My first HPDE event was at Brainerd International Raceway (BIR) with North Star BMW in June of 2019. One of my instructor’s final comments was “always make sure to understand the DSC (BMW speak for Dynamic Stability Control) off settings for each specific BMW model”.
DSC? Stability control? Traction control? How do I know if my car has one or both? And what do I do about it before heading on to the track?
I am by no means an expert; it took me about two months to figure out the various settings for the M2 I use as a track car. And four years later I am still learning about how stability and traction control impact the M2 during high-performance driving.
Here are some resources that helped me understand M2 stability and traction control settings.
The owner’s manual is a good start. It will tell you what stability and traction control systems the car has and how the manufacturer describes the function of those systems. Friends with similar vehicles are also a good resource. (And an added benefit – talking to friends about cars.) While online forums often contain useful information, be wary as not everyone online has a clue about what they are talking about.
The best resource is to drive your car with the different settings on and off. But please make sure to do this driving/experimenting in a safe and controlled setting such as at the car control clinics run by North Star BMW. You drive at lower speeds than on a racetrack and are on a road course at Dakota County Technical College that is separate from public roads. Winter clinics are particularly fun because it is easy to feel stability and traction control at work when driving on snow and ice.
Although the terms stability control and traction control are often used interchangeably, it is important to distinguish between them as each system does something different when operating. During the last 6 months, I had a chance to drive (and review the owner’s manuals for) five different BMWs. Each manufacturer likely describes stability and traction control differently. Even cars from the same manufacturer can be different. Our family has a range of BMWs from 1969 through 2019 and each is different. Some of the differences between them are due to the age of the car, newer ones are much more sophisticated, but also the nature of the car plays a role. For example, the M2 is a track-oriented car, while the X3 is more of an everyday vehicle.
The owner’s manuals for our 2018 M2 and 2019 X3 describe the concept of DSC – Dynamic Stability Control as:
Within the physical limits, the system helps to keep the vehicle on a steady course by reducing engine speed and by braking the individual wheels.
The concept of DTC – Dynamic Traction Control is described by the X3 owner’s manual as:
DTC is a version of the DSC Dynamic Stability Control where forward momentum is optimized.
The system ensures maximum headway on special road conditions or loose road surfaces, for instance, unplowed snowy roads, but with somewhat limited driving stability.
1969 BMW 2002
Traction control? Stability control? Never heard of either. Antilock brakes? Sure, you use your foot to modulate the brake pedal, so the brakes don’t lock. Works great. Simple car. Easy to drive and repair. Not particularly sophisticated or fast. But so much fun to drive.
2004 BMW 325i touring
Jump ahead twenty-five years to our 2004 E46 325i touring, with a 5spd manual transmission and rear-wheel drive. No sport package, but still a bit of a unicorn. According to the owner’s manual, a rear-wheel-drive E46 has Dynamic Stability Control (DSC) that incorporates Dynamic Traction Control (DTC) and Cornering Brake Control (CBC) functions. And just one button is used to control those functions. In the E46 these systems are the early versions of what is found in our newer BMWs.
2018 BMW M2
Fourteen years into the future brings us to the M2 with a 6spd transmission and rear-wheel drive. A performance vehicle that is so much fun to drive. And so many different settings – Comfort, Sport, Sport+, M Dynamic Mode (MDM), a traction mode, and finally the everything turned off mode.
2019 BMW X3 M40i
In January 2022 we purchased an X3 M40i. A comfortable and fun-to-drive vehicle, with heated seats and steering wheel, and good exhaust sound. Not as performance oriented as the M2, and one year newer, but with many more buttons to push. The earlier photos show the car with DSC and DTC off. There are also settings for Comfort, Sport, and Sport+ to think about, in addition to more advanced driver assistance tools such as lane change assistance and forward collision warning systems.
2021 BMW 840i
A loaner from BMW of Minnetonka. More of a grand touring car and so wide I was worried about scraping the mirrors when exiting the service bay at the dealer. And lots of electronic settings and controls! The 840i even tried to steer for me, something no car has everyone done for me in the past.
This brings me to the driving aids found in many newer vehicles. In addition to stability and traction control, there are forward-collision warning systems, steering and lane control systems, and other driver assistance devices.
You also need to understand these driving aids before getting on the track as they can significantly alter the behavior of your car during high-performance driving. Think about what might happen if your car decides to resist your effort to ease through turn 2 at BIR.
If after reading this column you dig out your owner’s manual and read up about the traction and stability controls that your car is equipped with, as well as any other driving aids, then great. The goal of this column is to get you thinking about the different systems that help control your car and how they will impact the car and your driving during an HPDE event.
Most important though is to discuss with your instructor or coach the specific stability and traction control settings and other driving aids your car has, and how to set them and use them when on track before you both are buckled into the car, helmets cinched tight and waiting for the track to go hot.