Hi all, I was reading a newsletter/rag from Bavarian Autosport (www.bavauto.com) and it was talking about getting going in the snow, and how the DSC makes it a problem because of the traction control. They say that all BMWs have a mode where the ABS features work (like an electronic LSD) without the traction control enabled. The way to get it was to hold down the DSC button for about 10 seconds. The DSC light will go on while the button is held down, and eventually go off and your in the "half-way" mode. Well, I tried it in my Mini, and the light behaves the same. But I had my little girl with me, so wasn't about to go find a place to test it out.....

Anyway, anyone else ever hear of this feature, or use it on thier BMW?

Matt

ps, I looked, and the fall newsletter isn't up on the web site yet. And wouldn't you know it, I noticed what remained of the article after I'd started a fire with the rest of it!

 

You may be talking about ASR (Acceleration Slip Reduction), which uses selective braking to stop wheelspin from acceleration (the analog to a LSD). The problem with ASR is that it applies the brakes to stop a spin of the wheel due to traction being lost. A traditional LSD shifts torque from the spinning wheel to the non-spinning wheel. Hitting the brakes (to stop the spinning wheel(s)) would seem to increase the total time spent getting from Point A to Point B.

If we are talking about ASR, I was under the impression that it is always on at low speeds (<35 mph); so, I don't know about the press of the DSC button for 10 seconds.

 

ASR? Perhaps that's the generic term for the technology, but I think in MINIs and BMWs it is called ASC+T (Automatic Stability Control + Traction). It's the technology that most of us complain about when it kicks on in dry weather during hard accelleration.

I for one hope that the 10-second switch thing turns out to be true, but I won't hold my breath!

We want DSC minus ASC+T!

 

Hah I read that same newsletter a couple of days ago and was wondering the same. Would be interested in knowing this as well--no snow where I live!

Richard

 

>>Hitting the brakes (to stop the spinning wheel(s)) would seem to increase the total time spent getting from Point A to Point B.<<

Visions of train heading towards my door as the traction control is kicked in... :-O

 

I've tried the 10 second thing. It does something, I think, but I'm not sure exactly what. With my lack of torque and bad clutch, I cannot really test things out that well.

Come on, folks... try it! Hold the DSC (ASC?) switch for 10 seconds until the light goes out and tell us what you think happens.

 

Okay, I know what you are talking about and here is the soultion:

BMW:
Pressing the DSC-button only deactivates the traction-control, meaning you can burn rubber like hell if you want to, but you cannot drift in a corner. Only the traction-control light will get lit.

Pressing the DSC-button for longer than 5sec deactives traction-control and the DSC-system. No electronic system will get you back on the road if you are making driving mistakes ! This mode will light up the traction-control light AND the parking-brake light (but not red, it will light in yellow like the traction-control light).

MINI:
Pressing the ASC/DSC-button deactivates traction-control and DSC. There is no possibility to deactivate only traction-control. Only the traction-control-light will be lit yellow.

 

where are you getting this informatin. It seems in my mini that if I hold the dsc button down for a short time then release it the dsc off light comes on then goes out.

 

a) I read nearly all handbooks
b) I work with BMW/MINI Germany
c) I have driven nearly all possibilitys for DSC/ASC

 

VERY INTERESTING.

Now how long before someone figures out how to wire up a toggle switch (I have one blank ) to deactivate only the traction-control while still leaving the DSC on???

Do IT!

 

Nice idea, but the problem is that DSC and traction control are hardware coded in your ECU. Believe me, if I could do it had already been done since I onw my little racer...

 

DAMN! Bloody Cavemen!

Maybe this is the secret to MTH's DSC tuning.

They just disable traction control, but leave the DSC enabled?

 

Nö, since I am very close to MTH I can tell you the following.

The DSC-mod of MTH ist that traction-control is allowed 100Nm of spin before kicking in. DSC in not in any way affected.

 

Man, I'm getting shot down left and right.

Guess I better not keep trying to out guess the DR!

Can you please give us any more details to how MTH changes the Traction Control and/or the DSC????

 

What do you mean... the software is coded to allow 100Nm of spinning before kicking in, that's all !

 

Oh. Sweet!

So what's that equate to for us poor saps here in the states using the standard system of measurement???

100Nm = ???

 

100 N•m is 73.76 ft•lb.

 

What is the reason for allowing the brakes to act as a kind of traction control instead of the engine?

 

If you think of what a clutch type LSD does, it applies torque proportional to the difference in axle speeds, and has no effect when the axles are going the same speed, fine if you're going straight.

Having the motor dump power with an open differential will do nothing to prevent spin of one wheel over another, just make you apply less total torque.

having the wheel brakes defeat wheel spin is like a clutch based LSD, but it's happy if the wheels are at slightly different speeds, like a turn.

The use case for keeping the power is if you're in a situation where maintaining some slippage is good, like if you have to dig through some sand or snow to get traction from a deeper layer....

Matt

 

Ahhh........so it can act on each wheel independently. I got it.

 

Here is what I found out this morning. I have a 2006 MCS with DSC and LSD.

I held the DSC button down for 10 seconds and the light went off. The streets were wet this morning so it was easy to break traction. ASC-T still kicks in and cuts throttle when both wheel start spinning. I was also able to do a sharp corner and DSC kicked in as well.

I did have a feeling though that the ASC and DSC kicked in a little later than usual. So my hunch is that this is a track mode where the thresholds are raised. But I have no data to prove that.

 

I don't think holding it down does anything but turn the light back off; it probably thinks something fell against the switch, or it's stuck. :-)

 

Yes I've heard of it... I have it on the BMW... what you're describing sounds like DTC mode.

On BMWs you just press the DTC button once and it'll enable DTC mode. basically what you're describing... and if you hold it for 3 secs or more it'll disable DSC just like in the MINI.

Let me get some links that describes it better....

http://forums.e60.net/index.php?showtopic=17613

http://forums.e60.net/index.php?showtopic=19256

 

I tried the same thing with the same results. When the tires broke free, the DSC light flashed and traction control kicked in.

 

I was at the track yesterday, when I hit 170km (105mph), the traction light (DSC) lite up and stand on. I tried to push the button to activate it back, nothing, the light still stay on. Until I shut off the car and restart it, then the light went off. But once I go over 170km (105mph) again, it light lite up again. Anyone know what is that? I recently install a Quaife LSD and Stage 4 clutch with flywheel. Anyting to do with thoese 2 mods?