I have had it in a few loaner/rental cars and really dislike it. The stop part isn't so bad but the shudder through the car when it restarts is a real turn-off. In the XT5 I had as a loaner, between this and the awful electronic beer tap shifter I swore I would never want one.

 

I'm not against stop start but there are some problems. The AC compressor does shut off and there is a very noticeable increase in cabin temperature and the related musty smell. I live in Phoenix and when it gets hot (90F and over) the system doesn't even activate. An electric compressor would significantly allow more off time. Additionally the transmission has an accumulator to help maintain line pressure. It has a limited amount of off time before you get into shift problems. The technology has a long ways to go before full customer acceptance.

 

IMHO - this is a bigger benefit to the car manufactures than the customer. Another "You just don't how much you need this." BS just like run flats.

 

And to add to David's comment you aren't going to gain much efficiency by going to an electrically driven compressor versus running the engine. With the electric powered compressor you are converting mechanical to electrical via the alternator and then electrical back to mechanical via the electric motor and neither process is close to 100% efficient, of course storing power in the battery to power the compressor during off time involves electrical to chemical and chemical to electrical conversions with another loss of energy.

To some extent going to an electric compressor is likely to happen because of other advantages; mounting location no longer has to be in plane with the drive belt, it can operate at an efficient speed regardless of engine RPM, and problems of designing a compressor that functions effectively at low RPM while withstanding high RPM disappear. The electric cooling fan which has largely replaced the belt driven fan provides similar advantages in providing air flow independent of engine speed but the power to run it still has to be generated by the engine so in terms of overall efficiency it isn't much better than the older engine driven clutch fans in many applications. But packaging efficiency is a winner for electric fans (and compressors) and the electric fan solved the issue of generating cooling airflow with a transverse mounted engine.

 

These cars have "smart" alternator programming that only charges the battery when it is efficient to do so--such as during deceleration--so the effect of running electrical items is not as inefficient as it used to be.

 

The one quality of the system that drives me nuts is the way it identifies that you have come to a complete stop. The system seems to immediately stop the engine as soon as speed drops below 1 mph. I tend to brake normally and then release brake pedal pressure as I come to a full stop to make a nice gentle stop. But in many, many of my stops, i am still rolling forward at a very slow speed (say .5 mph, but with foot still on the brake) and the engine shuts down. This causes a sudden lurching stop of the car. Very un-luxury car like.

 

I also have trouble inching into my garage. I have very little room and it has to be parked just right--but then the engine shuts off.

 

*sigh*.. we can still buy a car with a manual transmission but we are losing manual control of everything else.

 

@next2pool, Yes! same here. I too have a narrow space to park and have hung a tennis ball from the ceiling to help me know when to stop. Many times the engine stops with a thud just as I'm inching forward.

 

This is the social engineering side of fuel saving at play-soon you will be shutting off the engine as you enter your garage and pushing your car into place thus saving even more gasoline

 

Damn CAFE standards! I'll happily convert from gasoline once the last dead dinosaur is combusted in my cylinder..

 

I just shut off the Auto Stop as i am approaching my house, or any place i don't want it to engage. yes, it's one more thing to do but it's easy and i love not burning premium gas at stop lights!

 

I had a new XT5 while my CTS was in for a new transmission install. The stop start was almost imperceptible and I could live with it. In the XT5 you can't over ride it. Today I got my CTS back with the new trans and frankly, the start/stop is now as good as the XT5--BTW my ATS does not have stop/start.

 

Thankfully, my 2016 ATS Premium AWD 3.6 non turbo has the Disable Button .. So I turn it OFF as soon as I start the engine.

 

My 2017 has an on-off switch on the center console for the auto-stop. Maybe now that I read this issues of excess wear, I will turn it off.

 

I turn it off when I get into the car. I don't care for the shudder when auto is on and the car starts at a light or stop sign. Im pretty much in the habit now of shutting it off after I do up my seatbelt.