Re: ASC

[alex.fadeev@xxxxxxxxxxx]

MichaelJAdair@domain.elided wrote:
> 
> Can any one give a good description of the How the ASC traction 
> control works on my 98' M3? 

Michael,
I don't remember all the minute differences between ASC and DSC (far 
better), but basically it monitors wheels speed via the ABS sensors for 
any deltas. Beyond a certain threshold, ASC brain first applies breaks 
individually to the slipping wheel to slow it down. If that intervention 
is not effective, it chokes the engine be closing the ASC butterfly right 
in front of the throttle. Very primitive, but rather effective.
It may or may not also retard the timing, though I may now be stepping 
into DSC territory. 
DSC is a LOT more effective. It measures the steering wheel movement, vehicle speed, transverse acceleration, yaw 
and something else I'm forgetting. 

> When it should be used? 

It is always ON by default when you start the car. 
There is a relatively simple fix to reverse the default behavior to OFF. 
I hardly ever trigger ASC on the street in my wife's '98 car. Thus it 
never bothered me enough to turn it off when I drive on the street or let 
alone permanently rewire it. 
When either one of us tracks or autoXs the car, ASC is always OFF. 
Regardless of conditions (dry, rain, standing water, ice, whatever).

> Does it really work? etc..

Yeah.
Kinda.
You can still spin the car with ASC on. My '95 M3 does not have any 
traction control and I do not miss it.
ASC intervention is also very rough and very conservative. Once triggered, 
it chokes the engine for 2-4 seconds longer than necessary. So when you 
are trying to go fast (on track or autoX), definitely turn ASC OFF and 
learn to control the car yourself.

> Also, how good is this car in the winter? 

A traction control system, ASC included, can not invent traction. All it 
does is help you manage the available traction in keeping the car going 
straight. That is not always where you want it to go, but 90% of the time 
it is. And 90% of the time ASC is good enough to keep you from spinning.
For the other 10%, check you local BMW CCA chapter's schedule and sign up 
for a Driving School. 

> With and without winter sized rims and proper winter tires. 
> Any opinions appreciated.

Unlike TC, winter tires actually _do_ increase your traction in snow and 
ice. Especially compared to the summer M3 rubber that is next to worthless 
in the cold, let alone snow.
If you see more than a few days of snow in your region, definitely buy a 
dedicated set of snow rims+tires!

alex f

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