2011 Gmc Sierra 2500 H/d on 2040-cars

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Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.

GMC to get own model not shared with Chevy?

For years, GMC has existed as a brand without a single unique product, reconstituting Chevrolet trucks, SUVs and crossovers with more frosting in exchange for a few extra dollars. The Sierra is a Silverado, the Acadia a Traverse, and the Terrain an Equinox, although admittedly the latter pair are visually differentiated to a significant degree.
GMC could be set to expand beyond its Chevy-based roots, though. During last week's Detroit Auto Show press days, GM's product boss Mark Reuss was asked whether there'd ever be a GMC that wasn't taken from Chevy. "Oh, yes, you will," Reuss told the media. "The health of GMC is astonishingly good from a consideration standpoint." Reuss wouldn't elaborate on what the model could be, although we're quite happy to make some guesses. GMC has its bases fairly well covered, with a mid-size and full-size crossover, as well as a mid-size, full-size and HD pickup. We doubt GMC will be building a family sedan, sports car, or hatchback, so really, the only place we can see the brand going is into a smaller crossover.
Automotive News points out that the most recent small GMC showcar, the 2010 Granite concept (shown above), won't see production according to General Motors. That vehicle likely would have rode on GM's compact vehicle architecture, known internally as Gamma II, which underpins the Chevy Spark and Sonic, as well as the Buick Encore (and its overseas Opel/Vauxhall/Chevy counterparts).

Supercharged 2015 GMC Yukon Denali sounds evil, runs 0-60 in 4.5 seconds

Speeding along in a sports car is undoubtedly a ton of fun, but some owners need the ability to carry a lot of people and their stuff and don't want to sacrifice the ability to put the power down. The tuners over at Hennessey have that demographic covered with their growling, supercharged power kits for the GMC Yukon Denali. The upgrades come in three forms for the SUV's 6.2-liter V8: HPE550 with 557 horsepower, HPE600 with 605 hp and HPE650 with 665 hp. This video showcases the full-bore version, and this Denali can definitely hustle in a straight line. The power bump comes courtesy of a 2.9-liter supercharger, intercooler and high-flow cylinder heads to add over 200 horsepower compared to stock, and the final result is a bellowing SUV that rears up off he line to throw the driver back into the seat. The sprint to 60 miles per hour lasts just 4.5 seconds. Check out this hasty hauler in action in the video above.