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GM: new Sierra 5.3L V-8 EcoTec3 highway fuel economy tops Ford EcoBoost V-6

2014-5.3L V-8 EcoTec3-047
2014 5.3L V-8 EcoTec3 AFM VVT DI (L83) for Chevrolet Silverado and GMC Sierra. Click to enlarge.

The 2014 GMC Sierra 1500 full-size pickup truck features a new 5.3L EcoTec3 V-8 engine (earlier post) equipped with direct injection, cylinder deactivation (AFM) and variable valve timing to achieve EPA estimates of 16 mpg city (14.7 l/100 km) and 23 highway (10.2 l/100 km) with two-wheel drive or 16/22 mpg (14.7/10.7 l/100 km) with four-wheel drive.

In addition to highway fuel economy estimates that are 2 mpg higher than a 2013 Ford V8 pickup equipped with a 5.0L Ti-VCT V-8 and 3 mpg higher than a Ram V8, Sierra’s new V-8 highway fuel economy estimates also measure higher than those of the 2013 Ford F-150 EcoBoost V-6 (23 mpg for the Sierra, 22 mpg for the Ford EcoBoost F-150), GM noted.

2WD Pickup truck fuel economy comparisons
Model Engine Fuel economy Power
City mpg Hwy mpg
2014 GMC Sierra 5.3L EcoTec3 V-8 16 23 355 383
2013 Ford F-150 5.0L V-8 15 21 360 380
2013 Ford F-150 6.2L iVCT V-8 13 18 411 434
2013 Ford F-150 3.5L EcoBoost 16 22 365 420
2013 Ram 1500 5.7L HEMI V-8 14 20 395 407
2013 Ram 1500 4.7L V-8 14 20 310 330
Source: GM, Ford, Model Year 2013 EPA Fuel Economy Guide.

With an SAE-certified 355 hp (265 kW) and 383 lb-ft (519 N·m) of torque—increases of 40 hp and 48 lb-ft compared to the 2013 model—Sierra’s new 5.3L offers towing capacity of up to 11,500 pounds.

Most GMC owners—three out of four last year—will opt for the 5.3L V-8 engine, which is an $895 option, according to GM.

The 5.3L EcoTec3 V-8 is one of three more efficient new engines for the Sierra; a 4.3L EcoTec3 V-6 is standard. Sierra also will be available later this year with a new 6.2L EcoTec3 V-8 with more power, torque and capability than the 5.3L. Additional specifications for the 6.2L will be released later.

EcoTec3. Announced in December 2012, the new EcoTec3 engines feature three advanced technologies—direct injection, cylinder deactivation and continuously variable valve timing (CVVT)—to make the most of power, torque and efficiency across a broad range of operating conditions. The new engine family includes a 4.3L V6, a 5.3L V-8 and a 6.2L V-8, all matched with six-speed transmissions.

The EcoTec3 engines use direct fuel injection to optimize combustion over a broad range of conditions. The engines also feature a new cylinder-head design and a new, sculpted piston to optimize the mixing of air and fuel in the engine and the burning of the mixture to create power.

The heads features smaller combustion chambers shaped to complement the unique topography of the piston heads. The smaller chamber size and sculpted pistons produce a compression ratio of 11.0:1 or higher, depending on the engine, while the heads features large, rectangular intake ports with a slight twist to enhance mixture motion.

To further enhance combustion, the intake and exhaust valve positions have been switched from previous versions, and the valves are now slightly canted toward the cylinder centerline. Also, the spark plug angle has been revised and the electrode is now closer to the center of the chamber to support optimal combustion.

The pistons feature unique sculpted topography that was optimized via extensive computer analysis to precisely direct the fuel spray for better mixing and more complete combustion. The contours of the piston heads are machined after casting to ensure dimensional accuracy.

Cylinder deactivation, also known as Active Fuel Management (AFM), is now standard on all three engines for the Silverado and Sierra 1500.

The system uses oil pressure, controlled by the powertrain control module, to deactivate the lifters on selected cylinders, closing the valves for those cylinders. It deactivates four of the cylinders on the V-8 engines and two cylinders on the V-6 under light load conditions—operating the engines as a V-4—and seamlessly reactivates the cylinders when the driver demands greater power. The transition takes less than 20 milliseconds and is virtually imperceptible.



16 mpg? That is a criminally pathetic figure. Get a real car that gets 50mpg, not this abomination.

Will S

As long as it is used by a business with a need to haul heavy material, this is better than the current. Of course, it may also be bought by those who want a big truck predominantly for the image factor. THAT would indeed be pathetic...


At one time , I lived in eastern Massachusetts and drove a smaller car. I never drove off road and never needed to carry a large load. In fact, I usually rode my bicycle to work. I now work in the agricultural machinery industry in Utah and often need to carry a large load and sometimes drive on roads that would destroy a crossover SUV. I have a small car but I normally need to use my 4WD Long Bed Silverado pickup. Occasionally, I need use to even larger truck with a 30 ft trailer to haul parts.

Anyway, not everyone has the same requirements. Also, if you look at the full article from GM,

it is interesting to note that not only does GM do slightly better than the Ford V6 turbo boost but the worst vehicle is the full size Nissan pickup and the next worse vehicle is the full size Toyota pickup GM beats both of these by more than 25% and has a higher rated load


In general, people do not buy the Nissan and the Toyota vehicles for efficiency - they buy them for the image factor.


There really is nothing like a big block V-8. I love mine and will never own a vehicle again with less could be a 400 HP electric vehicle though - doesn't necessarily need to be an ICE.


The next question is, what's Ford going to do to beat GM?  Going to a small overexpansion (Miller cycle) would reduce output but increase thermal efficiency.


Ford wants to lower the weight 500lbs on their pickups

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