1k with GM's Auto Stop System

[Scout1]

Just put a thousand miles on a 2014 Malibu LS with the new 2.5 Ecotec and 6 speed auto driving around New England on vacation. After noticing a strange "jolt" at intersections I realized the car has the new Auto-Stop system.

The system works pretty well but seems to often not "auto-stop". If you come to a stop too smoothly, the system thinks you might be in stop-and-go traffic and keeps the car running. If you brake abruptly, the system immediately stops the motor till you remove your foot from the brake. The starts were pretty quick and you can hear the regular starter noise when the care re-starts. Reading up on the system, it has a second battery to prevent dimming of the lights during auto-start and it has an electric trans fluid pump to keep the trans ready to go in an instant. Starter is supposed to be strengthened to handle the repeated cycles but I guess time will tell how long it will really last. Overall, I could live with the system but it is noticeable when you want to start in a hurry. Doesn't really delay anything, but you feel more of a jolt as the motor re-starts. You learn to remove your foot from the brake and wait an instant for the start to happen before you accelerate which makes the process smoother.

As for the Malibu itself, it drives nicely and the motor is VERY smooth for a 4-cyl but still has that buzzy sound as most 4-bangers do. Highway cruise is very quite (MUCH quieter than my 2013 Accord) and the suspension is good. Lousy visibility out the back though when backing up. The Ecotec, although rated as a strong motor feels kinda weak, more due to the transmission I think. You have to really rev it to feel the power. "Drive" grabs the upper gears at very low speeds so any throttle increase takes two down-shifts to get the car to accelerate which is kind of jerky. You can go to manual mode but the toggle switch on top of the shifter isn't very intuitive to change gears with.

Just thought I'd give my impressions! Oh, and the oil life monitor was down to 15% at 6000 miles which is when I turned the car back into Hertz - I would think on the original fill.

 

[demarpaint]

Can it be easily disabled? If not it is another technology I'd prefer to live without.

No offense intended to anyone who owns one.

 

[kam327]

I've read before the benefit only equates to roughly a half an mpg in normal driving. Given the cost and extra wear and tear on the drivetrain, definitely seems not worth it in the long run. Automakers need to concentrate on continuously improving the efficiency of the drivetrain, like Mazda's Skyactiv tech, and not waste their time or ours on this gimmicky stuff.

 

[JHZR2]

Im glad it is conservative in how it start-stops. IMO this is one of the most promising technologies out there... Think about how much fuel is wasted at stoplights and in stop and go traffic. The only downside is that you can't creep along in EV mode.

Too bad you can't get this in MT version so you can stop-start in out of gear coasting, etc.

It would be nice if there were a cheat sheet on how to invoke/prevent the operation. I had a rental buick regal "hybrid" of some sort, and it claimed to have stop-start, but I couldn't ever get it to work...

 

[JHZR2]

Originally Posted By: kam327
I've read before the benefit only equates to roughly a half an mpg in normal driving. Given the cost and extra wear and tear on the drivetrain, definitely seems not worth it in the long run. Automakers need to concentrate on continuously improving the efficiency of the drivetrain, like Mazda's Skyactiv tech, and not waste their time or ours on this gimmicky stuff.


Im sure if it were that big of a deal, UPS and Fedex would tell their drivers to idle their trucks for the five seconds it takes for them to deliver packages to suburban homes. Alas, they start-stop all the time.

Using a beefier starter, battery and a little controls logic is far simpler and straight forward than hybrids and other things that can get us better fuel economy.

 

[BMWTurboDzl]

I hate these systems although supposedly they're intelligent enough to keep the engine running when it's needed (i.e. A/C on hot days, heat on very cold days). I've noticed on BMW's system that the interior windshield develops scum much faster because the system pushes cool damp instead of cool dry air on warm but not hot days.

 

[dparm]

My M3 has it. Fortunately for US buyers, it defaults to OFF. All of the new BMWs default to ON in the US.

It's a stupid system that just puts more strain on the battery and starter. BMW even admitted it was purely for emissions and basically makes no difference to fuel economy (I verified this last summer, it was
And yes, the systems will not shut off the car every time. I read the BMW technical doc and it won't do it when the A/C is running, the steering wheel is turned, the engine is cold, etc.

 

[wallyuwl]

I had a Malibu with this system for a few days in the fall when my Equinox was in the shop with a warranty repair. I hated it! The jolt is very real and pretty harsh. Except for that it seems like a nice car, but that would be a deal breaker for me to buy one.

 

[CBR.worm]

I have two brothers with BMW's that do it, it can be disabled, but here with the AC on, the engine only stops for about 10 seconds max before jolting itself back to life. Seems almost useless except in hybrids where the start is smooth and seamless.

 

[Tzu]

I've heard GM has the best system, but I'm not sure if I would want it. I read that it can not be turned off, thus making a vehicle that has it off my shopping list. Where I live, there are nice country open roads with small town traffic, but not really city stop/go/ traffic jams. It would be interesting to rent a car like this and drive it a few days to work to really see how it would benefit me, but that's just for curiosity. My wife's '09 Sentra CVT she recently bought is averaging 37.7mpg with no start/stop feature. Pretty good if you ask me.

 

[dparm]

Originally Posted By: CBR.worm
I have two brothers with BMW's that do it, it can be disabled, but here with the AC on, the engine only stops for about 10 seconds max before jolting itself back to life. Seems almost useless except in hybrids where the start is smooth and seamless.


The jolt is bad in torque converter trans cars. On the manual and dual clutch systems, it is no different than the motor itself starting up.

 

[kam327]

Originally Posted By: JHZR2
Originally Posted By: kam327
I've read before the benefit only equates to roughly a half an mpg in normal driving. Given the cost and extra wear and tear on the drivetrain, definitely seems not worth it in the long run. Automakers need to concentrate on continuously improving the efficiency of the drivetrain, like Mazda's Skyactiv tech, and not waste their time or ours on this gimmicky stuff.


Im sure if it were that big of a deal, UPS and Fedex would tell their drivers to idle their trucks for the five seconds it takes for them to deliver packages to suburban homes. Alas, they start-stop all the time.

Using a beefier starter, battery and a little controls logic is far simpler and straight forward than hybrids and other things that can get us better fuel economy.


I'm not talking about UPS or other vehicles that spend an inordinate of time idling. I'm talking about 95% of U.S. Drivers.

And I'm not talking about hybrids. I'm talking about optimizing the combustion chamber and higher compression ratios and dry dual clutch transmissions and so on.

 

[IndyIan]

I'd think for some people in cities, the auto start might save quite a bit of fuel. I tried turning off the Neon at the one long light on my commute and it was noticable how much my trip mileage would increase.