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      12-08-2012, 02:03 AM   #22
hans007
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Drives: 2020 BMW M340i
Join Date: Aug 2012
Location: Los Angeles, CA

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Quote:
Originally Posted by RPM90 View Post
As you've discovered it won't shut the engine off under certain circumstances such as when the engine is still cold, as it needs to warm up as quickly as possible for emissions reduction. It won't shut the engine off if the ambient temperature is too hot, or it may restart the engine before you release the brake. It depends on how hot the outside air is. There is a gel in the air ducts that freezes/gets very cold while the AC is running so that when ASS shuts the engine off the air vents keep blowing across the gel to keep cool air coming into the cabin. If the car is still stopped and the gel has warmed, ASS may restart the engine to provide cooling.
If it's too cold outside the same things can happen, as vents will continue to blow warm air until it's exhausted, and if the car isn't moving the engine may restart to provide heat.

IIRC, if the trans is in "manual" mode, ASS won't activate.
ASS may also not activate if the driver mode is in sport+, but I'm not sure about that one.

Seems BMW spent some time working out the little details on implementing ASS.
The part they need to work on some more is with the AT. Once the car comes to a stop there is still load torque being applied to the RWD, and thus there is some compression of the front suspension. When ASS shuts the engine off there is no more torque on the drive line and you can feel the rear suspension drop down. It's an odd sensation.
I don't use ASS, not the BMW type at least.

the rear suspension drop down thing i havent really noticed. the only thing that is a little not luxury seeming is that when it starts up again, it is not exactly perfectly smooth.

i dont' know i live in LA. today is friday and i decided to leave work at 6pm (which was earlier than i usually leave) and attempt to make it to my apartment at a reasonable time. i took surface streets and it took 35 min. (the distance was a total of 5.5 miles, and people wonder why no one buys a manual here...)

anyhow, you could easily see how much fuel automatic stop start saves in those conditions. I think its a great technology honestly and plan to use it. I still think its stupid they coded it to not save by default, but yeah there are all sorts of conditions for when it wont do it. it actually flashes a little auto stop start circle crossed out on the dash, when it would have used it but wont use it due to say the engine not being warm yet etc.
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