2008 Gmc Sierra 3500 Hd Slt Crew Cab Pickup 4-door 6.6l on 2040-cars

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GM 6.2L EcoTec V8 rated at 21 mpg by the EPA

General Motors is already laying claim to best-in-class power for its new 6.2-liter V8 that will be offered in the 2014 Chevy Silverado and GMC Sierra this fall, and now it has released fuel economy numbers for the big engine. Available as an option on the Silverado LTZ and High Country (shown above) models as well as the the Sierra SLT and Denali trims, the 6.2L EcoTec3 V8 will return 15 miles per gallon in the city and 21 mpg on the highway on rear-wheel-drive trucks; these numbers drop by one mpg each on four-wheel-drive models.
These estimates are in addition to the engine's 420 horsepower, 460 pound-feet of torque and max trailering capacity of 12,000 pounds, and considering all that power it's not terribly far away from the fuel economy of GM's equally new 4.3-liter V6 and its rating of 18 mpg city and 24 mpg highway. This announcement comes just days after a report indicated that GM is unable to keep up with the demand of the 5.3-liter V8 in the fullsize Chevy and GMC trucks due to supplier issues. GM's official press release for the 6.2-liter V8's fuel economy is posted below.

2014 Chevrolet Silverado and GMC Sierra debut all-new designs, three new engines

General Motors has finally dropped the curtain on the 2014 Chevrolet Silverado and 2014 GMC Sierra. Both trucks have undergone substantial revisions with updated versions of the company's 4.3-liter V6, 5.3-liter V8 and 6.2-liter V8 engines. In a shot across the bows of both Ford and Chrysler, GM says it won't use a V6 engine adapted from passenger car applications. Instead, it developed the 4.3-liter engine based on its proven truck-duty architecture.
All three mills will boast direct injection fuel systems as well as a new cylinder head design. Combined with a revised piston, the new engines feature a smaller combustion chamber with a compression ratio of 11:1 or higher depending on the application. Cylinder deactivation and continuously variable valve timing are all part of the recipe, and each engine is paired with a six-speed automatic transmission with auto grade breaking. So far, no fuel economy or horsepower figures have been released, though GM says the new engines will best their predecessors in both areas.
Outside, the trucks feature a number of enhancements to reduce drag and wind noise, and GM claims both the Silverado and Sierra will offer buyers some of the quietest cabins in the class. Extended cab models now feature front-hinged rear doors to allow easier access to the back passenger area, and Crew Cab buyers can now select between a five-foot, eight-inch bed or a six-foot, six-inch bed. Buyers with a mind toward going off road will also rejoice in the return of the Z71 package, complete with Rancho shocks, front tow hooks and additional under-body protection.

2014 Chevrolet Silverado and GMC Sierra show all their sides in Detroit

There could hardly be more riding on the next-generation General Motors full-size pickup trucks, so the automaker has wisely made sure to have a selection of different models on hand at the Detroit Auto Show to show off. The 2014 Chevrolet Silverado and 2014 GMC Sierra were both officially introduced last month at a stand-alone reveal, and now they'll be on display for the public to see in various body configurations and trim levels.
The Silverado LTZ Crew Cab and Sierra SLE Extended Cab are aimed at providing more of a high-end pickup experience, while the Silverado LT Z71 Extended Cab and Sierra SLT Z71 Crew Cab should have off-road fans scouting out their favorite trails. The crew cab trucks won't go into production until sometime during the second quarter of this year - with other bodystyles coming later in the year - but we have plenty of live images from Detroit for you to enjoy.