ccieurzo

I may be imagining things, but I noticed that once I set the TPMS to my snow tires (235/45-17), the DSC isn't lighting up nearly as much. Before I reset it, the DSC lit up and significantly reduced power even in 6th gear straight line accelleration. Now I can pin the throttle in 5th and 6th gear and it only occassionally flickers. Does the TPMS somehow tell the car to adjust for a different rolling radius? There is about a 1.5% difference between stock rolling radius and the recommended snow tire size.

Anita

I was hoping one of the board experts would answer your post so right now you're stuck with me There's still hope though!

Only based on my experience with my three M cars, there doesn't seem to be connection between the two, but again, I could be wrong.

I've run 17" wheels and snows on my '02 M5 and notice that with the DSC on, the snows brake loose and engage the DSC more on dry road surfaces, then my summer tires would.

I drive with the DSC off in the snow almost all the time--for me, it's a bit too intrusive--plus driving w/o in a safe location I think is good experience in knowing where your car's going to break loose, etc. BUT that's only me. You should only do this if you are comfortable doing so. Most people like the DSC on, it seems.

Anita

__________________
"When will I know that I really can't go
To the well once more time to decide on
When it's killing me, when will I really see
All that I need to look inside
Come to believe that I better not leave
Before I get my chance to ride" RHCP "Snow"

E55AMG2

The TPMS does not have any pressure sensors (hence, why you cannot see the pressure anywhere in the OBC) on the E39, rather it does indeed measure the individual wheel speeds. When you set your cold tire pressure and then put the system into setup mode, it records how many revolutions the wheels travel over a 10 min (i dunno if there is a set distance, I guess they did it this way so it can take an average and correct for there being turns in your route) period. BTW, this is in the manual.

FredW

Interesting. I'm running 18" wheels with my snows and they also break loose more than the OEM's I'm running in the other three seasons. It kind of surprised me. I'm keeping the DSC on 'cuz I'm not that good.

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That's my opinion, although I might not agree with it.

2001 M5, Titanium Silver, Black, Stock.(sold)
2005 Audi S4 Cabriolet, Moros Blue, Light Grey Interior
2003 X5 3.0, Grey Green Metalic
1994 B757-200
2001 B757-300
1999 B767-200ER
2002 B767-400ER

KBK

My take on DSC in winter:

The good- It saves your butt when the car breaks loose in all four corners, or when conditions are too slippery for decent accelleration. This will allow you to get somewhere fast..and will also save your butt in a corner where the conditions have changed, by shifting the amount of torque and HP applied to the rears. When the back lets go completely and you are on the verge of loosing it completely..it might save you and the car. So far, it's done this twice for me, both times on black ice. If it had not been on..on the one situation, at the least..I would not be on this board and typing this right now. It also holds back the S62's ability to easily and incredibly quickly spin those rear wheels up to a very high rpm. Without the DSC on, you can end up facing the other direction VERY easily. It helps you handle some extremely variable road conditions.

The Bad- It leads to careless and mindless acceleration and speed, without a full understanding of the sheer mass of this vehicle. Remember..with a tank of gas and you in it, it is over a full two tons of weight. The easy, controlled accelleration...can be followed by a very suprising inability to stop. You could be completely unaware of the true condition of the winter road in front of you and when the car is simply moving too fast..there isn't anything the car can do to save your butt, it's all on you..and that might come completely out of the blue.

Driving without the DSC on, keeps one VERY honest and in a state of full understanding of what the road conditions actually are. BUT..one must be a good driver and constantly remember and take into consideration the amount of weight the car has, combined with the horsepower and rorque of that engine..specifically how easily the RPM on the S62 engine can get to be very high and very fast.

I'm personally of two minds on this. The DCS is nice and all, but I like (hell no, LOVE) to drive my cars, not be driven by a computer...that's why I have a M5, not an M-B AMG.

The horsepower takes some getting used to. I should easily remember the very numerous times I 'snowbanked' 2ton+ 70's sedans up in Nothern ontario, as a teenager..if I switched to having the DSC off, instead of having it on, as I do now. Sedate driving is not an option, with the DSC off, though. You must stay on line and be actually driving the car..always. Always. Not one second away from being a thinking driver. For it is the one second of mindless winter driving that takes you and/or the car 'out'. This holds true with any winter driving, but doubly so with the DSC off.

Then, there is the issue of how the DSC istself is actually actuated. Does it damage the car???? See the thread on 'MAF issues' that I started. It has a bit in it, on the effects of traction control on engines and the associated isses that may occur in the whole engine/exhaust system, in terms of potential damage.

A suprisingly large part of the issues seen (speculated upon) with these M5's are also seen as being the detrimental parts of traction control, depending on how the traction control is achieved in the given vehicle. It is a very eye opening article.

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E55AMG2

The old E55's traction control is much less intrusive than DSC, but the car is less fun cause of the automatic

ccieurzo

Thanks for the input everyone. One clarification I should make is that I do expect that traction under accelleration is going to be worse with the snows. I think that the DSC computer does look at wheel RPMs to calculate slippage, and was more intrusive until I reset the TPMS. Accelleration on the same section of road in the same gear provoked a lot less ******ation and DSC flickering after the reset. I was looking to see if anyone has enough knowledge of the system to say yes or no.

After the snowstorm we had here last week, I keep the DSC on unless I need to rock the car out of the snow. I am convinced it saved my bacon a couple of times.

Anita

Please see the quote below---I think this may be why you needed DSC as a teenager-kidding kidding

And I will read your MAF post-thanks!!

Anita

__________________
"When will I know that I really can't go
To the well once more time to decide on
When it's killing me, when will I really see
All that I need to look inside
Come to believe that I better not leave
Before I get my chance to ride" RHCP "Snow"

J Irwan

Me too, I also have 18" winter setup, but thats just because snowtires has much less grip even on dry road condition compared to the summer tires... hence it will break loose a lot easier.


I always leave DSC on, especially in winter.
We just had our 8" of snow storm last week. And I have to carefully control my right foot to slowly accelerate especially from a deadstop...
(I shift on 2nd gear at 1300 rpm, just to avoid too much wheel spin from a deadstop )



Regardz,

J Irwan

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02 Carbon Black ///M5