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Useless Message Poster
02-24-2003, 02:46 PM
controlled the the car even when your foot was off the gas. When I first hit snow on the way home yesterday, I turned the DSC on. I'm driving along in a straight line on the highway in at least 2-3 inches of snow and the DSC light starts blinking. I let off the gas and it's still blinking and the car starts acting like it wants to spin. I left the DSC off after that.

steel
02-24-2003, 02:49 PM
seems DSC works best FOR you when there is variable traction. Even if there is poor traction, if it's uniform, it has been easier for me to drive with it off.

jason2
02-24-2003, 02:50 PM

DSC light illuminated means disabled. Agent7
02-24-2003, 02:51 PM
Even if you disable it, I think there are some override situations like maybe if ABS gets acvitated, it will still activate DSC.

Evangelo2
02-24-2003, 02:53 PM

StoneWalk
02-24-2003, 02:54 PM
Yep, DSC is actually a collection of a half dozen different features including ones for holding rear traction on acceleration, cornering, and also some smarts about trying to control wild changes in yaw even if you're off throttle by applying individual brakes if it sees what it thinks is a spin about to happen.

It does make the car easier to control. I've lapped a wet skidpad with it on and with it off - I could lift throttle and get the tail out 45 degrees and gather it back up with DSC on. DSC off resulting in a full spin if you lifted, and at least my humble opposite-lock skills were not enough to catch it.

On snow, DSC may or may not be good. As I understand certain ultra-low traction conditions you can end up with almost no thrust at all being allowed past the DSC logic when in fact spinning the wheels to move forward would work if you turn DSC off.

That said, I'm in the camp that says DSC on is a good idea for public roads for most drivers.
<br>
StoneWalk, Ventura California
<img src="http://members.roadfly.com/stonewalk/M3lagunaSeca2a.jpg">

StahlGrauM3
02-24-2003, 02:54 PM

Useless Message Poster
02-24-2003, 02:55 PM
work when you're completely off the gas, off the brakes and the car is sliding..It tried to do something.
BTW. When you turn DSC of, it's OFF!!

Useless Message Poster
02-24-2003, 02:57 PM
no gas, no steering and the car starts to lose traction in the snow. The DSC light goes nuts and the cars starts to spin because DSC was freaking out.

Useless Message Poster
02-24-2003, 03:01 PM
brakes were being applied. It almost killed me dude !!

front??? Agent7
02-24-2003, 03:02 PM
Could that have messed up the ability of the DSC to control things properly due to incorrect information being giving to the DSC computer. Was the slick a different diameter, different offset or something wierd?

StahlGrauM3
02-24-2003, 03:05 PM
first...we all have experienced hitting a patch of ice and starting to slide faster than we can believe it....how do you know it wasn't the DSC reacting to that versus the car having perfect traction and your DSC coming on for no reason and causing you to lose traction. Not saying it couldn't happend just questioning.

StoneWalk
02-24-2003, 03:06 PM
My experience is that it's usually a good thing. But you were on snow, which is not necessarily DSC's speciality, and you had one oddball tire up front if I remember the story right. Those two factors may have been enough to confuse DSC into disfunctionality, which is unfortunate.

Yes, what it was probably doing was looking at the driver input on the steering wheel (straight ahead), and then watching the roll sensors on each wheel, and it thought it saw the start of a slide, so it grabbed a brake on what it felt was the appropriate corner to bring things back in line. If it was getting confused data from the non-uniform front tire setup combined with some snow slippage, it may have done more harm than good. Any chance that one slick tire was spinning at a non-normal rate for a moment on the snow?
<br>
StoneWalk, Ventura California
<img src="http://members.roadfly.com/stonewalk/M3lagunaSeca2a.jpg">

steel
02-24-2003, 03:07 PM
Computer went nuts on you - don't mind the "assistance" when it kicks in when it needs to; not sure I like the "impending doom" countermeasures when it "senses" trouble coming and clamps down. Looks like both were happening at once for you.

zoli-007
02-24-2003, 03:12 PM
1st 2 things I do when I get in car after starting it, Sport on and DSC off. Flame me all you want but I dont like DSC.<br><img src="http://zoli007.com/zolisig.gif">

steel
02-24-2003, 03:13 PM
can see that playing havoc with the computer.

Jum Jum
02-24-2003, 03:15 PM
Like StoneWalk says.
<a href="http://www.bmw.com/bmwe/special/smg/download_video/grip.html">Slip recognition video</a>

Useless Message Poster
02-24-2003, 03:27 PM

HomerS
02-24-2003, 03:29 PM
DSC couldn't find traction in either wheel and kept switching back and forth. Basically, I was stuck on an icey hill at a stop sign to a state highway. Solution: turned it off and attacked the hill backwards. DSC has probably saved my bacon more times than I'll ever know but sometimes it's downright annoying.

t.?HomerS
02-24-2003, 03:31 PM

steel
02-24-2003, 03:32 PM
sliding enough to get the computer to clamp on the left rear brake.

marcmc8867
02-24-2003, 03:33 PM
<br>MHM3 (formerly imola cab23)


2003 M3 Coupe
Carbon Black/Cinnamon/Aluminum
SMG, PDC, Premium, CWP, Bi-Xenon, NAV, Width-Adj. Seats, H/K
Aluminum Pedals, Voice Activation, BMW alarm.

Dynashield, Formula One Tint 15% Charcoal.

Eisenman Race 83mm Exhaust.
Supersprint Connecting Pipe w/o Resonator
BMW Euro rotors, cryogenically treated...FRONTS FOR SALE, SEE CLASSIFIEDS

SSR GT3 19's Satin finish w/Bridgestone S03's.
OEM 19's with Continentals...SOLD
SSR Competition Anthracite 9.5 front and rear with 265/35/WR-18 Kumho Ecsta V700 competition tires
OEM 18's w/ Michelin Alpin winters/Michelin Pilot Sport

NAV-TV with Sanyo 10-disc DVD changer.
Valentine One.

Bimmian Carbon Black painted reflectors.
PIAA Xtreme White 9006 fog bulbs.
Silvervision front turn-signal bulbs.
Platinumvision rear turn-signal bulbs.
Bertelsmann M3 car cover.

Not yet installed:
Ground Control Sway Bars
Brembo Gran Turismo brake kit all around


Later on:
Ground Control Coilovers
Sirius Satellite Radio
KVH Industries Satellite TV

ex-2001 M3 Convertible
Imola Red/black
40k miles 5/01-10/02

<img src="http://members.roadfly.org/marcmc8867/03M3 at house-2.JPG" height=540 width=708>

Grimlok
02-24-2003, 04:11 PM
Last year I got stuck in a “surprise” snowstorm with my M. My new Snow setup wasn’t scheduled to arrive for another week. I drove my car home, and put it in the garage for that whole week. I’ll never forget that drive home. I couldn’t get more than throttle, and it seemed like I was trying to stop a locomotive when I applied the brakes. I got home and DSC actually flat out stopped my car on my driveway. Pedal to the floor, and nothing. Little 1/8 turns from the rear wheels and then they would lock up. I turned DSC off and paddle-wheeled it up the driveway. I have had no where near that amount of trouble with my snow set up. Night and day difference.

Hypothesis:
Now, I understand that you were not on the gas or the brake. But, did the DSC freak out right when you let off the gas? Could have been some Lift Throttle Oversteer (just not spinning the car), it just happens that you were going straight. Basically take your foot off the gas with the car in gear and the rear wheels are actually slipping. Spinning slower than they should be while traveling at the speed you were. The car sees the rear wheels traveling slightly slower than they should be and then looks at the data from the front wheels to determine any spin (I don’t think our cars actually have a Yaw controller, just a wheel differential monitor). It sees differing data from the front wheels and assumes that the car is beginning a spin. The result is controlled braking, which in this case, would actually cause you to spin.


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