urbo73

A bit confused with DTC and DSC over here :'(

According to the manual, DSC includes DTC (traction control) and DBS (dynamic brake stability). So DSC provides traction control as well as brake control to help keep the car stable when in an over/understeer, etc. Basic stuff I understand.

What I don't understand is what is the purpose of just turning on DTC (by briefly pressing the DTC button)? The manual just says that with DTC you have limited DSC up to a certain speed - I think 45/50mph, that it's useful in snow, blah, blah. Why isn't DSC useful since it also has DTC.... Hmm...

I don't get it. I understand DSC nor no DSC (by holding the DTC button to turn it off). I typically drive w/o DSC since I like to be in control. But anyway, that's just me.

But why/when would I want DTC and not DSC? I can see where I would want DSC and where I wouldn't want it (i.e when I WANT to spin my wheels), but what's the point of having JUST DTC? What does DTC do that DSC (which has DTC) can't? It makes no sense, unless DSC employs a WEAKER DTC. It's just weird.

skaffa

There is an other post of this but briefly:

DSC control car's way of direction by braking individual wheel e.g. if car is under steering it will brake inside curve rear wheel. If car over steer then it will brake outside curve front wheel.

DTC is traction controll for driving wheels.

Skaffa

paasan

DSC "includes" DTC. DTC is a _restricted_ mode of DSC where wheelspin is allowed. DSC _stability_ ("anti skid"/over-understeer) functions are still maintained, while a lot of wheelspin is permitted.

DTC isn't really activated - in principle it's just a part of DSC that is temporarily deactivated/restricted.

Iceman

When you turn on DTC, it only controls the rear axle. DSC controls all four wheels.
Driving in snow can be one of the situatons where it is helpful to turn off DSC partially.

urbo73

Hmm. For some reason I still don't get it. Or the wording in the manual is crap. DTC is for traction control and part of DSC. I understand all that. If I only enable DTC, thus limiting DSC up to 45mph (according to the manual), essentially what you guys are saying is that I *DON'T* have traction control anymore as my wheels are free to spin. It's like some BS system I don't understand. DSC on or DSC off makes sense. I still don't see what I get by having just DTC vs. no DSC at all. And I guess the answer seems to be that I have all the wheelspin I want, but limited DSC functions. That I guess makes sense, but the manual sure doesn't. Also the fact that it allows wheelspin yet it's called DTractionControl is an oxy moron .. What traction control? Hmm..

So:

DSC = DTC + DBC at all speeds (on or off per user preference)
DTC = wheelspin + DSC up to 45mph (on when driving in snow and you want wheelspin + some DSC)

Why can't BMW make this more obvious if that's the case in their manual.

Also Iceman says that DTC only conrols the rear axle. Now this means DTC only = wheelspin + DSC up to 45mph *only on the rear wheels*.

So in the end, to me it sounds like DTC only is sort of useless if this is the case. Either I have DSC on or DSC off fully. I don't see what I really gain by having only DTC with free wheelspin and limited DSC on only the rear wheels over just no DSC at all. That limited DSC on only the rear wheels? Sounds like it. And what is that really?

I just see it creating a driving nightmare where I don't know how the car will react. I'd rather know so I'll always turn DSC on/off fully as needed

E60Speed

For a safe ride DSC

If you want to slide around a bit and have some fun, but still want the computer to help if you get it wrong, or need some wheelspin in the snow/mud = DTC

If you know what you are doing and want no computer help if you do something wrong = all off

Iceman

urbo73,
if you are so confused, just don't touch the button!
Leave it on!!

urbo73

Iceman,

It is confusing, and I just want to understand (being so anal and all ) if my final post above is correct.

Driving wise, I'm not confused as I used to do SCCA racing. So I never even use DSC really (I have to remember to turn it off each time) . I can control my car. But I want to know how everything works, and also for those times when my wife is driving

Iceman

Iceman,

It is confusing, and I just want to understand (being so anal and all ) if my final post above is correct.

Driving wise, I'm not confused as I used to do SCCA racing. So I never even use DSC really (I have to remember to turn it off each time) . I can control my car. But I want to know how everything works, and also for those times when my wife is driving
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I have total control on my car too, but allways have it on. I suggest you take part in a drivers training, or test it yourself where it is secure.
DSC is not causing any trouble. When you do something wrong, the system takes over control, sometimes you don't even notice it, and you don't need to do anything. When you turn it off, you need to do everything yourself. If you get in trouble, in over- or understeering, you don't have any help from the system. On public roads there is not allways enough space in between you and the car next to you, so you can be the best driver in the world, but when you notice the trouble and start to react it might allready be too late. Therefore you want DSC to be active in regular "daily" driving, because the DSC reacts waaaay faster than you can! Having it off is not a sign of somebody who is a good driver...
On track you want to turn the system off completely, so that you can drift.
In snow you will find a lot of situations where the DSC would not allow the car to move, but DTC helps. So you turn DSC off partially and let DTC help you.
And yes, DTC is for the rear wheels.

Just don't touch the button, unless you are on track or you drive in snow or on ice.

Hormazd

Since you have feet of snow outside, why don't you test it. You will be able to figure it out. Then you can give us one of your analyses. In dry Southern Cal this is difficult for us.