But why did GM insist on fitting a 6.0-liter V-8 cranking out 332 horsepower for the hybrid application? Performance is definitely important to truck guys and gals, but it seems a shame that GM avoided the opportunity to deliver a full-size truck that soars past 25 mpg on the highway. With its high-torque electric motors ensuring healthy around-town performance, it seems superfluous to have all those cubic inches sucking gasoline underhood. In fact, in GM's upcoming baby Duramax Diesel, efficiency is rumored to meet or exceed 30 mpg, and its workhorse engine should easily meet the 6,100-pound tow rating of the Sierra Hybrid. At 4.5 liters and with a turbocharger that boosts performance only when truly needed, the Duramax approach seems more intelligent for finding the happy medium between performance and efficiency. Mercedes makes do with only 3.0 liters for its 5,000-pound-plus GL320 BlueTEC clean diesel SUV, and as such that vehicle edges close to 30 mpg on the highway.
The Sierra Hybrid starts at a pretty steep $39,365 for the most basic 2WD setup, no small change. But federal tax incentives of up to $2,200 for many customers help ease the sticker shock and recoup the price of the tech-heavy hybrid system. And GM's new trucks have made leaps and bounds in refinement, comfort, and drivability, so rest assured this is no crude beast of burden. However, unless you frequently haul big loads or seriously need the capability of a pickup, you'd be better served by one of GM's own mild hybrid sedans (i.e. Chevy Malibu Hybrid) that easily surpass 30 mpg on the highway. Or perhaps a new clean diesel like the VW Jetta TDI, which handily earns 40-plus mpg on the highway (or 58 mpg in the hands of mileage-busting couple John and Helen Taylor).
GM co-developed the two-mode system with BMW, Mercedes, and Chrysler, and it can be found also on the recently departed Chrysler Aspen/Dodge Durango SUV hybrids (does the world really want big, heavy hybrids?), on GM's Escalade and Tahoe hybrids, as well as on BMW's sybaritic new 7 Series active hybrid. None of these vehicles can be considered fuel misers, but we welcome their significant reduction in consumption, moving them from from the uber-thirsty teens to the semi-thirsty 20s. That's progress we can believe in, and change we're glad auto companies are investing in.--Colin Mathews
2009 GMC Sierra Hybrid Crew CabEnlarge Photo