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Opposite Lock: DSC OFF

How-To | November 22nd, 2011 by 26
Z4 35iS inside wheel lift

Loved by some and greatly feared by others, the “DSC button” polarizes fingertips. Many now refuse to buy a car without DSC or “Dynamic Stability …

Loved by some and greatly feared by others, the “DSC button” polarizes fingertips. Many now refuse to buy a car without DSC or “Dynamic Stability Control,” while many refuse to buy a car without the ability to defeat it. What is DSC, how does it work, and when – if ever – should you push the button to turn it off?

Dynamic Stability Control, as BMW brethren know it, is a complex electro-mechanical system that steps in to control the direction of a car if the system detects loss of control. There are many examples of this technology across automakers, each with their own unique and often overstated acronym. Like any other technology, the quality of the system varies across automakers, but generally speaking, they all do a good job of correcting for loss of control. In fact, these systems have been found so reliable and consistent in reducing automotive collisions that they are now required by law in some countries.

Opposite Lock: DSC OFF

In brief, here is how it works: A central control unit continuously takes in information from various sensors around the car. Factors such as wheel speed, throttle or brake position and steering wheel position are used to determine the directional stability of the car. If the system detects excessive yaw rates (oversteer) or insufficient yaw rates (understeer), the control unit will fire out electronic orders to adjust ignition or fueling and grab individual brake discs at any of the four corners to bring the car back onto its intended course. DSC really is an amazing piece of engineering, and in practice it is quite impressive. You can literally throw a car into a corner on a slippery surface, and watch as the system sorts things out.

This begs the question: how on earth did we survive a single car ride before the invent of Dynamic Stability Control? The answer is as simple as the question is stupid – drivers used to apply the tenets of car control to either prevent, or correct for a loss of traction at the front or rear wheels (understeer or oversteer). Whereas cars are beginning to drive themselves, there was a time not so long ago when drivers drove their cars.

Opposite Lock: DSC OFF

All play, no work makes Jack a lazy boy, so I signed up for eight hours of volunteer flag marshaling and standby medic duties at a track event on Sunday. Normally behind the wheel, I found it a unique and interesting experience to watch things from the sidelines. It was exeedingly easy to see when a car was about to lose control, whether the driver was reacting appropriately and whether or not he would survive another lap before being passed – or spinning off the track altogether. This experience was, in fact, my inspiration for writing this edition of Opposite Lock, because the topic of DSC and whether or not to turn it off – particularly on track days – is worth discussing.

Let me be frank: driving a sports car on the racetrack while keeping DSC on is a lot like having sex wearing a condom. It’s still great, a lot of fun, but you’re missing a certain intimacy with the car. There is a safety layer that is isolating you slightly from the experience. Driving at the limit with DSC off will land you with the munchies and in need of a smoke. Of course, such untamed indulgence comes with more risk – I’m talking of crashes not children. And thus, whilst driving with DSC off you must be ever mindful and respectful of the weighty responsibility you have behind the wheel – the very welfare of your car and your personal safety depends on it.

Ironically, I tend to feel safer driving at the limit with DSC off. This is not proof of my insanity (there’s plenty of that elsewhere); there is actually a logical thought process behind this. When pushing to the limit with DSC on, the computer system is constantly reacting, reining in the action and adjusting for the attitude of the car, while you give more basic, large inputs; the finer corrections are made by DSC. What can result is a false sense of security. As you drive faster and deeper into corners, you continue to build speed, while aloof to the limits of grip and subtle dynamics of the car (because you haven’t felt them). When you finally get in too hot, you will not be aware of it until it’s too late. The car’s dashboard will light up like a Christmas tree, and you may even hear audible alerts (in some cars), but the fact remains you are in over your head and neither you nor the DSC can defy the laws of physics. You may well find yourself swinging from a tree, or sideways in a ditch, with roadside assistance on the line.

Opposite Lock: DSC OFF

Long ago, I made a conscientious decision to always get a feel for the raw, mechanical soul of each car I test. As I approach the limits of grip, there are no surprises. Most cars predictably understeer, but can be coaxed into oversteer through various means. While prodding the limits, you get a feel for exactly what the chassis and suspension are doing. The contact patches travel straight through the seat and steering wheel, into your hands. The weight and handling balance of the car shows itself in full view. There are no tricks or surprises, no flashing lights or ringing bells: just man and machine.

If you’re pushing a car to its limits with DSC on, you will inevitably become a passenger once you’ve reached or exceeded those limits (or in most cars, even approached them), and that is precisely why I prefer driving at the limit with DSC off. You, the driver, are in control, and there will never be overlapping corrections while both you and the computer work to correct for over or understeer, trimming your line through a corner.

Consider another analogy: think of DSC as a form of training wheels. Initially, training wheels are helpful to get a feeling for your bicycle. You’ve graduated from the tricycle, but you’re not quite ready to tear up the back yard with handlebar streamers flowing in the wind. As a safety net, the training wheels allow you to gain the basic concepts and principles of riding a bicycle so that once they’re removed, you build on what you’ve learned – and I look at DSC much the same way. It’s allowed you to learn the racing line. It’s given you a basic feel for the car’s handling and where you’ll approach the limits – but until you’ve turned it off, you have not truly driven your car, in fact you’ve likely been driven by it. No one in the Tour de France is running training wheels and here’s a hint: it’s not for reasons of aerodynamics.

Opposite Lock: DSC OFF

So, when do you turn it off? Only when you’re ready. Don’t be peer pressured into it – your friends will not pay your bill at the body shop. Grow as a driver until your comfort zone eclipses the button. When you’re feeling confident, seek out a safe, isolated place to push and prod your car to its limits. A closed off parking lot, skid pad, landing strip or racetrack would be ideal. Do not attempt to learn car control on public roads. Once the training wheels are off, you will be amazed at how steep your learning curve becomes.

Interestingly, when driving at the limit with DSC on, the rear brakes can be so heavily used by the system that they may even begin to smoke! Since the rear brakes are frequently squeezed to manipulate the vehicle, you will also see significantly increased brake wear if you drive with DSC on during at-the-limit driving. Yet another reason to turn it off, and learn the nuances of car control.

As an accomplished driver, you will find your fastest lap times with DSC off. When traversing deep snow, you will also find it important to turn DSC off, so that your drive wheels can clear snow and build momentum – something not possible with DSC on. Finally, when the punk kid with hat-on-sideways revs up beside you at the light – turn DSC off. You will have a great opportunity to teach him about the laws of physics and the limits of grip.

Opposite Lock: DSC OFF

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Tell us YOUR thoughts on DSC in the comment section below!

  • Russell Chapman

    Another great article Shawn. Some of the new cars being designed now are being developed with the assumption that DSC will always be on, and the “native” or raw handling will be deliberately flawed.
    Even driver’s cars like the 458 and the MP4-12C have their handling compromised to work better with DSC (and consequently are faster around Fiorano and Dunsfold respectively with DSC on). 
    It’s sad to think a whole generation of drivers will never know how “opposite lock” works (and entertains) outside their PS3/XBox.

    • Shawn

      Thanks Russell, much appreciated.  

      The MP4-12C is a great example of a car designed to work better with it on.  In fact, I read an interview where a lead engineer on the car questioned why you would want to turn it off.  Clearly this man is not well versed in the joys of car control – he is more likely a genius stuck behind a desk.  No question they’ve made the car work – it’s fast – but soulless according to most reviews I’ve read/viewed.  I’d love my own seat time to complete my opinion on the car, but from what I’ve read alone, I’d opt for the 458 any day.

      • UberMpower

        I watched a documentary on the MP4-12C and I can see why the car could be soulless, I know Ron is a genius but the factory is so stark and sterile its more like a hospital, i know allot of car manufacturers have factories that are very clean but this was on another level completely, so much so one worker commented that if anyone had an accident they would rather be operated on at the factory than the hospital, there doesn’t seem to be any focus on the history of the mark either,  

        I can see how Ron’s philosophy could effect the car, he is so anal about everything I would go as far to say he has some compulsive disorder where everything has to be perfect, he was moaning about a floor tile that had been replaced and it pee’d him off because it was a slightly different colour,

        I think because the F1 car is very technical and built to get around a lap quicker than everyone else and this philosophy they put into the road car, result a car with no soul, 

        The car is as you say a good example of driver aids and traction control systems, the car will even brake individual wheels to get you around a corner faster, which is all well and good and it will get you around a lap faster (unless your a racing driver or very talented) but its not as much fan as switching it all OFF,

        There is obviously a place for these systems as not everyone wants to drive in a hardcore manner, my mate has a Ferrari 430 and openly admits he cant drive to save his life so for him the driver aids are always on,

        For me the DSC is a good aid for when the road conditions are bad i.e heavy rain or ice other than that its OFF at all times……!!!

  • Russell Chapman

    Also, I think there might be an on/off typo in the first line of the rear brakes paragraph.

    • Shawn

      Thanks, caught that after posting – but I appreciate your correction!  Keeps things tidy around here.  

  • Rdaugher2

    I generally turned off DSC at the track once I got comfortable with a car.  I was told that if it flashes too much, you are driving the car wrong and may not be able to understand what you are doing wrong.  On the street I don’t turn it off but occasionally use DTC or MDM modes to have more fun yet with a safety net.

    • Shawn

      Rdaugher2,

      I think most readers will resonate with your comment.  M Dynamic Mode is a great intermediate that allows you to explore more performance without totally letting go of the safety net.  

      As far as the light flashing too much, I was recently told by my good friend and automotive journalist / racer Brian Makse that Porsche’s version is so well designed and finely tuned that you can literally have the car in a controlled drift without any interference.  But without touching any buttons, try that in an abrupt way and the system will intervene and prevent any sliding.  Pretty impressive tech.  

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  • Giannis

    Very interesting article. I too turn it off on a track but also turn it off when on a spirited drive out, took me more than 6 months of owning the car to actually turn it off though. I’m nowhere near the limit when on a quick mountain road blast but i still find that my Z4MC’s DSC is far too sensitive and restricting to enjoy the car, and i dont mean hang the tail out on turns…

  • Georges

    I used to drive my M3 wihout DSC since 2 years but few months ago, i try my e46 without DSC on a montain road, it was amazing … The sound … The power … The all without going faster than 30 mpg ! It was my best bmw trip of my all life ! Until i reached the Highway … I forgot to put the DSC back and as soon as i enter on the freeway i pull down quickly the accelerator to reach the 60 mph and avoid a car … In 0.1 sec i realize than i was seriously drifting ! and i finshed out of this small road.

    What i want to say is : Never, i say never try to play with you car on public road ! Because all not depend of you ! As shawn say ! Thx for this article !

  • Ulrich Diederich

    Funny thing is the dealer can tell. I recently had my car in for service and after scanning my key the advisor said “so, you drive with DSC off?”. Wow!

  • http://twitter.com/EndrasBMW Endras BMW

    Excellent article Shawn! Now if only you would of reminded people how to turn DSC off! You’d be surprised how little people know. =D

    • Shawn

      Thanks!

      For those who don’t know, I will let them explore! 

  • http://www.tashodi.ca Jon

    Funny, I was having same discussion at the same event on Sunday.  My E46 has an open diff and in the wet it is impossible to drive quickly without the E-diff.
    You should’ve seen my rear rotors, they were blue from all of the braking.
    Once it dried I was able to turn DSC off put in some really fast laps without spinning one tire uselessly.
    ~Jon

    • Shawn

      Hi Jon,

      Good to have your comment here – I would recommend also turning DSC off in the rain.  The E-diff in the E46 is quite ineffective, you will find faster lap times with it off, feathering at the limit of grip.  I’ve driven open diff BMWs quite a bit on rainy track days and it hasn’t slowed me down beyond the limit of inside wheel grip.  Also a lot of fun and a good challenge, which is what it’s all about.  

      Cheers!

  • Bigk

    Fantastic article.. thanks so much for it.  Great to hear that there are true gear heads like us left out there.  

  • http://twitter.com/jamesbachici James Bachici

    Great piece Shawn! It brought back fond memories of my first DSC off “escapade” in my 92 325i when I attempted to enter a 90 degree corner, in the wet carrying just a tad too much momentum resulting in a spin. All was well but I left it on for a few more months after that. Once the initial shock wore off, I turned to the abandoned parking lot practice sessions with friends, food and orange traffic cones! Good times :)

  • Ben

    An extremely informative and accurate article. I’m in the turn DSC off when I put my seat belt on group and I’d have it no other way.

  • Ivey McAllister

    I just have to say wow! Just bought a 2007 Alpina B7 in may. This is my first newer model BMW. Anyway when I would press the car hard I could tell it was holding back. So I read my manual in detail as you would guess I found out how to turn the DSC off. After putting my blank beauty in manual mode with DSC off I realized I was not ready for what my B7 had to offer. Now in conjunction with your article I will surly learn more abou my car before I do that again. The interesting part I this was just two days ago this happened. Great article! Thank you!!

  • ///M & /////AMG All Day

    I basically leave the DSC on all the time, but when I want to set up launch control or just act dumb in an empty parking lot with my brothers M6, I turn it off :)

  • ged

    driving along motorway at over 70mph and dsc comes on when it goes faulty is not a safety feature to brag about

  • Eugene

    DSC off = FUN on :)
    I call that button the ‘FUN ON’ button ;)
    It is always OFF in my case, before seatbelt is buckled ;)
    Great article !

  • Eugene

    DSC off = FUN on :)
    I call that button the ‘FUN ON’ button ;)
    It is always OFF in my case, before seatbelt is buckled ;)
    Great article !

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