Just after a quick shift from from 1st to 2nd gear, I experienced what I would consider a "throttle shut-down". The engine power was interrupted. Throttle position was approx. 1/2 way and RPM was around 2500.
With 2nd gear fully engaged (clutch long out by now) I got a DSC warning, but, time-wise, it actually illuminated AFTER the power-loss condition). I continued to hold the accelerator at position, until the engine kicked back in. It probably only lasted fractions of a second, but it seemed like an eternity to me.
Now, maybe this is the infamous "bunny hopping" which has been discussed previously, or, maybe this is DSC "working as designed", but this bothers me...
Kinda reminds of a documentary I saw about the "fly-by-wire" flight control on some commercial airliners. In certain (extreme) conditions, pilots often struggle with the flight controls saying: "How do I get this thing to ?".
I'll try running the car more with the DSC off...but if this repeats, I don't know what I'll do!? Agghh!
What ever happened to to good ol' throttle cable? ;-)
It is the DSC doing what it is supposed to. Turn it off and it won't happen. The rear tires will break loose, the car may fishtail and there will be some hellish acceleration, but no throttle cutting out.
Alright... Initially, I thought that DSC only had control of the brakes on each wheel. I did some more reading and, as I understand it now, DSC can actually can cut-back the throttle under certain conditions.
With the Sport setting "On" the throttle response on the M5 is faster than a "good ol' throttle cable". If you want to spin your wheels turn the DSC off.
Russ - yes, DSC affects engine power FIRST - then adds brakes. More impressively, it can brake individual wheels. If the pavement you're on provides traction on both sides, then when DSC comes as the car starts to spin, it will actually brake a front corner and the opposite side rear wheel.
Interesting sidenote: According to the teachers in Spartanburg, even the engine power is managed in two steps - first power is reduced by changing the timing, then by reducing throttle. (I'm personally a bit skeptical about this - why wouldn't throttle reduction alone be simple and effective?)
[This message has been edited by greg (edited 26 October 2000).]
With the Sport setting "On" the throttle response on the M5 is faster than a "good ol' throttle cable". If you want to spin your wheels turn the DSC off.
John
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C43///m5
'00 M5 Alpine White
'00 C43 Also White
"I'll try running the car more with the DSC off...but if this repeats, I don't know what I'll do!? Agghh!"
Russ. I highly dont recomend taking DSC off for long periods of time. I remember back last year when i took it off to have a bit of fun and just left it off. It was slightly damp and I was waiting to get an empty stretch of road so I could do some slalom runs back & forth in the lanes. Well the back end came out and I overcorrected a bit which put me in a tankslapper. It went back & forth about 4 times before I stopped, in the wrong lane. DSC, (in my case, ASC 97 328i sport) I would not have done that. So, all I'm saying is to leave it on unless you want to have some fun, when youre done, put it back on, you never know when you'll need it.
Well, I'm getting used to the car little by little (just over 800 miles on it now! :-) ). Last night I did some running around town with the DSC off... The 1st-2nd action is a bit more familiar to me... Got more tire spin and there was no "throttle shut-down".
It makes sense that the DSC system has tie-ins into the engine power... If it didn't, there'd be tremendous coil-up in the drive-line if you punched it and the rear brakes came on! Wouldn't want to damage the clutch, transmission, etc, now would we? ;-) It’s great what a better understanding can do...
...and, oh, for the most part, I think I'll leave DSC on... (except for those extreme conditions that warrant putting down a little more rubber onto the pavement!) 8D
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