What's this Auto Start Stop Thing All About?

Does the engine really shut off and restart everytime you come to a stop? At that rate the starter won't last a year.

Originally Posted by bobkat09

Does the engine really shut off and restart everytime you come to a stop? At that rate the starter won't last a year.

It's been used on some BMW's in Europe for a few years now. It uses a special starter motor. It's well proven technology.

is deactivated when you are using sport +....not sure about just regular sport, but there is alos a button above the on/off button to deactivate it

More than just BMW is using it and not just in Europe. VW and Fiat introduced it in Europe in the '80s. Audi, Alfa Romero, and Citroën both use the technology. BMW started using it in 2008. It's being used in Japan by Toyota, Mazda, and Honda. I'm pretty sure that my friend's 2011 E90 M3 has it.

It's all about fuel efficiency and emissions. Manufacturers must meet ever increasing CAFE requirements and are pulling out all the stops to do whatever they can to reduce emissions and increase fuel efficiency.

On the F30 BMW's implementation includes a button under the start button that allows the driver to turn if off if they don't want to use it but it will be on by default.

The biggest problem with this technology is not the starter but the battery being discharged by having to restart the engine far more frequently.

Originally Posted by SD 335is

The biggest problem with this technology is not the starter but the battery being discharged by having to restart the engine far more frequently.

I don't understand why they couldn't use momentum to wind a spring that would turn the crankshaft to start the motor again when the time comes.

I had auto start/stop on the 535i I drove in Europe. I must admit at first it was a bit creepy having the car go dead silent at the lights, but I quickly got used to it and actually rather liked it. The car sprung to life pretty damned quickly as soon as you let off the brake and got ready to hit the gas pedal... but I will warn you that jackrabbit starts from the lights are a no-no. I got hung up once or twice by the car being half a heartbeat behind me when trying to get around a left turn at a set of lights... sometimes quite scary when a truck is heading right for you.

Now, having said that after 10 days in Europe I was well accustomed to it and found it nice and relaxing to have the car shut off if I was at the lights long enough. It does get around the battery discharge problem because if the battery is too discharged it won't shut the engine off. Similarly if you're sitting at the lights for a REALLY extended time then the engine will fire up periodically to keep the battery charged.

The only real downside I found was that in combination with ComfortAccess it can confuse you a little. Once at a rest stop in Northern Germany I returned to the car after a few minutes to find it running. I had neglected to hit the stop button when I got out, and while I had locked the car, when I got out I didn't think about the engine because I didn't hear it running. Because it wasn't running, of course. I laughed, but I couldn't help but be a bit creeped out by the idea that if I had stopped in a bad neighbourhood and not locked it, someone could easily have driven away with the car even without the key.

Originally Posted by thumper_330

Now, having said that after 10 days in Europe I was well accustomed to it and found it nice and relaxing to have the car shut off if I was at the lights long enough. It does get around the battery discharge problem because if the battery is too discharged it won't shut the engine off. Similarly if you're sitting at the lights for a REALLY extended time then the engine will fire up periodically to keep the battery charged.

This is what immediately came to mind when I first read about this technology being brought to the 3-series. BMW seems to have a problem keeping the battery charged with short trips. I can imagine this will extend the length of the trip necessary to keep the battery properly charged.

On the F10, it makes a whopping 1 MPG difference. Why bother?

Any fuel savings will be lost to premature component failure.

This reminds me of the V8-6-4 and converted gas to diesel engines that GM came out with in the 70's. The drivetrain was not designed for these kinds of features and they failed prematurely.

I am all for better fuel economy as long as it makes sense. But with modern BMWs constantly having battery drain issues, this makes no sense to me.

Originally Posted by thumper_330

The only real downside I found was that in combination with ComfortAccess it can confuse you a little. Once at a rest stop in Northern Germany I returned to the car after a few minutes to find it running. I had neglected to hit the stop button when I got out, and while I had locked the car, when I got out I didn't think about the engine because I didn't hear it running. Because it wasn't running, of course. I laughed, but I couldn't help but be a bit creeped out by the idea that if I had stopped in a bad neighbourhood and not locked it, someone could easily have driven away with the car even without the key.

But I thought that the gear shifter doesn't move when the key is not present, at least that is how it works on my car with comfort access.

^^Not if it's a manual.

Originally Posted by chuck92116

On the F10, it makes a whopping 1 MPG difference. Why bother?

Any fuel savings will be lost to premature component failure.

This reminds me of the V8-6-4 and converted gas to diesel engines that GM came out with in the 70's. The drivetrain was not designed for these kinds of features and they failed prematurely.

I am all for better fuel economy as long as it makes sense. But with modern BMWs constantly having battery drain issues, this makes no sense to me.

What "constant" battery drain issues are you referring to? I've certainly never had one in 50,000 miles.

Originally Posted by Michael Schott

What "constant" battery drain issues are you referring to? I've certainly never had one in 50,000 miles.

That comment about battery drain and component failure came from another planet.

Good day gents....so what about the AC. I'm here in central TX and in the summer being a minute with out AC and no cooled seats is going to SUCK big time

nobodies ass sweats more than mine, and i have never had an issue with bmw's dakota leather...the ac blows cold, and get your windows tinted

I have Dark Tint and Beige Dakota Leather, it get hot as bawls here. That picture is taken right after I got out of work in Aug. You want to sit at a god awful light that takes for ever with out AC?

damn...i cant even imagine 111

hottest mine has said is 104 maybe 105

Originally Posted by thumper_330

but I will warn you that jackrabbit starts from the lights are a no-no. I got hung up once or twice by the car being half a heartbeat behind me when trying to get around a left turn at a set of lights... sometimes quite scary when a truck is heading right for you.

How does this work with manual transmission cars? Does the car have to be in neutral? If so, I think it would work pretty well since one would be out of neutral when ready to go.

Originally Posted by esquilax

Good day gents....so what about the AC. I'm here in central TX and in the summer being a minute with out AC and no cooled seats is going to SUCK big time

Seems like nothing to worry about - during a Texas summer the thing will never shut off at a light based on this from the F10 forum: http://www.bimmerfest.com/forums/sho...6&postcount=11

The Auto Stop-Start doesn't kick in when:

1. Outside temp <3°C or >30°C with switched on A/C. <-- Thats <37°F or >86°C
2. Interior temperature not yet attained (i.e still heating up or cooling the cabin)
3. After driving in Reverse.
4. Battery is not fully charged
5. Engine not yet operationally warm.
6. Defrosting is in effect.
7. Stop & Go traffic
8. Engine bonnet/hood is unlatched.
9. HDC is activated
10. Large steering movement

Also, the driver can prevent the Stop-start function on a case-by-case basis. Immediately after the car is stopped but before the function cuts the engine, forcefully pulse/push the brake pedal to the floor then quickly release.

Originally Posted by mr_clueless

How does this work with manual transmission cars? Does the car have to be in neutral? If so, I think it would work pretty well since one would be out of neutral when ready to go.

Yes, neutral with clutch out. As soon as you depress the clutch the engine will start.

Originally Posted by pcbrew

Yes, neutral with clutch out. As soon as you depress the clutch the engine will start.

Originally Posted by pcbrew

Yes, neutral with clutch out. As soon as you depress the clutch the engine will start.

Maybe I'm the oddball, but I don't typically sit at a stop light with the clutch out and shifter in neutral. With my driving habits it looks like the car would rarely shut off.

Originally Posted by toph

Maybe I'm the oddball, but I don't typically sit at a stop light with the clutch out and shifter in neutral. With my driving habits it looks like the car would rarely shut off.

I'm the other way round so this would work for me. I have seen discussions on this topic as to what is the "right" way to stop at a traffic light in a manual transmission car. About the only advantage of staying in gear with the clutch depressed is that the car is ready to go as soon as the light turns green. Otherwise, it seems like there is no difference (with respect to for example, clutch wear). I also find it easier on the foot to get into neutral. The main disadvantage I have with my approach is that I sometimes "struggle" to get the car into gear because I don't pay attention to depressing the clutch all the way.

Originally Posted by toph

Maybe I'm the oddball, but I don't typically sit at a stop light with the clutch out and shifter in neutral. With my driving habits it looks like the car would rarely shut off.

Have you ever had a throwout bearing replaced? Your method supposedly accelerates wear on the throwout bearing. Something I was taught about 45 years ago. Google "throwout bearing failure".

It will exacerbate TO bearing failure in alot of cars, not so much in others. Largely due to TO bearing design - most last longer than the life of the clutch, so it's not even a concern, but I know in my Legacy GT the TO bearings have been known to fail early and tear apart the transmission input shaft.

Anyway, if stop/start works upon clutch pedal depression/gear selection, then I'm good to go with it. I shift into 1st gear a few seconds before I want to take off from a stop, so the engine will be back on and won't "slow me down".

I sit at long lights/stops in neutral. No reason to have my throwout bearing spinning when I can easily observe there's no where to go in the next few seconds.

I've never had a problem with TO bearings. I'm not opposed to changing the way I sit at traffic lights to gain the benefit of the auto stop/start. I suppose if my car had a heavy clutch, I wouldn't drive the way I do now.