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Traction control woes

7K views 22 replies 8 participants last post by  FT 
#1 · (Edited)
Ah, I hate the way traction control works in this car. It is the most aggressive system I have ever seen. It is constantly cutting power all the time! I just got owned by a crappy S4 because DSC was flashing like a christmas tree. I mean at first I was like "oh yeah, car is so powerful that's why", but my M5 never did it any of this. DSC on that car would only kick in if I were going WOT in 1st gear. That car has much more power and torque than the M3, so i dont get it.

I want to clarify, its 2nd to 3rd I am complaining about. 1st gear is utterly useless, but I wouldnt complain as much if 2nd gear worked fine.

Yes you can turn the traction control off, but I am never going to do that in public roads. MDM makes no difference in straightline acceleration scenarios, it allows more slip on drifting.

My take is, BMW made the DSC so aggressive to give room for improvement in competition package. I wish there was a way to tweak the parameters using an aftermarket tune.

By the way, launch control is almost always smokey burnout, but thats going to have its own thread.
 
#3 ·
I had an M5 before this, which was much more of a car than this M3 and never had an issue.

It has got nothing to do with the car being too much. It is bad engineering and software tuning. Same thing could happen in a 128.

I would never turn the traction control off in traffic.
 
#7 ·
I had an M5 before this, which was much more of a car than this M3 and never had an issue.

It has got nothing to do with the car being too much. It is bad engineering and software tuning. Same thing could happen in a 128.

I would never turn the traction control off in traffic.
Really?! I drive with the DSC off 99% of the time. Drive that Bitch like you stole it and don't let any Audi beat you again, otherwise we will repossess your BMW. :bigpimp:
 
#15 ·
Traction

I'm gonna seem like I'm trolling here, but I'm really not.

I had an E90 335, now I drive a "crappy" S4. I've always wanted an M car and I'm considering replacing the S4 with the F80 M3. This thread makes me think twice though.

The cons of the S4 are it's heavier than the M3 and under steers. But it's hard to beat the AWD and torque vectoring sports diff when the roads are wet more than half the year hear in the pacific northwest. The S4 is a really great daily driver. It seems like the F80 M3 does have the potential to suffer from a lot of low RPM torque that would be hard to take advantage of if traction is at all limited by wet roads etc.

I don't want a track car, just a fun performance oriented sedan that will keep my commute spirited when I want it to be.
 
#17 ·
I'm gonna seem like I'm trolling here, but I'm really not.

I had an E90 335, now I drive a "crappy" S4. I've always wanted an M car and I'm considering replacing the S4 with the F80 M3. This thread makes me think twice though.

The cons of the S4 are it's heavier than the M3 and under steers. But it's hard to beat the AWD and torque vectoring sports diff when the roads are wet more than half the year hear in the pacific northwest. The S4 is a really great daily driver. It seems like the F80 M3 does have the potential to suffer from a lot of low RPM torque that would be hard to take advantage of if traction is at all limited by wet roads etc.

I don't want a track car, just a fun performance oriented sedan that will keep my commute spirited when I want it to be.
I can understand your reticence being where you are but same old adage, don't rely on hearsay and try to get hold of a test drive (preferably on a wet day which may not be so hard up there:D) and see for yourself. Best of luck in your choice and hoping you will be pleasantly surprised by the M4 :)
 
#18 ·
The RWD car is so much fun, I mean to be able to slide the rear just a tad enough to have fun and that excitement, pretty much anywhere you want, is priceless. The problem is, as the previous poster said, there is just too much torque down low for this car for it to be able to put it down effectively. The chassis is too light, rear of the car is possibly too light (52/48) to deal with that kind of torque. We all know that this car does 500 or so tq in real life, not 406, and believe it or not, that's actually more torque per pound than the M5 (with dyno corrected).

I am not saying that torque is bad, it's quite handy in 3rd gear pulls for example. But what I'm saying is BMW should have made the DSC tuning just a bit aggressive so that it allows some sort of wheel spin unless the rear diff is getting locked. In other words, if you are accelerating in a straight line, DSC shouldn't be as aggressive as it is now. It is just to intrusive. Yeah sure I can man up and turn the traction control off, but there are times when you have your family with the car, you are accelerating in a 3 lane traffic with cars around you, it's not really the most sound thing to do.
 
#21 ·
MDM makes a difference on disproportional tire lock ratios, i.e while drifting/sliding. It makes no difference in straight line acceleration.

Anyways, I was actually going to say that I have had very good successful 9 total runs today with absolutely no DSC coming on and cutting me off. The difference was my tires were all over 110F. It was the same road, so I'm not sure if 15-20F of tire temperature can explain the drastic improvement.

That being said, again, this was not the case in my M5. I know the PSS tires in the M3 has a special compound and are different than the ones in M5. I'm sure all of this for a good reason. Maybe the tires are more track oriented and dont overheat? I'm not sure.
 
#23 · (Edited)
First, I am glad you could resolve your issue.

Second, I am not sure I understand what you said below. A differential will lock up or loosen based on wheel speed difference and in the case of M diff it also computes the lock up based on other parameters. I think you are assuming that traction at each tire is equal during straight line accel, which most often is not. Although I have no clue as to how the diff works in conjunction with DSC, do you have any technical info regarding that relationship?

MDM makes a difference on disproportional tire lock ratios, i.e while drifting/sliding. It makes no difference in straight line acceleration..
 
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