Auto Start/Stop - From hating it to totally loving it

[///M///]

So this is the first M that I have owned with the Auto Start/Stop Feature (previously E46 M3 and 2009 E90 M3). Here are the reasons I did not like it initially and honestly I don't have a good enough reason.

• New feature and I didn't bother to explore it
• Forum people bash it so it must suck
• Car switches off automatically and I feel I am not in control
• I have a performance car. Why do I need to save gas?
• My starter might go bad with so many start/stops
• This is probably too green for me

So over the last 6 full tank of gas cycles I decided to give it a shot alternating between using the Start/Stop feature and not using it. So I used it for a total of three tanks of gas and here are the results.

2016 F80 M3
6 Speed Manual

On an average my mpg increased by around 3 mpg and I did not change a thing in my driving habits. This meant that i could go 45-50 miles more on the same tank of gas.

And here is why I love it now.

• On the manual there is absolutely zero and I mean zero difference in how I operate the car with the Start/Stop feature enabled compared to how I would drive it with it disabled. My clutch is never engaged on red light stops and no matter how quick I think I am the car always starts and is ready to go way before I can release the clutch. So what's changed? Absolutely Nothing. I come to a stop at a red light, put the car in neutral and release the clutch, the car turns off. The light turns green and I press the clutch to put it in first and the car is already fired up and ready to go. I can try this as fast as I want a hundred times over but the car always beats me and the engine will always be ready way before I can release the clutch.
  
• I am not losing any performance by using this feature so why should I turn it off? If anything I am saving gas without changing a thing.
  
• I was very surprised at just how long I would be idling at red lights. When the car switches off the cabin is extremely quiet and it makes you to take notice and realize just how long it would have been running at that red light stop you just made. It all adds up to multiple minutes over a week
  
• The car is smart and realizes that if it's hot out and the temperature in the cabin is starting to rise, it will automatically start the car again to use the AC. No loss in comfort here.
  
• If you have your foot off the brake for some reason and start to roll forward or backward, the car is smart to detect that and instantly fires up the engine.
  
• I don't care if the starter is getting used more and could potentially fail earlier than a car that doesn't use this feature. I don't care because I will not be keeping the car beyond 4 years/50k miles so why worry?

So that pretty much sums it up. Most will still not try the feature but I have certainly come around to liking it

[brianeck]

All your other reasons are fine, but there is no way that the feature improves your mpg by 3 regardless of your driving habits. I would wager that there is another variable in play that you're missing here. Unless you are sitting for 15+ minutes at a time with the engine running I wouldn't think you'd notice an kind of significant change, as idling doesn't really even use all that much gas.

The purpose of the feature was actually to reduce emissions in traffic which it does, not to improve MPG. Its more of a trick to beat the efficiency tests then it is a real world gas saver. Saving gas would be better done by including a bigger 6th gear (or a 7th) and implementing on/off cylinders in efficient mode or 6/7th gear at highway speeds etc.

[brianeck]

Originally Posted by dsm918

So this is the first M that I have owned with the Auto Start/Stop Feature (previously E46 M3 and 2009 E90 M3). Here are the reasons I did not like it initially and honestly I don't have a good reason.

• New feature and I didn't bother to explore it
• Forum people bash it so it must suck
• Car switches off automatically and I feel I am not in control
• I have a performance car. Why do I need to save gas?
• My starter might go bad with so many start/stops
• This is probably too green for me

So over the last 6 full gas tank cycles I decided to give it a shot alternating between using the Start/Stop feature and not using it. So I used it for a total of three tanks of gas and here are the results.

2016 F80 M3
6 Speed Manual

On an average my mpg increased by 3 mpg and I did not change a thing in my driving habits. This meant that i could go 45-50 miles more on the same tank of gas.

And here is why I love it now.

• On the manual there is absolutely zero and I mean zero difference in how I operate the car with the Start/Stop feature enabled compared to how I would drive it with it disabled. My clutch is never engaged on red light stops and no matter how quick I think I am the car always starts and is ready to go way before I can release the clutch. So what's changed? Absolutely Nothing. I come to a stop at a red light, put the car in neutral and release the clutch, the car turns off. The light turns green and I press the clutch to put it in first and the car is already fired up and ready to go. I can try this as fast as I want a hundred times over and the engine will always be ready way before I can release the clutch.
  
• I am not losing any performance by using this feature so why should I turn it off? If anything I am saving gas without changing a thing.
  
• I was very surprised at just how long I would be idling at red lights. When the car switches off the cabin is extremely silent and it makes you to take notice realize just how long it would have been running at that red light stop you just made.
  
• The car is smart and realizes that if it's hot out and the temperature in the cabin is starting to rise, it will automatically start the car again to use the AC. No loss in comfort here.
  
• If you have your foot off the brake for some reason and start to roll forward or backward, the car is smart to detect that and instantly fires up the engine.
  
• I don't care if the starter is getting used more and could potentially fail earlier than a car that doesn't use this feature. I don't care because I will not be keeping the car beyond 4 years/50k miles so why worry?

So that pretty much sums it up. Most will still not try the feature but I have certainly come around to liking it

All your other reasons are fine, but there is no way that the feature improves your mpg by 3 regardless of your driving habits. I would wager that there is another variable in play that you're missing here. Unless you are sitting for 15+ minutes at a time with the engine running I wouldn't think you'd notice an kind of significant change, as idling doesn't really even use all that much gas.

The purpose of the feature was actually to reduce emissions in traffic which it does, not to improve MPG. Its more of a trick to beat the efficiency tests then it is a real world gas saver. Saving gas would be better done by including a bigger 6th gear (or a 7th) and implementing on/off cylinders in efficient mode or 6/7th gear at highway speeds etc.
But if you like the feature for the other aforementioned reasons by all means keep using it! I'm all for having options and the different opinions that lead us to either adopt to their usage or not. . .

I for one can't stand blind spot monitors or frontal collision control and opt out of the tech package for that reason on all my new cars. I don't like the yellow lights for blind spot I find them distracting, and the frontal collision warning actively braking for me almost got me in an accident on two occasions where I could have safely slowed down/maneuvered on my own until I was startled by the car's knee jerk brake reaction.

[///M///]

Originally Posted by brianeck

All your other reasons are fine, but there is no way that the feature improves your mpg by 3 regardless of your driving habits. I would wager that there is another variable in play that you're missing here. Unless you are sitting for 15+ minutes at a time with the engine running I wouldn't think you'd notice an kind of significant change, as idling doesn't really even use all that much gas.

The purpose of the feature was actually to reduce emissions in traffic which it does, not to improve MPG. Its more of a trick to beat the efficiency tests then it is a real world gas saver. Saving gas would be better done by including a bigger 6th gear (or a 7th) and implementing on/off cylinders in efficient mode or 6/7th gear at highway speeds etc.
But if you like the feature for the other aforementioned reasons by all means keep using it! I'm all for having options and the different opinions that lead us to either adopt to their usage or not. . .

I for one can't stand blind spot monitors or frontal collision control and opt out of the tech package for that reason on all my new cars. I don't like the yellow lights for blind spot I find them distracting, and the frontal collision warning actively braking for me almost got me in an accident on two occasions where I could have safely slowed down/maneuvered on my own until I was startled by the car's knee jerk brake reaction.

I was surprised as well. I am only reporting what I observed and this is another reason why I did it over three cycles of full gas tanks and took an average. I also alternated this with three cycles of full gas tanks of not using the feature. Results will vary depending on your commute. My commute typically involves 30 minutes of driving one way everyday to work with lots of traffic lights so obviously I am stopped a lot more than someone who mostly does highway driving. As for the consistency in driving style, it obviously can't be 100% consistent but I didn't consciously change anything in my driving habits. I wasn't out to set a record or prove anything to anyone. I was just curious so did this little experiment.

[Bluex]

Fascinating, and all very good reasons, Ricky.

I wish I could verify this as well, but as I have a DCT and am in Sequential mode 100% of the time, it's just impossible

I'm fairly certain my car would revolt if I put it in D long enough for Auto Stop/Start to kick in.....

[swagon]

I have nothing against ASS (heh). As long as I am able to turn it off by pressing a mechanical button.

I don't get the hate it gets on the Internet. Automatic blipshifts that cannot be easily disabled, those I see as a much bigger threat.

I automatically (sometimes even unconsciously) turn it off after starting the car. I use it only when:

1. engine is up to optimal temperatures
2. engine was running for a long(er) period of time
2. I was not beating on it before
3. I know that I'll be waiting at the traffic lights/railroad crossing/whatever for a longer period of time (don't know that every time, but you get the idea)

... so not that often.

I cringe every time someone stops at a crosswalk and engine shuts off for two seconds. And I highly doubt think there's any extra MPG you get with that.

And I get pretty angry every time someone leaves their loud TDI VW idling in the neighborhood.

Use your common sense, people, and the world will be a better place!

[///M///]

Originally Posted by Bluex

Fascinating, and all very good reasons, Ricky.

I wish I could verify this as well, but as I have a DCT and am in Sequential mode 100% of the time, it's just impossible

I'm fairly certain my car would revolt if I put it in D long enough for Auto Stop/Start to kick in.....

Yes I can see that but on the manual it makes zero difference because there is only one mode

[x.shell]

Originally Posted by swagon

I have nothing against ASS (heh). As long as I am able to turn it off by pressing a mechanical button.

I don't get the hate it gets on the Internet. Automatic blipshifts that cannot be easily disabled, those I see as a much bigger threat.

I automatically (sometimes even unconsciously) turn it off after starting the car. I use it only when:

1. engine is up to optimal temperatures
2. engine was running for a long(er) period of time
2. I was not beating on it before
3. I know that I'll be waiting at the traffic lights/railroad crossing/whatever for a longer period of time (don't know that every time, but you get the idea)

... so not that often.

I cringe every time someone stops at a crosswalk and engine shuts off for two seconds. And I highly doubt think there's any extra MPG you get with that.

And I get pretty angry every time someone leaves their loud TDI VW idling in the neighborhood.

Use your common sense, people, and the world will be a better place!

I think the reason why ASS gets so much hate is because of how BMW introduced it on the F chassis. Originally when it came out on the F30, it was always activated by default every time you started the car; their reasoning was to satisfy an EPA mpg test or some CAFE regulation. Everyone hates not having a choice.

After about a year of the F30 being out, the cries of the forum members reached BMW and they finally offered to code it to the current configuration for free. Now they all come with ASS configured to the last setting (like it should've been from the beginning), but the hate still remains.

[Dinh335]

I agree, it's much more tolerable in a manual cause of that extra level of control w the clutch...

i've had f30 w 6sp, and didn't mind it then, and now w my f80 i use it all the time and never mind it.

[mephiska]

Originally Posted by exo-shell

I think the reason why ASS gets so much hate is because of how BMW introduced it on the F chassis. Originally when it came out on the F30, it was always activated by default every time you started the car; their reasoning was to satisfy an EPA mpg test or some CAFE regulation. Everyone hates not having a choice.

After about a year of the F30 being out, the cries of the forum members reached BMW and they finally offered to code it to the current configuration for free. Now they all come with ASS configured to the last setting (like it should've been from the beginning), but the hate still remains.

There's also a ton of people who still think that ASS will cause premature wear on the starter, as if BMW (& Bosch actually) wouldn't have engineered the starter to accommodate the increased use cycles.

These are also the same people who think cars still have spark plug wires and distributor caps.

[AM4ZING]

extra 40-45 miles on a tank is totally worth it

It just gets annoying when approaching a stop and feels like the car stalls out

[ihg90]

I use ASS in my 2016 M4 DCT, but also control when it kicks in by how much pressure I put on the brake pedal - depressing it all the way initiates ASS, but just holding it down far enough so that the car doesn't move does not put the car into ASS - helpful for what I know will be a short stop...

[Sahbatage]

great write up.. you've convinced me to at least give it a shot now.. i had it turned off the second i left the dealership.. i have a MT too so i guess i don't have some of the same issues as a DCT would.

[DaBean]

THANK YOU!! Seems so wasteful not to use it, especially on the 6MT. On the DCT, I get it because it requires a change of habit (still...)

I actually drive in auto mode when I'm just putting around town to enable AS/S, which is a change from when I had my E46 M3 SMGII, in which the transmission never left manual mode. In the F8X, the auto is so smooth, and actually shifts better than I do (in part because the car is so quiet I forget to upshift), so it's a win/win/win when I'm in the city: smooth, better mileage, and less work.

[t0ny32]

It's a well designed system compared to the first generation. I use it occasionally too and i find it does help with fuel consumption in a stop and go environment. Also the technical term for the system is not ASS, it's MSA

[swagon]

Originally Posted by mephiska

There's also a ton of people who still think that ASS will cause premature wear on the starter, as if BMW (& Bosch actually) wouldn't have engineered the starter to accommodate the increased use cycles.

You're not doing the engine a favor by turning it off and on every time you stop, and do not forget the battery...

Originally Posted by exo-shell

I think the reason why ASS gets so much hate is because of how BMW introduced it on the F chassis. Originally when it came out on the F30, it was always activated by default every time you started the car; their reasoning was to satisfy an EPA mpg test or some CAFE regulation. Everyone hates not having a choice.

After about a year of the F30 being out, the cries of the forum members reached BMW and they finally offered to code it to the current configuration for free. Now they all come with ASS configured to the last setting (like it should've been from the beginning), but the hate still remains.

That's a US-only thing, though. In Europe and probably the rest of the world, ASS is activated by default every time you start the car.

ASS has been around since 2007 when they first introduced the N47 4-cylinder diesel engine in the E90 - 6MT 320d was, I believe, the first one to get the EfficientDynamics package which included the start-stop system.

[///M///]

Originally Posted by AM4ZING

extra 40-45 miles on a tank is totally worth it

It just gets annoying when approaching a stop and feels like the car stalls out

Only if you are rolling in neutral and it under 2 mph.

[mephiska]

Originally Posted by swagon

You're not doing the engine a favor by turning it off and on every time you stop, and do not forget the battery...

Again you're assuming they didn't engineer other components to account for this.

[swagon]

Originally Posted by mephiska

Again you're assuming the didn't engineer other components to account for this.

The battery will last more if you do not use ASS.

[///M///]

Originally Posted by swagon

The battery will last more if you do not use ASS.

True but how much longer? I think most on here care about the time the car is under warranty.

[swagon]

Originally Posted by dsm918

True but how much longer? I think most on here care about the time the car is under warranty.

Of course, they're enginereed to last 4 years/100-120k km and then they having problems.

I don't know; mine's still good after 8 years of daily use.

[mephiska]

Originally Posted by swagon

The battery will last more if you do not use ASS.

True, but I don't see how burning more fuel at stop lights wasting gas and increasing emissions just so I can get a few more months of life out of the battery is a good trade off.

We don't even know the typical lifespan of the Lithium batteries in our cars yet, so who's to say how much longer the thing will last by avoiding the stop/start feature.