DSC Effects on Mileage

[jotapeh]

Just curious if anyone knows whether or not turning off DSC completely (so you get the spinny triangle thing) would have an adverse effect on mileage? I'm talking normal driving conditions here, mostly highway.

I'm aware that any effect is likely minimal, but... Thoughts?

[Gray135i]

No, there is no effect on your gas mileage or your service interval mileage. I typically drive with the DSC completely off and have noticed no difference.

[david @ eas]

Nope no difference in gas mileage at all... I've compared the two on my e46 before and there wasn't any difference.

[jeremyc74]

I'm not sure why it would possibly make any difference. It doesn't do anything unless you're losing traction for some reason.

[jotapeh]

Originally Posted by jeremyc74

I'm not sure why it would possibly make any difference. It doesn't do anything unless you're losing traction for some reason.

I was interested mainly for two reasons:

1) If you consistently drive on slippery/dirty surfaces with DSC completely off, you may be over-revving the engine on a regular basis (even if only slightly) ie., decreasing MPG. BMW claims that their system kicks in 'within milliseconds, before the driver can even notice that something has happened' so this would be very possibly undetected by the unaided human driver and might even occur on surfaces that we would consider as having adequate traction.

2) Running with DSC on must drain some portion of battery power to run the computer/auto brakes, this might cause DSC to consume more energy than necessary -- but might be completely compensated for by regenerative braking?

There may be other factors involved as well that I haven't thought of. Anyway, it sounds like the consensus is that it has no effect on regular driving, and that's all I really wanted to know

[jeremyc74]

Originally Posted by jotapeh

I was interested mainly for two reasons:

1) If you consistently drive on slippery/dirty surfaces with DSC completely off, you may be over-revving the engine on a regular basis (even if only slightly) ie., decreasing MPG. BMW claims that their system kicks in 'within milliseconds, before the driver can even notice that something has happened' so this would be very possibly undetected by the unaided human driver and might even occur on surfaces that we would consider as having adequate traction.

2) Running with DSC on must drain some portion of battery power to run the computer/auto brakes, this might cause DSC to consume more energy than necessary -- but might be completely compensated for by regenerative braking?

There may be other factors involved as well that I haven't thought of. Anyway, it sounds like the consensus is that it has no effect on regular driving, and that's all I really wanted to know

Even on wet surfaces DSC is completely idle 99% of the time. It reacts very quickly, but it takes more than just a slightly slippery road to cause it to kick in. You're really not going to notice the difference driving around without it until you get on the gas pretty hard.

Turning the DSC off isn't going to save any energy. The processing is still happening, and it's a minute amount of energy in a car. You'd never be able to measure the difference. Even large current draws such as headlights don't make a measureable difference in mileage.


Also, these cars aren't using regenerative braking. There was some talk about that early on, but no one can confirm the US cars actually do it. It wasn't really regen braking anyway, just charging at the optimal times.

Not that I'm telling you whether or not you should leave DSC on or off, just that there's no reason it would effect fuel economy either way.