2007 Sierra 2500hd Diesel 4x4 Slt Crew Heated Leather Bose 1 Owner 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.

GM tinkering with Silverado, Sierra model mix amidst strong early sales

Variety, as they say, is the spice of life. That's a lesson that is currently being taught to General Motors, because despite a strong showing from its 2014 Chevrolet Silverado and GMC Sierra, the General's pickup sales still can't best those of cross-town rival Ford.
With 59,163 trucks moved, GM fell just over 1,000 units short of toppling Ford, and one of the main reasons for that, according to GM's chief sales analyst, was due to a lack of variety in the engines and body styles available on dealer lots. "We are still over-weighted toward crew-cab V8 trucks. Our light-duty mix will moderate over time as our launch progresses," said Kurt McNeil.
Loading dealers with the popular combination of the 5.3-liter V8 and the four-door, Crew Cab body style was intentional during the truck's launch, but as supplies of leftover 2013 models, which are being sold at heavy incentives, are beginning to wane, both budget-conscious and high-dollar buyers are looking elsewhere instead of at the volume model pickups.

GM confirms 2015 Silverado, Sierra to get 8-speed automatic

When viewed alongside the next Ford F-150 and the Ram 1500, there is one thing that seems to be missing from the Chevrolet Silverado and GMC Sierra. Where the F-150 will rely on turbocharging and aluminum architecture and the Ram sports an eight-speed automatic and an air suspension, the General Motors twins lack a big, calling-card feature. They're very good, very refined trucks, but one could argue that they're not terribly innovative.
And while it might not be as flashy a feature as air suspension or a lightweight skin, the Silverado and Sierra will get their own eight-speed automatic for 2015, a transmission that will be paired with the company's Ecotec3 6.2-liter V8. The new cogswapper will also find its way into the GMC Yukon Denali, but for now, there's no indication why the Cadillac Escalade, Suburban, Tahoe and standard Yukon are being left out.
According to GM, the new gearbox is about the same size and weight as the current Hydra-Matic 6L80 six-speed. By the time the new powertrain combination enters production late this year, the EPA will almost certainly have gotten around to certifying the vehicles' fuel efficiency. Until then, feel free to speculate. The current Silverado with the 6.2 and six-speed auto returns 14 miles per gallon in the city and 20 on the highway. How much do you think the eight-speed will improve those figures? Scroll down for the official press blast from General Motors, and then head into Comments.