Loaner car 2012 528i

I was given a 2012 528i loaner car by the dealer while my 335d was with them.
It was interesting that when I stopped at a traffic light, the engine sort of automatically
shuts off where the engine rpm is at 0. A/C would still be working and as soon as
I release my foot off the brake, it immediately starts right up and good to go.
BMW calls it efficient dynamics?? or something like that.

The engine will also turn back on if you begin to turn the wheel. The computer effectively sense that you intend to move and fires the engine up again. The engine has to get up to speed and warm up before this function will work, and you can bypass it by choosing a different mode such as sport or comfort.

I was given a stat by a dealer that you save gas shutting off the motor for any stop you expect to last 15 seconds or more (and that number isn't verified). The point is, many of us grew up with older cars where the wisdom said turning off the engine may save gas, but was harder on the starter and other components. Technology has changed and that is, reportedly, no longer the case.

I've talked to a few people who have the auto shut-off function on their cars and they weren't fans. I think I could grow to like it, especially when the MPG climbs to the high 30s.

Yes, I saw that. Just freaked me out when the engine rpm went to 0.
I think it is a neat techology and I would not mind having it as it will
not waste fuel.

Have to check the 2012, but EPA fuel economy ratings for 2011:
528i 6-cyl auto: 22/32 mpg
328i 6-cyl auto: 18/28 mpg

I had a 528i loaner and experienced this gas saving measure, too. I might like it if the car actually shut down smooth. But when it happens, it feels like you 1972 Buick just staled as it quivers to shut down. Now, I would expect that this feature would (a) put a lot of stress on the starter motor and engine and (b) would leave you in a very bad situation in an intersection when you need to punch the gas and floor it/to get out of the way. I will take the couple mpg fuel hit and escape with my life - thank you very much. If you can afford the Beamer, then just open your wallet and pay for the gas. NOT a fan, as if you can't tell.

Sent from my DROID Pro using Bimmer App

I didn't like the auto-shutdown either because it CLUNKED to a stop and then CLUNKED while starting up again and wasn't smooth or seamless or luxurious feeling at all. I'm guessing it's because it's a 4-cylinder with balance and vibration issues. Guessing the I-6 with start-stop might be better but haven't driven one. BTW the start-stop is NOT factored into EPA fuel mileage ratings.

Drove a loaner F30 while our E90 was at the dealer. This auto **** off felt violent, and it's got to impact the engine long term. I view it as another layer of complexity on a vehicle that is already laden with electronic gizmos, sensors, etc. I bet whatever little money this feature saves will be collected, and more, to maintain the system by BMW. I said it before and I'll say it again, couldn't wait to get our car back that day.

The 6 cyl turns on and off smoother, but its still noticable. I didnt like the start and stop at frist but have since gotten use to it. Now I actually like to sit in at red light with no engine noise or vibration. There is a button to shut off the start stop function and it can also be shut off by shifting into the sport mode or by turning the steering wheel.

The auto stop and start on F30 is not smooth. Much cheaper brands are better at this. BTW, this is not necessarily to save fuel, rather to lower emission. Like the above post said, EPA does not take it into consideration when measuring mpg.