February 11, 2013
Ecotec 3 6.2L V8. Click image to enlarge
Article by Justin Pritchard, photos courtesy GM
Chevrolet Silverado and GMC Sierra Ecotec 3 Engine Lineup
To the elation of GMC and Chevrolet truck and 4×4 enthusiasts across the internet, the new breed of GM trucks and utility vehicles is readying for a sales launch later this year.
Tony DiSalle, vice president of GMC Marketing, says “these trucks have all the power and capability that’s expected in today’s market, excellent fuel efficiency, plus a lot of unexpected, purposeful features developed with truck owners in mind.”
The new GMC Sierra, Chevrolet Silverado, and associated SUV variants (Tahoe/Yukon/Suburban) will soon hit dealers in a variety of models and trim levels that pack new features, new styling, new safety implements and new technologies.
They’ll also pack an all-new engine lineup, which consists of a 5.3L V8, a 6.2L V8 and a 4.3L V6. Displacements are the same as the last generation trucks, but GM officials say the engines only share a ‘handful’ of parts with the outgoing power units.
Dubbed ‘Ecotec 3’, the new family of GM truck engines promises plenty of durability, as well as some of the latest fuel-saving technologies included as standard.
Here’s a closer look at how GM says the Ecotec 3 powerplant range works hard to extract more clicks from every litre.
Ecotec 3 5.3L V8. Click image to enlarge. Click image to enlarge
Active Fuel Management: When full performance isn’t required, the Ecotec 3 engines can turn off cylinders selectively, reducing the engine’s need for fuel.
Unless you’re driving a Smart Fortwo, sustained cruising down the highway requires only a fraction of the engine’s available power. In this situation, Ecotec 3 engines ‘turn off’ half of their cylinders while nobody’s looking, to help cut down on needless drinking.
How’s it work? Advanced engine controls cancel fuel injection to these cylinders, and a hydraulic valve control mechanism keeps the intake and exhaust valves on the deactivated cylinders closed. In this situation, gases in the deactivated cylinders are compressed over and over again, resulting in a ‘gas spring’ effect that helps the four running cylinders operate more easily.
The entire system is computer controlled, and actuated by solenoids and oil pressure. It’s invisible to the driver, other than a small display in the instrument cluster that references the engagement of four-cylinder mode.
“We chose to keep the proven capability of our larger V8 truck engines, and save fuel by switching off half of the cylinders when they aren’t needed” said Jordan Lee, global chief engineer for small block engines.
He goes on to further diss Ford.
“Rather than adapting a V6 intended for use in passenger cars, we built a new engine from the ground up based on the unique demands of a truck. Sierra’s 4.3L engine shares its basic design architecture with the latest iterations of the V8 engines that GMC owners have trusted for generations”.
Interestingly, GM officials say their AFM technology allowed them to stay away from a smaller-displacement, turbocharged engine (a la Ford Ecoboost) for long-term durability. Drivers will also benefit from a proper exhaust note at full throttle, which is not a characteristic of the Ecoboost mill from Ford.