The global microchip shortage has resulted in numerous production cuts and limited availability for a number of features on new GM vehicles, as GM Authority has covered in the past. That includes the removal of automatic engine-stop start from GM’s line of full-size trucks and SUVs. We’ve already examined how the feature’s removal affects the fuel mileage of the 2021 Chevy Silverado 1500 and 2021 GMC Sierra 1500, and now, we’re taking a look at how the removal of automatic engine stop-start affects mpg figures for the 2021 Chevy Suburban.
For those readers who may not know, automatic engine stop-start is designed to increase fuel economy and lower emissions by cutting the engine as soon as a vehicle comes to a stop, including at a stop sign, stop light, or in traffic. Once the driver removes their foot from the brake pedal, the engine will automatically spark back to life, allowing the driver to progress forward.
However, due to the global microchip shortage, this feature has been removed from some new 2021 Chevy Suburban models, namely those equipped with the naturally aspirated 6.2L V8 L87 gasoline engine, which produces 420 horsepower at 5,600 rpm and 460 pound-feet of torque at 4,100 rpm. The 6.2L V8 L87 connects to a 10-speed automatic transmission, driving either the rear wheels, or all four wheels.
As of June 7th, 2021, new 2021 Chevy Suburban models equipped with the naturally aspirated 6.2L V8 L87 gasoline engine are no longer equipped with automatic engine stop-start. As a result, fuel economy is down by 1 mpg in the city, with rear-wheel drive models rated at 14 mpg in the metric and 4WD models rated at 13 mpg in the metric. Combined mpg for rear-wheel drive models is also down by 1 mpg.
Additionally, new 2021 Chevy Suburban models equipped with the naturally 5.3L V8 L84 which were produced after June 7th, 2021 also see a fuel economy decrease without automatic engine stop-start, losing 1 mpg in the city and 1 mpg combined when equipped with rear-wheel drive, and losing 1 mpg combined when equipped with four-wheel drive.
Meanwhile, the 2021 Chevy Suburban is also offered with the 3.0L I6 LM2 turbodiesel Duramax, which continues to come equipped with automatic engine stop-start.
| Drivetrain | Engine | Transmission | Auto Stop/Start | City mpg | Highway mpg | Combined mpg | Effective Date |
|---|---|---|---|---|---|---|---|
| 2WD | 5.3L V8 L84 | 10-speed auto | Yes | 16 | 20 | 18 | Start of 2021 MY |
| 2WD | 5.3L V8 L84 | 10-speed auto | No | 15 | 20 | 17 | June 7, 2021 |
| 4WD | 5.3L V8 L84 | 10-speed auto | Yes | 15 | 19 | 17 | Start of 2021 MY |
| 4WD | 5.3L V8 L84 | 10-speed auto | No | 15 | 19 | 16 | June 7, 2021 |
| 2WD | 6.2L V8 L87 | 10-speed auto | Yes | 15 | 20 | 17 | Start of 2021 MY |
| 2WD | 6.2L V8 L87 | 10-speed auto | No | 14 | 20 | 16 | June 7, 2021 |
| 4WD | 6.2L V8 L87 | 10-speed auto | Yes | 14 | 19 | 16 | Start of 2021 MY |
| 4WD | 6.2L V8 L87 | 10-speed auto | No | 13 | 19 | 16 | June 7, 2021 |
| 2WD | Turbodiesel 3.0L I6 LM2 | 10-speed auto | Yes | 21 | 27 | 23 | Start of 2021 MY |
| 4WD | Turbodiesel 3.0L I6 LM2 | 10-speed auto | Yes | 20 | 26 | 22 | Start of 2021 MY |
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Comments
13 city! Did we suddenly go back to 1975?
No in 1975 13 was highway mpg on a 454
13 city mpg is the same as my 2002 GMC Sierra SLT 4WD.
With no variable valve timing nonsense, no active fuel management bs, no direct injection, and gummed up intake valve crap, no failing lifters, no stop start bs, a reliable, simple and fuel efficient 4 speed automatic that doesn’t have goofy shifting and bad logic that needs *reprogrammed*.
New car buyers are really fools with $$$ and shouldn’t be rewarded with stimulus checks.
Have owners/buyers of these vehicles equipped with stop/start ever considered how often their starters will wear out ? No wonder there are aftermarket gizmos to defeat this technology.
This was done to appease EPA, I don’t believe the numbers because I know people who have the stop/start and their mpg is no where near theirs.
Well, the drop in economy from 14 to 13 MPG for vehicle were driven the average 15,000 miles per year results results in burning 82 more gallons of fuel. Unleaded regular is now about three bucks, so that’s an extra $250 out of the owner’s pocket. That is assuming the worst case scenario if all driving is city.
The question is how much will it cost if the starter needs more frequent replacement? If the starter lasts more than a few years, the savings are probably outweigh the wear and tear.
I have to admit I don’t like stop/start the way GM implemented it using the conventional starter because of the lag. On the other hand, I have 2001 and 2003 Honda insights which have an electric assist motor integrated in the flywheel. The Insights start virtually instantaneously – no cranking.
This, it has been independently tested numerous times and shows a 5-8% savings which is roughly $100+ a year. That alone covers a battery or starter. But they strengthened the starter so it will last just as long as the typical starter and batter tech has increased as well. This doesn’t add any more undue stress (the oils today coat the parts plenty so there isn’t added wear at start up either) rather just cost savings as idling is one of the most wasteful time for an ICE vehicle.
Since this only works with the A/C off and the heat off in reality your $100 per year savings is mute. Only in mild climates where air conditioning or heat is not needed will this be effective. Son in law was reading about it this AM in the owners manual of his new GMC, we live in TN where AC is used from May until Nov., then we get 2-3 weeks before we need heat, same from mid Nov. until Apr. this feature was designed for EPA purposes only, most people I know disable it because it’s a hassle to put up with it.
Not quite. If it’s very cold, below 0F or very hot, over 95F, the stop start is disabled. In my ’16 Malibu LT, the A/C can be set to either normal or normal +, with the stop interval of 1 min and 2 mins respectively. The fan continues to run to get the last of the cold air out of the system.
Same for heat. In cold weather, the stop/start doesn’t engage until the engine is at full operating temperature, which obviously takes less time if it’s warm out.
Dang, if only the designers and engineers thought of this and there was the ability to beef up and put a strong starter motor on these things that wouldn’t be a problem. Oh wait, they did think of that and the starting system was strengthened to handle this. It is a non issue, it isn’t going to fail in 3-4 years they will last a long time; all that was considered when knowing and designing the system to not just start once per drive but many times per drive.
I’ve yet to have a customer buy a Suburban because it was equipped with Auto Start/Stop….
My 2020 trail boss only get 14-15 mpg overall with S S. Still much better than my 1965 riviera I drove in high school which got 8 on the highway, but chevron custom Supreme was only 34.9 cents per gallon then
Really wish cars were as cheap as they were back then😕 I remember trying to get a Plymouth Satellite SuperBird but they were in just so high in demand that I was stuck buying a Mustang Mach1 which I liked but it wasn’t comparable to the superbird that I test drove. Wish I would’ve kept the Mach 1 considering how crappy cars are today (though not as bad as the ones from the 90s) but the wife made me get a station wagon then a Suburban. I swear that suburban literally makes as much as the old one including mine from the 80s. GM has all this “eco friendly tech” but they just can’t build it right like Ford and other companies have. It’s not that hard. You have one battery for accessories such as the climate control and stereo and another battery for the starter. Cylinder deactivation is a bit more complicated but it just seems so rough compared to the competition from my experience since I like to hop around with brands. Of course it’s a V8 so your never going to get great fuel economy but it shouldn’t be that bad.
Superbirds sat on the lot for years. I remember them being lined up like they were trying to give them away.
I have to beleive the 1MPG is a rounding error. The amount of fuel used at idle is nothing. In the winter I start my suburban as much as 15 minutes early so it’s warm when I get in it. There is no detectable decrease in the average MPG due to this winter change in usage. The start stop function is some trickery to appease the EPA.
If GM got rid of the Active Fuel Management and Dynamic Fuel Management on the Suburban, sales would increase. Toyota and Nissan doesn’t have it on their full size SUVs.
The stop/ start feature is a fad that hopefully will disappear like the 8track cassette ,nothing is scarier than pulling into a busy rotary when the engine stops. Everybody I know disconnects the foolish thing. GM needs reliability not tricks,PK