should be approached, carefully and systematically.

[minn19]

Originally Posted by captainaudio

If the traction control is constantly intervening in normal driving situations you are probably doing something wrong. c

Speed is about smoothness and keeping the car balanced. I find it to be a great track exercise to push the car with all of the nannies on as you perfect your racing and sight lines, braking points, etc. As you get smoother the nannies will get less intrusive and you will be faster, When you get to the point that you can do consistent fast laps with little invention of the traction control you can start driving without it while keeping the smoothness you developed while driving with it on. The 'ragged edge" should be approached, carefully and systematically.

Normally I'd agree with this, but BMWs MDM is too intrusive and even "smooth" experienced drivers/pros would be getting intervention.

[AO08BAS]

Thanks for the replies everyone!
I see the DSC light on my dash every 5mins with spirited "in town driving" Keep in mind I live in the UK and the roads are not great especially in winter.

I would consider myself a semi-competent driver as I have had an M car as a daily since 2005. But I am yet to drive my F80 with everything off despite having it now almost 8 months.
I just wanted to gauge how much of a difference it would make to my day to day driving if I turned everything off, going by the responses it wouldn't make much difference unless it is really kicking in for no reason at all at the moment and being more of a hindrance than a driving aid as such.

[shortseller]

Originally Posted by ZeCP

Thanks for the replies everyone!
I see the DSC light on my dash every 5mins with spirited "in town driving" Keep in mind I live in the UK and the roads are not great especially in winter.

I would consider myself a semi-competent driver as I have had an M car as a daily since 2005. But I am yet to drive my F80 with everything off despite having it now almost 8 months.
I just wanted to gauge how much of a difference it would make to my day to day driving if I turned everything off, going by the responses it wouldn't make much difference unless it is really kicking in for no reason at all at the moment and being more of a hindrance than a driving aid as such.

If you drive exclusively in sport+ and are not able to manipulate the gas peddle in a moderate way, meaning not like an on/off switch, you will have too much interference with the DSC interfering. As you go down to sport or efficiency, it get even easier to keep the light off but your driver experience gets watered down as well. Find some backroads and get a feel for your comfort level within the multi drive settings. The car is a beast, you owe it to yourself to learn how to fully enjoy it.

[matty088]

ill be that guy.....but this is a "generational" type issue.

[NYG]

Originally Posted by minn19

Normally I'd agree with this, but BMWs MDM is too intrusive and even "smooth" experienced drivers/pros would be getting intervention.

Agreed. Even when you're not going hard MDM intervenes often.