Active Fuel Management to Replace GM's Displacement on Demand

So why change it if it's not broken? That's a good question, but not an unusual step for GM. After all, it has dropped some of its most

GM isn't about to change its Chevrolet Tahoe and GMC Yukon names, which, in all-new 2007 guise will be the first vehicles to debut the new AFM-equipped Vortec 5.3-litre V8. (Photo: General Motors of Canada)

reputable names in recent years, including its midsize Century nameplate that has been one of its most popular models for years, for new models that require expensive marketing campaigns just to build awareness.

Fortunately, GM isn't about to change its Chevrolet Tahoe and GMC Yukon names, which, in all-new 2007 guise will be the first vehicles to debut the new AFM-equipped Vortec 5.3-litre V8, after which it will become the new name for DoD for all 2007 model year vehicles equipped with the fuel saving technology.

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Like DoD, AFM reduces fuel consumption and cleans up toxic emissions by cutting power to four of the engine's eight cylinders, leading to a claimed 12 percent improvement in fuel economy. (Photo: General Motors of Canada)

DoD, AFM reduces fuel consumption and cleans up toxic emissions by cutting power to four of the engine's eight cylinders. The process works seamlessly, so no-one onboard the vehicle will be able to perceive a change has taken place. GM claims an efficiency gain of up to 12 percent, which is not quite as high as DaimlerChrysler's "up to 20 percent" claim, but neither is easy to substantiate.

What GM can substantiate, however, is that DoD is currently offered in more models than its rivals' cylinder-deactivation systems. A total of nine GM vehicles use the system, including the 2006 model year 5.3-litre V8-powered Buick Rainier, Chevrolet TrailBlazer, TrailBlazer EXT, Impala SS, Monte Carlo SS, GMC Envoy and Envoy XL, Pontiac Grand Prix GXP, and Saab 9-7X.