The full-size truck rivalry continues, as it has for decades, between Ford and Chevy, but this time with a high-tech twist. While Ford has received a lot of attention for its EcoBoost V-6 in the F-150, combining the fuel consumption of a V-6 with the power of a V-8, Chevrolet is claiming the Active Fuel Management system on the 5.3-liter V-8 in the Silverado offers comparable levels of fuel economy in a simpler, more proven package.

From a fuel-economy standpoint, the Silverado 5.3 and F-150 EcoBoost are in a near dead heat, with the 4x4 models getting an identical 15/21 EPA rating. The 2013 Chevrolet Silverado XFE model manages 1 mpg more on the highway, but falls one short of the 2WD F-150 EcoBoost in city fuel economy, with both models getting 22 mpg highway in EPA tests.

The EcoBoost V-6 and the 5.3-liter V-8 with AFM tackle the issue of fuel economy taking two distinctly different routes, but both essentially apply the principle of using less fuel during part-throttle or light-load operation. General Motors' approach runs the engine on four cylinders under light-load conditions, closing the valves to the deactivated cylinders by depressurizing the hydraulic lifters and shutting off the fuel injectors.

Ford's approach utilizes the smaller displacement and fewer cylinders of the V-6 to deliver more frugal fuel economy than a V-8, with the turbo boost delivering power and torque when needed under load. Chevrolet can legitimately claim its system is simpler and more proven, having debuted in the Silverado in 2007, and utilized on other GM models since 2005. But when it comes to power output, the Ford comes out decisively ahead, serving up 365 hp and 420 lb-ft of torque to the Chevy's 320 hp and 340 lb-ft. But with all-new full-size trucks just around the corner, GM will likely increase power and fuel economy on its next-generation trucks with the addition of direct injection.

You can bet the claims of competitive advantage will continue as new full-size models debut from GM and Chrysler over the next 6-12 months.

Source: General Motors