Quote:
Originally Posted by tranquility
Our Z4s are made to start and go, maybe 1 min tops to get the fluids going. Idling that long is a no-no.
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Maybe not only our Z4s. My E60 M5 manual specifically pointed out that the car should not be idled for extended periods - maybe 30 seconds after a cold start but then warm everything up by modest driving which gets not only the engine but the gearbox and differential warm together. I also remember reading that some BMW engines would get excessive carbon build up in the heads if idled for long periods.
And maybe more on point with this discussion - to the extent that Efficient Dynamics are implemented on a Z4, battery charging is done largely through regenerative braking (the alternator is asked for maximum output during braking) and at idle either doesn't charge, or only minimally charges if the battery is getting low. It's very possible that the battery would be low after an extended period of time at idle simply because the alternator really isn't charging it.