Sudden snap oversteer - no warning

[sameh]

Wait wait wait Voltigeur, it was 40F!!
There are 2 good explanations there:
1) Summer tires losing grip on lower temps.
2) black ice on the ramp

[Voltigeur]

Originally Posted by Ateam

People can critisize me all day for this but this is another example of people not using the best (or one of the best) safety features cars have on them today-Full DSC. If you were that good a driver, you would not at all be troubled by having to correct a simple problem like that.

Why you use mdm on the street should show you its stupid. Sure, this could have happened with full dsc on but chance is less likely.

MDM was designed for track driving for people who were not skilled enough to take their DSC totally off. It was and should not be intended to play boy racer on the freeway. Any type of street driving, even aggressive should never trigger the DSC anyway. We do not have enough low torque where it is preventing acceleration unless you do launches.

Just dont get people that feel cooler in MDM mode

Throw some brickbats why don't you. I've driven cars long before there was DSC to auto-correct controllability issues. I think drivers should learn to drive sans these aids in case they fail - electronic systems *do* fail. I learned to drive fast on dirt roads w/ no modern safety aids - except a seatbelt (lap). I have rallied cars and I specifically stated that I did not 'punch' the throttle: to do so on a public road in MDM is foolish indeed [akin to an NFL player going into a 'club w/ his gun w/ the safety off ], so we agree on that.

The road was clear of traffic at the time and hence I did not pose a hazard to others. And I don't always - in fact not often - drive in MDM. If there had been any road or weather anomalies, or traffic, I would have left DSC on, but there were none.

You shot off your perspective before making a fair assessment of what I detailed - IMO.

[Voltigeur]

Originally Posted by sameh

Wait wait wait Voltigeur, it was 40F!!
There are 2 good explanations there:
1) Summer tires losing grip on lower temps.
2) black ice on the ramp

1) PS2s
2) No black ice / rain - S. TX Well, to be fair, we do get some ice - rarely- here but I change my driving style accordingly. I used to live in a much colder climate and this never happened to me (no M3 but other Bimmers).

[Voltigeur]

Originally Posted by VictorH

I've done this before and I don't think it's systems failure, it's just too much power relative to the available traction.

Location: Munich, Germany
Car: 2008 M3, manual trans, new dealer vehicle
Temp: Approx 35F
Situation: Relatively sharp 120 degree on-ramp onto Autobahn. SA in passenger seat, wife and daughter in back (it's an E92).
MDM on, throttle, normal (I bet your "power mode" made this worse with the more sensitive throttle), as I'm unwinding the steering wheel, I roll in the power a little too aggressively and then wham, I'm sideways. Correct the wheel, wind it out in 2nd gear and get good wheelspin shifting into 3rd. Comment from my wife in back, "what was that?" my reply, "too much power", SA says nothing.

Anyway, I don't think your situation is unusual or indicates any kind of problem with the car, but I bet if you go back on foot and look at the surface there's a reason your rear end let go. Nothing to do with the electronics.

First, Munchen is one of my fav cities: be back next year

All good points: it's just that I had not 'loaded' the wheel, it was at the straight-ahead when this happened.

I'll re-check the road surface but I drove it the very next AM and did not see anything that gave an indication of 'risk' as to traction.

[elh0102]

Couple of thoughts for the OP. Assuming you have some type of high performance summer tires, 40 degrees is cool, and you will definitely have less than the tire's warm weather grip. Of course, DSC doesn't know the temperature, and will intervene when its threshhold is reached. Regarding LSD, anytime the rear is totally loose, then LSD will contribute to the car's tendency to spin, since the inside rear tire is not acting as a rudder to keep you on course. It is great in its ability to get proper rotation started under throttle and, as long as you are maintaining some grip it will get you out of the turn faster. But once the car is beginning to come around, it only exacerbates your immediate challenge of getting the car back in shape; nothing wrong with it, just works that way.

There are comments that DSC may have malfunctioned. It could have, of course, but doubtful. One must remember, in order for DSC to maximize traction, it has to have some traction with which to work. Example, if the car is spinning on pure ice, there is nothing DSC can do with the throttle or brakes to regain traction, you're just gone. I think I heard one of the NASCAR drivers state the best cause for things like this.....shit happens, in technical terms.

[bigjae1976]

Originally Posted by Voltigeur

Answers:

* temp was about 40F
* no frost
* good quality of surface: even, tarmac in good condition, no potholes [having driven all 'round the world this road was top 10% condition]
* no leaves - TX - not such an issue where I live

Thanks for your input and all good qns but still mystified: have driven my car in much more tricky conditions and - aside from correctable slip - nothing like this has ever happened in 2 yrs of driving [28k mi - Germany and US].

I'm convinced that the cold weather and PS2s contributed to your sideways adventures. If something broke, I think it would have ended up much worse.

Even if it wasn't wet, the dust here in TX will make dry roads very slippery.

On my E46 330, I have a limited slip. I will say that the rear on the M3 is a lot more lively in comparison. You can get sideways quick in this car if you aren't at speed. At the track, you are putting a lot more force on the suspension so the car will be much more planted vrs coasting and minimal inputs on the street.

I don't think DSC malfunctioned at all in your case. It will not always save you. I dropped 2 wheels on the track went sideways and caught it...never felt DSC intervening.

[Voltigeur]

Originally Posted by elh0102

Couple of thoughts for the OP. Assuming you have some type of high performance summer tires, 40 degrees is cool, and you will definitely have less than the tire's warm weather grip. Of course, DSC doesn't know the temperature, and will intervene when its threshhold is reached. Regarding LSD, anytime the rear is totally loose, then LSD will contribute to the car's tendency to spin, since the inside rear tire is not acting as a rudder to keep you on course. It is great in its ability to get proper rotation started under throttle and, as long as you are maintaining some grip it will get you out of the turn faster. Buy once the car is beginning to come around, it only exacerbates your immediate challenge of getting the car back in shape; nothing wrong with it, just works that way.

Thanks elh - I think this is a reasoned analysis. Note, I had been driving for 40+ miles before this happened so tires were warmed up; & had sliced through a few corners and on hwy @ 70+ mph [the police do 80 here].

That being said I think the LSD must have exacerbated - perfect word - the loss of traction. I guess I am back to square 1 in wondering what caused the rear RHS to suddenly lose its friction - hence creating the rotation in the first - and FWIW I don't think DSC would have been a savior in this scenario as the movement was much more than normal.

In the end, goes to show you have to be alert and safety / traction aids are not a panacea. I respect the car, and glad my 'event' resolved itself w/ no harm done.

[Voltigeur]

Originally Posted by bigjae1976

At the track, you are putting a lot more force on the suspension so the car will be much more planted vrs coasting and minimal inputs on the street.

Fair pt.

[bruce.augenstein@comcast.]

Originally Posted by Voltigeur

Answers:

* temp was about 40F
* no frost
* good quality of surface: even, tarmac in good condition, no potholes [having driven all 'round the world this road was top 10% condition]
* no leaves - TX - not such an issue where I live...

40 degrees is almost certainly the culprit. Summer tires tend to go away, traction-wise, below 50 degrees F or so.

When I had my son's C63 tuned late last fall, driving home with 42 degrees showing it wouldn't stick until third gear. Come Spring and 70 degrees, no problem.

Bruce

[1sikbmr]

It happened to me aswell... Its cold outside so summer tires= death. Car ended up going sideways but i caught it back in time... Ripping it at bear mountain one last time.

[PhillyNate]

I'm not skilled enough to drive with DSC totally defeated. Not yet. The only way I could see myself doing that would be if there were nothing around to hit whatsoever. Having said that I've only executed MDM once in the Summer on the highway. I would never even use MDM in these current temperatures or lower. What's worse is these V8's get more powerful the colder the temps get and when combined with summer tires this makes for a sideways ending. No thanks. "I'll take the safety aids for $400 Alex."

[immiketoo]

I did this once on a motorcycle. The result was much more exciting than yours. Cold tires will kill you every time.

[Voltigeur]

Originally Posted by immiketoo

I did this once on a motorcycle. The result was much more exciting than yours. Cold tires will kill you every time.

On a 'cycle! My tires were warm after 40+ miles of vigorous driving.

[Voltigeur]

Originally Posted by bruce.augenstein@comcast.

40 degrees is almost certainly the culprit. Summer tires tend to go away, traction-wise, below 50 degrees F or so.

Tires were well and truly warm: 40 miles; prior cornering; 70+ on hwy. C63 has an amazing - amazing - engine - but know to be a handful given all that torque.

[immiketoo]

Originally Posted by Voltigeur

On a 'cycle! My tires were warm after 40+ miles of vigorous driving.

Yeah that one cost me a bunch of cash. And a bruised ego.

[DBH]

Originally Posted by Voltigeur

Tires were well and truly warm: 40 miles; prior cornering; 70+ on hwy. C63 has an amazing - amazing - engine - but know to be a handful given all that torque.

Sorry, no good...summer tires go away when the temp gets to around 40 degrees. I went out for a ride today, beautiful day - not a cloud in the sky and no wind. Temp was 38 degrees. Did about 25 miles, just crusin'. Came out of a 90 degree turn and gave it a little gas as usual...the back end started to come around. This has only happened a couple of times before. You guessed it, only when on summer tires when the temp is 40 or below. Winter tires go on this week!

[Voltigeur]

Originally Posted by DBH

Sorry, no good...summer tires go away when the temp gets to around 40 degrees. I went out for a ride today, beautiful day - not a cloud in the sky and no wind. Temp was 38 degrees. Did about 25 miles, just crusin'. Came out of a 90 degree turn and gave it a little gas as usual...the back end started to come around. This has only happened a couple of times before. You guessed it, only when on summer tires when the temp is 40 or below. Winter tires go no this week!

Sure: no debate "the back end starts to come around" [my emphasis].

This event was like a light switch being turned on: straight ahead then no wiggle, just very extreme oversteer And I have experienced oversteer in this M3 at lower temps, on back roads, w/ damp spots etc.

I guess I should have made that clear earlier: I have driven my car - MDM, no DSC etc - back roads = irregular surface], early morning in winter [colder than 40F] etc - and this lack of warning (e.g. more than usual slip) has never happened. Which is why I posted the original query.

[Voltigeur]

Originally Posted by username11

Stupid.

40 degrees and PS2 or CS3s = very limited traction especially in the rear. Why would you be driving around on public roads, temperature too cold for your summer tires, with DSC partially off (MDM)? This thread is evidence that what should have been the expected result was not expected. Missed Darwin award.

You may not have read the all prior posts [tires were not 'cold']. And if someone on this board thinks someone should die ["missed Darwin award"] from a mishap, then that speaks to something less than stupid. Good on ya mate!

[edit] I most certainly have done very some risky things is my life including sliding a car near a precipice in a 3rd world country - which I would not repeat under any circumstances. But this was not one of those times.

Shit happens: in this case, I was surprised by the 'shit' which motivated the post.

[Ateam]

[QUOTE=Voltigeur;10960528]You may not have read the all prior posts [tires were not 'cold']. And if someone on this board thinks someone should die ["missed Darwin award"] from a mishap, then that speaks to something less than stupid. Good on ya mate! [/QUOTE

You seem to lack basic reasoning and common sense.

You keep pointing out the "tires were not cold" There is nothing you can actually do to a summer tire to make them work below 40 degrees. You could smoke them for 30 minutes standing still and they still have no grip at 40 degrees. That is out of ones control and rather a property of the tires.

I agree people totally should know how to drive with no nannies engaged. But a public road is NOT the place to learn how to do so or test how well you do so, or even do so for no apparent reason.

What were you thinking you benefit from having MDM on in the city/streets? Only one reason people turn mdm on or dsc off, which is to allow more body rotation of the car or spin of the tires causing traction loss. Why would you need/want to do either of those in the city? If you are spinning your tires to go that fast or if traction on the ground is not good (such as you driving in 40 degrees with summer) you should be wanting dsc to cut in.

So there is nothing to "gain" by using mdm, or if there is please let us know in the middle of a city?

[Voltigeur]

Originally Posted by Ateam

I agree people totally should know how to drive with no nannies engaged. But a public road is NOT the place to learn how to do so or test how well you do so, or even do so for no apparent reason.

OK, but I was not in traffic. I accept the other point - and by no means was I trying hard. And I have driven this car much, much, harder on private [track] roads. So I fail to see your point on this. It's not an MDM issue; I said I pushed the throttle down sparingly - if one had DSC + 100% throttle and if conditions were poor the result would be far more dangerous.

Originally Posted by Ateam

What were you thinking you benefit from having MDM on in the city/streets?

So there is nothing to "gain" by using mdm, or if there is please let us know in the middle of a city?

I'm not in the middle of a city, in fact, I live in the country. This is assumed. MDM makes for a more responsive car and as I stated above, I don't habitually drive w/it engaged.

[Ateam]

Originally Posted by Voltigeur

OK, but I was not in traffic. I accept the other point - and by no means was I trying hard. And I have driven this car much, much, harder on private [track] roads. So I fail to see your point on this. It's not an MDM issue; I said I pushed the throttle down sparingly - if one had DSC + 100% throttle and if conditions were poor the result would be far more dangerous.



I'm not in the middle of a city, in fact, I live in the country. This is assumed. MDM makes for a more responsive car and as I stated above, I don't habitually drive w/it engaged.

See that is the part I am wondering, how does mdm make it a more "lively" car. It does not effect, throttle, engine, braking, suspension or anything other than letting more yaw changes without intervening. Just curious how this brings more fun? (honestly am asking you and curiosu

[El_Duderino]

Originally Posted by Ateam

You keep pointing out the "tires were not cold" There is nothing you can actually do to a summer tire to make them work below 40 degrees. You could smoke them for 30 minutes standing still and they still have no grip at 40 degrees. That is out of ones control and rather a property of the tires.

+1
I apologize if I have misinterpreted the OP's previous posts, but your summer tires will NOT grip at 40F, regardless of how many miles you've driven on them prior to the oversteer incident occurring. This is a property of the rubber used in summer performance tires and no amount of warming up the tires will change their tendency to lose traction in cooler weather.

IMO, there's nothing overly complex or mysterious about this situation. Inappropriate tires given the outside weather > loss of traction > snap oversteer. End of story.