Auto Stop-Start: Enable/Disable?

I don't own a car with a stop/start system myself, but personally I don't like it - it would irritate me. Debates over fuel savings and wear and tear issues aside, if I ever buy a car with it, I would keep it off permanently.

While we are on the subject, I was wondering - how does such a system work with the launch control function of many performance vehicles on the road today? I guess you would have to turn it off before engaging launch control? Also, I understand that it switches on quite fast, but if you want to "robot race" the guy next to you, without using launch control, don't you still lose out a little?
 
bluepoole said:
While we are on the subject, I was wondering - how does such a system work with the launch control function of many performance vehicles on the road today? I guess you would have to turn it off before engaging launch control? Also, I understand that it switches on quite fast, but if you want to "robot race" the guy next to you, without using launch control, don't you still lose out a little?
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I believe that if you flip a BMW into Sport mode, it automatically disables auto stop/start temporarily for this very reason. I wouldn't recommend robot races in Eco Pro or Comfort modes, lol.
 
Archer said:
Would it bother you if you felt that excessive idling was placing undue stress (and therefore wear and tear) on your engine?
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Yes obviously, which is why I'd use the system at my discretion as the driver. It's a trade-off, isn't it? One needs to try to judge how long one will be stopped for and whether it will be better for the engine to be off or for it to be on (exact same situation as in a car without SS). Auto Stop/Start doesn't have eyes and so it just turns off continually, even for shorter times than would possibly deliver any fuel savings. I believe that by combining a driver's intuition with SS that is off by default, you can get the best of both worlds. As previously mentioned, due to CAFE and other legislation, BMW was incentivised to keep the system on by default, but that doesn't mean it's the best for the car or the driver.
 
Foxhound5366 said:
I believe that if you flip a BMW into Sport mode, it automatically disables auto stop/start temporarily for this very reason. I wouldn't recommend robot races in Eco Pro or Comfort modes, lol.
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Yep Sport mode takes SS off and I think you can only launch in Sport Plus.
 
[video=youtube;k159M8QhCIE]https://www.youtube.com/watch?v=k159M8QhCIE[/video]
 
Drifter said:
[video=youtube;k159M8QhCIE]https://www.youtube.com/watch?v=k159M8QhCIE[/video]
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Nice comprehensive video! So there is no real benefit in fuel consumption, quite a degradation in ride sophistication, and probably not (but even he says maybe) additional wear-and-tear.

I'll keep playing it by ear, literally, as I get used to all the car's unique ways of doing things :)

If anybody finds more factual info/studies on this topic, let's resurrect the thread in the future to share that.
 
dlk001 said:
Is there proof? What is the probability of engine failure?
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I don't think anybody thinks total engine failure will result, and unfortunately none of us will ever see the true OEM analysis into their failure rates and workshop jobs after warranties have expired.

If anybody does get a source of that info, please do share it :)
 
Foxhound5366 said:
Sauron, do you personally drive with auto stop/start always enabled on your car?

Also, like that story I quoted points out, any time a car is switched off you get a boundary condition where metal rests against metal and has to overcome this friction during start-up. Whether the enhanced oils manage to provide sufficient lubrication to fully overcome the increased friction from 10x the number of start-ups is the entire discussion.

Regarding the point made about wear-and-tear from stop/go traffic, I'm not advocating permanently disabling SS. I am personally going to ask my dealer to at least let my car remember my last SS setting so that it can default to off when I turn my car on, and then I can choose to turn the system on when I feel it would be helpful.

FiestaST, that's an interesting thread. The last post was particularly interesting, with the guy complaining about how there is a high-pitched sound whenever SS is activated and it disappears with SS deactivated. Is that an example of a SS-related failure? Unfortunately we don't get the end of the story lol.
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My current car doesn't have it but the next one certainly will and I have no intention of deactivating it.

Have driven a few with the feature and the modern implementation is almost transparent so it's not like it even bothers me while driving. Also haven't had any horror stories from owners of said cars.

There should never be a reason that metal rests against metal unless the car is brand new and being broken in. That's what piston rings and gaskets etc are for.

Otherwise you would have endless pieces of metal laying about in your sump which simply isn't the case after the initial service.

What about the inverse effect of wear and tear because the engine stays on and goes through heat cycles because it isn't moving? The net result should be much the same, except at the expense of fuel/environment.

You know this is almost like the argument that turbo's aren't reliable and all that jazz.

It's simply a non-issue.
 
Well Sauron, unlike a turbo, we the motorists are offered the decision of deactivating the SS system ;)

At the very least that raises the question over whether or not to push that button.

As for the rest of it, more experience and investigation will be needed.
 
Foxhound5366 said:
I don't think anybody thinks total engine failure will result, and unfortunately none of us will ever see the true OEM analysis into their failure rates and workshop jobs after warranties have expired.

If anybody does get a source of that info, please do share it :)
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That's why it doesn't bother me i.e. engine wear and tear. :). If it ever becomes an issue, it would be covered by the motorplan in my case.

I don't have any reason to hate the feature. I have two reasons to like it. i.e. fuel consumption and engine restart sound.
 
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dlk001 said:
That's why it doesn't bother me i.e. engine wear and tear. :). If it ever becomes an issue, it would be covered by the motorplan in my case.

I don't any reason to hate the feature. I have two reasons to like it. i.e. fuel consumption and engine restart sound.
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Lol, there's the benefit of being a new-car buyer :p Also with your sporty car, the engine startup is all part of the fun, whereas for other people it's seen to detract from the refinement. Just spare a thought for the rest of us regular folk, mkay? Let us worry about these things.
 
bluepoole said:
but if you want to "robot race" the guy next to you, without using launch control, don't you still lose out a little?
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On a BMW, as soon as you have intensions to race, you simply reduce pressure slightly off your brake pedal and the engine will restart. It actually requires less effort than switching to Sport Mode, Switching off traction control i.e. other steps required for a proper robot race. ;)
 
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Foxhound5366 said:
Lol, there's the benefit of being a new-car buyer :p Also with your sporty car, the engine startup is all part of the fun, whereas for other people it's seen to detract from the refinement. Just spare a thought for the rest of us regular folk, mkay? Let us worry about these things.
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:p maybe if I was driving a noisy diesel I would hate it.
 
Foxhound5366 said:
Nice comprehensive video!
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:rolleyes:
Just looking at the description:
"You can idle your engine all day long and it's still not going to cost you as much as a burger and fries"
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So a random google suggests idling requires 0.6l/h per litre of engine displacement, so in 24 hours thats 20l for a 1.4 engine, or ±R250... Must have some expensive burgers or really small cars where he is from :D
 
Archer said:
So a random google suggests idling requires 0.6l/h per litre of engine displacement, so in 24 hours thats 20l for a 1.4 engine, or ±R250... Must have some expensive burgers or really small cars where he is from :D
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In his video, to be fair, he doesn't say "all day long" ... I think he says one hour? It was a shorter period, however, and it did illustrate the point that stop start really is a pointless technology for shorter breaks.
 
Foxhound5366 said:
In his video, to be fair, he doesn't say "all day long" ... I think he says one hour? It was a shorter period, however, and it did illustrate the point that stop start really is a pointless technology for shorter breaks.
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Well then the be fair he should call it unmitigated bull**** in the description either :p
Except over a year, with a low estimate of 5 minutes idle each way to work and back, thats 33 hours of idling that could've been saved. Now all of a sudden it starts making lots of sense. And I'd expect it be me more like 10-15 minutes for people stuck in traffic for more than an hour. Heck, before I got a bike a part the last part of my commute (a 3km stretch) averaged 25 minutes... How much would I have saved there with stop/start
 
Archer said:
Well then the be fair he should call it unmitigated bull**** in the description either :p
Except over a year, with a low estimate of 5 minutes idle each way to work and back, thats 33 hours of idling that could've been saved. Now all of a sudden it starts making lots of sense. And I'd expect it be me more like 10-15 minutes for people stuck in traffic for more than an hour. Heck, before I got a bike a part the last part of my commute (a 3km stretch) averaged 25 minutes... How much would I have saved there with stop/start
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Aah well, that's how he gets quoted in forum threads in other countries. I think his basic point is still valid, and it's pretty much what I've been saying from the start: SS that is on by default is more about helping OEMs with their legislative requirements than about truly benefiting motorists' fuel economy and driving pleasure. Can we still make use of SS? Sure. As drivers do we need to be more in control of the systems (rather than them just being on by default regardless of your previous setting)? Definitely.
 
The Golf 7 I had had quite a nice SS system. You could come to a complete stop and hold the pedal down. Depressing it further though would activate the SS and stop the engine.

With the 320i you don't have that option when it's on. Coming to a stop turns the engine off so you learn to leave a gap in front of you and play with the brake pedal and keep inching forward. Eventually i got annoyed and turning it off became part of the start up process.

I only use SS at robots I know I'll wait more than a minute.
 
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