Auto StartStop

[Alex381]

But shouldn’t always stay started keep the battery charged?

The battery is beefed up to be able to handle all the ASS. It will still fail earlier from all the extra charge/discharge cycles, but it is a significantly better battery than you’d have otherwise.

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[Cz_Ziemniak]

The battery is beefed up to be able to handle all the ASS. It will still fail earlier from all the extra charge/discharge cycles, but it is a significantly better battery than you’d have otherwise.

I'd wager to bet that it doesn't discharge the battery nearly as much as you'd think.

 

[Zig]

The battery is beefed up to be able to handle all the ASS. It will still fail earlier from all the extra charge/discharge cycles, but it is a significantly better battery than you’d have otherwise.

Oddly never had as many battery issues than what is noticed with the incorporation of the malfunctioning always stay started function.

 

[DT-GT]

I don’t know how ASS truly impacts battery life vs all the electronics etc, but battery life in our cars does seem to be an issue.

As for the benefits of ASS, be it good or bad, I DON’T LIKE IT.

Oddly never had as many battery issues than what is noticed with the incorporation of the malfunctioning always stay started function.

 

[Gregs24]

Yep. Now add on disabling that crap and the engine will last even longer still while benefiting from all the enhancements needed to keep it from breaking things. The only component that will absolutely fail earlier from ASS is the battery.

Which is why cars with S/S usually have AGM batteries or uprated batteries which don't fail earlier (actually last longer)

Remember hybrids you cannot turn off S/S as that is how they work.

 

[DT-GT]

If I had wanted a hybrid I would have purchased one. If a SUV, then a SUV. If a truck, then a truck. I’m just saying that I DON’T LIKE IT IN MY MUSTANG.

Which is why cars with S/S have AGM batteries which don't fail earlier (actually last longer)

Remember hybrids you cannot turn off S/S as that is how they work.

 

[Gregs24]

I'd wager to bet that it doesn't discharge the battery nearly as much as you'd think.

Agree - a hot start is far easier than a cold start. Plus if there is an ISG or hybrid system then the 12v battery doesn't do it anyway

 

[Zig]

Which is why cars with S/S usually have AGM batteries or uprated batteries which don't fail earlier (actually last longer)

Remember hybrids you cannot turn off S/S as that is how they work.

Agm can be used in non s/s vehicles, in fact i put a red top in my ‘05 vette.

stop start doesn't actually stop the motor it simply puts the engine to sleep. The electric motor is still active for action even when the engine is stopped.

 

[AZ_Ryan]

Amusing how so many people just 'know' stop start is bad without actual proper data or evidence.

Yes, stop start on an old engine from the 1980's without any modifications would be bad, but guess what, modern engines are designed to work with stop start.

They have coatings on bearings, different oils, better tolerances and even different designs. Many stop start setups now use an Integrated starter generator (ISG) rather than starter motor, ring gear, alternator etc so there are LESS moving parts. Even if they do use a starter motor it is designed to work in a stop start system with many more stops and starts (so you end up with a better starter motor)

Also just think for a minute. Hybrids such as the Toyota Prius start and stop all the time and they run for hundreds of thousands of miles without any problems at all. ALL PHEV, FHEV cars are stop start by default (and there are millions on the road) and the evidence for fuel savings is backed up by evidence.

People may not like stop start (although the US is more extreme than most countries) but saying it is bad doesn't make it so.

As mentioned by @GrabThatBlue - just because the car is built to tolerate it, doesn't mean it's good for it. Especially for a lousy 1 mpg. Start-up causes the most wear on an engine.

 

[Gregs24]

The biggest downside to stop/start is premature wear to the timing chain.

Timing chains rely on oil to keep all the links lubricated and from having the pins grind up against the links. Every time you stop the car, the links lose some of that oil and you get an absolutely microscopic and immesurable amount of wear. Do this ten or fifteen times a day, 5 days a week, half a decade, and you get a few fractions of a millimeter of slop in a single link.

Multiply that fraction of a millimeter across a few feet of chain, a couple dozen or so links, and now your timing is off.

This is the single biggest issue with stop start, in my opinion. I've seen it cause premature damage to motors at 1xx,xxx miles. Its not a problem with shorter chains, but on a longer set like on Audi's or the Coyote, its 100% a consideration in my mind.

Toyota don't seem to have had any problems.

All timing chains wear and most have very extended change intervals so whilst theoretically what you say may be true (although chain type and design will influence this) in reality it will make little or no difference to the replacement intervals. If it did they would be shorter and they are not.

 

[Gregs24]

Agm can be used in non s/s vehicles, in fact i put a red top in my ‘05 vette.

stop start doesn't actually stop the motor it simply puts the engine to sleep. The electric motor is still active for action even when the engine is stopped.

Yes indeed they can, although if you change a standard SLI type to AGM you must change the charge profile for it or you will shorten the life of the AGM battery.

Well the engine stops turning so by definition is stopped but as you say restarting is not like a cold start from fully off. In hybrids it is usually the transmission that restarts the engine using the HV battery.

 

[Gregs24]

As mentioned by @GrabThatBlue - just because the car is built to tolerate it, doesn't mean it's good for it. Especially for a lousy 1 mpg. Start-up causes the most wear on an engine.

Cold startup does yes. Not a hot start in a S/S system or hybrid.

Figures vary but up to 15% savings are possible, far more with a hybrid system.

 

[Cz_Ziemniak]

Toyota don't seem to have had any problems.

All timing chains wear and most have very extended change intervals so whilst theoretically what you say may be true (although chain type and design will influence this) in reality it will make little or no difference to the replacement intervals. If it did they would be shorter and they are not.

I'm quoting off of personal experience. Seen enough chain driven cars come in with timing issues for this exact reason.

The longer the chain, the more of a problem this will be. You don't see it in Toyota's since their chains are not typically a snake like that of the 4.2 found in Audi's.

If you drive the mustang enough in high stop/start situations, it is 100% a potential issue to look out for once you start getting up in the miles.

Whether or not you'll have to take the timing assembly apart before then is a different story, whether for phasers, guides, etc. But to not at least consider this as a possibility is rather shortsighted.

For this reason alone, I dislike Auto S/S

 

[Gregs24]

If I had wanted a hybrid I would have purchased one. If a SUV, then a SUV. If a truck, then a truck. I’m just saying that I DON’T LIKE IT IN MY MUSTANG.

We know - you have said it twice now!

Lots of performance cars are hybrids now

 

[AZ_Ryan]

Cold startup does yes. Not a hot start in a S/S system or hybrid.

Figures vary but up to 15% savings are possible, far more with a hybrid system.

Well enjoy your ASS. You seem to be the only person ive seen on any car forum advocating for it.

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