GM Charts Its Own Path to Boost Truck Fuel Economy

General Motors Co. is taking a different approach to pickup truck fuel efficiency than rivals Ford and Chrysler.

Powertrains for the company's all-new 2014 fullsize Chevrolet Silverado and GMC Sierra trucks will feature standard cylinder deactivation, direct fuel injection, variable valve timing, an 11:1 compression ratio and transmissions with only six forward speeds.

GM claims its strategy will deliver better real-world fuel economy than reducing engine size or adding transmission gears, as its domestic competitors are doing.

GM is rolling out three new engine options a 4.3-liter V-6, 5.3-liter V-8 and 6.2-liter V-8 for its 2014 trucks. Under light load conditions, the cylinder deactivation system shuts off four cylinders in the V-8s and two cylinders in the V-6.

Ford is downsizing to a turbocharged V-6 for its F-Series pickups for the sake of improved fuel efficiency. But GM contends its combination of high compression ratio and cylinder deactivation will outperform Ford's system during high engine load conditions.

GM also says it was able to avoid the complexity of an eight-speed transmission like the one Chrysler will adopt by boost the efficiency of its own six-speed transmission by recalibrating the gearbox, modifying the torque converter and adopting a quicker lockup.