Like many, I'm annoyed by the crude implementation of the MINI traction control logic. If the system detects so much as a friggin' grain of sand on the road it immediately imposes a mandatory 1 second throttle time-out. Does anyone have a theory on this? Do other cars use a similar logic? I was expecting the system to be completely transparent like ABS or DSC.

Seems to me, the proper way to implement traction control would be to engage the brake on the first wheel after significant (say, 1/4 revolution) slippage has occurred. Later, if needed, it would engage the brake on the other wheel in the same manner. Finally, *if and only if* substantial brake force is being applied to *both* wheels for a substantial length of time (say 3 seconds) the system could quickly reduce and reapply the throttle until equillibrium is reached at a setting requiring only one brake (one brake is needed for optimal accleration). Result: Faster acceleration than any fancy differential could ever provide. An algorythim like this would make limited slip differentials obsolete and then some. And the hardware is already there -- they just didn't program it! What do you guys think?

 

Well, I gave up on you guys and decided to consult a friend who worked on the Bosch system for the C5 Corvette. He told me that the C5 system polls the wheel sensors at 25ms intervals for ASC but only 100ms for ABS. ASC therefore engages very quickly (4X more responsive than ABS) and is set to engage with only 10% wheelspeed differential. Immediately upon engagement the timing is retarded to reduce power by about 10%. Further power reductions follow as do brake applications but my friend does hardware, not software so he didn't have the complete algorythm handy.

His explanation for the power being cut first was that the power can be reduced instantly by very exact amounts whereas the "perfect" brake setting is found only by trial and error and the system is not fast enough to do so effectively.

I'm guessing someone misplaced a zero and accidentally programmed the MINI for 1% wheel speed differential and 100% power reduction. Let's find out where he lives and go kick his ***.

 

Vespa, THANKS! that's good info about how traction control works. I too have been surprised about how little interest there's been on MCO about this computing/technical function of the cars we drive. Oh well, it's probably on "the other site", but is too difficult to find (and loaded with insults).

Anyway, I agree that the MINI's system is not calibrated properly. My beef has been with DSC, not ASC, but I think the logic and the end result is the same (DSC just ends up having more system inputs than ASC..not that it apparently helps). But I've recently read some reviews of new BMWs where it's said that the DSC was just as poorly set up as it is on the MINI. So, hamfisted programming is likely a part of the corporate heritage on our cars. Too bad. This doesn't bode well for the software fix/upgrade that I've been wondering about.

 

DSC? I don't know that I've ever even engaged DSC. What's your complaint with it?

 

>>DSC? I don't know that I've ever even engaged DSC. What's your complaint with it?

You may not have it...but since you seem to have an S with the Sport package, you probably do. Dynamic Stability Control (DSC) replaces regular traction control (ASC) on the cars that have it. DSC is activated by changes in the car's momentum from the intended direction. I know that there's a better way to describe this... When activated, the DSC system cuts power to the appropriate wheels to try to bring the car back to what the computer perceives as the intended direction. It's not simply activated by loss of wheel traction.

Maybe you have DSC and have been thinking of it just as ASC? Again, check out the thread on "Who's Liking Their DSC" where there's an active discussion of the pros and cons of this system.

 

I dont know the mechanics of it all, but I do know that dry pavement my Mini runs a lot better with ASC off although on rainy days if I dont have it on I wheel spin all over.
I didnt know it paused the acceleration I always thought it was a computer based type Limited Slip Diff.

 

I saw that thread about "Who's liking their DSC?" but didn't understand why folks were blaming the DSC rather than the ASC. I have DSC and it's my understanding that it intervenes only with lateral and yaw movements. I suppose I could be triggering it by powering through a corner but I think even in that case the ASC steps in to prevent wheelspin before the wheelspin can cause enough sideslip for the accelerometers to detect the unwanted lateral drift. I'm just guessing here, seems everyone else blames the DSC. I wonder if the ASC is maybe more "tolerant" on cars w/o DSC and hence DSC gets the bad rap?

 

Vespa,

Wacky concept pic on your sig!

 

That´s very interesting.

The first time my ASC came on I actually though my car had a failure of some kind and took it to the dealer (and never found anything wrong - I got so angry).

After a couple of times more I actually got to the conclusion it was the ASC working when I was abusing the car..

It feels very disconcerting though but I never turn it off. If it´s there for my safety I´ll get used to it.

 

the asc does use the brakes on the wheel(s) that spins. if it isn't enough, then it cuts off the engine's air intake and then the fuel injection is reduced.

 

>>the asc does use the brakes on the wheel(s) that spins. if it isn't enough, then it cuts off the engine's air intake and then the fuel injection is reduced.

I'm not sure that's correct,
but first a few comments for vespa on why you had no immediate response.
I love MCO a lot, it's a great site, but sometimes it's hard to find certain posts unless you catch the thread when it is first posted. If you don't get a response, just add another post to the thread to bring it back to the front.

Now, to Beermasters comments:
I do believe ASC will ultimately apply brakes, but before it does that power is reduced. That however I believe is not done by messing with airflow or fuel flow or injection, but only by working with the timing.

Regarding DSC and ASC:
As some have stated, DSC kicks in at different times than ASC and in response to different sensors: yaw and lateral acceleration, vs wheelspin for ASC. They could potentially kick in at the same time.
All MINIs have ASC, and if you have DSC, then ASC is integrated into it. I think some folks have beef with ASC, because they notice a power cut under some conditions that does not occur if DSC is turned off, but that is only because when deactivating DSC in cars that have both, you also deactivate ASC.
You don't activate DSC if you have it. It is on by default unless you turn it off.

One of the problems may be that ASC is probably calibrated for slippery, wintery conditions where you need a much faster response and can gain a lot by cutting power, but then this is not a nice thing to have during dry, sumemr driving.

In an ideal world, you could do two things to improve the MINI's ASC system, in my view:
1) have a switch to alternate ASC between STANDARD (for dry or summer condition with slower response) and WINTER (fast response of ASC the way it is now)
2) automate this switching by using information from the external temperature sensor, and/or even the rain sensor from the windshield wiper, or based on whether windshield wipers are on.

 

Wow. Surprised to see this thread come back.

Anyway, yeah, even though ASC works the brakes 4X faster than ABS it's still not fast enough to be highly effective. Timing changes on the other hand can be implemented instantly. ASC does eventually use the throttle and will even apply gas if, for example, you downshift on a slippery road.

I have absolutely no use for ASC and hopefully never will. I sure wish there were a "sport mode" or some such manner of disabling ASC without disabling the life-saving DSC.