DSC off + cruise control?

[mofomat]

I'm not sure if we are talking about two different things here, not helped by the fact that possibly things were different on European and US E46 M3's.

On my E46 M3, you would press the DSC button once, briefly, to disengage DSC. This would completely turn off traction control, but would still leave certain systems (which I can't remember as it's been a while) active. To completely disengage everything there was an unofficial feature whereby you could press and hold the DSC button to completely deactivate everything.

On the new M3, if you want partial deactivation of DSC, you have MDM (providing you have M Drive). I can't see why they would make DSC the same, and in fact I would imagine pressing DSC OFF would be one step further than MDM.

One clue here is that on the old M3 the button was just labeled 'DSC', where as on the E92 M3 it is specifically labeled 'DSC OFF'.

[mkoesel]

Originally Posted by mofomat

On my E46 M3, you would press the DSC button once, briefly, to disengage DSC. This would completely turn off traction control, but would still leave certain systems (which I can't remember as it's been a while) active. To completely disengage everything there was an unofficial feature whereby you could press and hold the DSC button to completely deactivate everything.

I remember reading this long ago too, but could never be sure if my car operates this way. All can say is that, if there is anything still active after the first button press, I can't figure out what it might be. That is, at least as far as traction-control is concerned. Once DSC is off, the car will easily break the tires loose and get sideways, so I can't imagine what more you would need to do to provoke a response from any remaining traction related systems that are still in effect.

As a corollary, I believe that my wife's old E46 325 did indeed have the two distinct modes for DSC (much like the E90 does today), and in fact would show a different dash light for each one (again, much like E90 does today).

On the new M3, if you want partial deactivation of DSC, you have MDM (providing you have M Drive). I can't see why they would make DSC the same, and in fact I would imagine pressing DSC OFF would be one step further than MDM.

Well, my understanding is that MDM does in fact kick in still durring tail wagging maneuvers. I believe that it is distinctly more intrusive than when you have DSC off in an E46 M3 or any current E9X car for that matter. I.e it will let the wheels spin fairly liberally, but not allow you to get too far sideways. Now I have no experience with MDM of course, I base my understanding only on what I have been able to glean from reading.

One clue here is that on the old M3 the button was just labeled 'DSC', where as on the E92 M3 it is specifically labeled 'DSC OFF'.

Not sure how much that really matter though since, like I say, pressing the DSC button on my M3 eliminates any possibility for throttle cut off as far as I can tell. I can only guess that the DSC off button on the new M3 will do the same, and that MDM will do something else that is substantially more intrusive.

[mofomat]

I've just remembered. If you turn DSC off in the E46 M3 you still have ABS at least.

MDM allows a certain level of freedom to get the back end out but will eventually reign you in.

DSC OFF will not cut the power at all.

[mkoesel]

Originally Posted by mofomat

I've just remembered. If you turn DSC off in the E46 M3 you still have ABS at least.

That does sound familiar. Don't think I've ever tried holding down the DSC button and then breaking very abruptly. Probably not something I would want to do on the street anyway as I do not find ABS to be too intrusive.

MDM allows a certain level of freedom to get the back end out but will eventually reign you in.

DSC OFF will not cut the power at all.

Righto. Now, I wonder if the E92 M3 will at least allow cruise while in MDM mode, if it won't while DSC is off completely? The normal 3 series will not allow cruise even in DTC mode (which is similar to the M3's MDM mode in that both of them are "partial nannies enabled" modes).