2007 Sierra 2500 Slt Gmc Diesel 4x4 2007.5 Z71 Chrome Wheels Short Bed 2008 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.

2018 GMC Acadia with 'Christmas Aero' modification gets in the wind tunnel

Tis the season of "Big" - big cheer, big parties, big bowls of eggnog, big decorations, and when it comes to your family hauler, big drag. Festive drivers who festoon their crossovers, minivans, and SUVs with wreaths, Rudolph noses, fuzzy antlers, and rooftop Christmas trees undo the years of work that car engineers devote to fractional gains in fuel economy. To put numbers to such fuel-guzzling madness, GMC started with a 2018 Acadia, optioned it with the Xmas Aero Package - both Standard and Plus versions - put it in Lockheed-Martin's wind tunnel. The resulting dip in fuel economy results probably won't surprise anyone who's used a roof rack - or, for that matter, their car's air conditioning. However, it might surprise you to find out which seemingly substantial decoration had no effect, and which seemingly innocuous decoration was about twice as bad as running the A/C on its Mr. Freeze setting. Check out the brief video above for the results. And consider placement of that bow carefully.

Who sold the most heavy-duty pickups in 2012? PickupTrucks.com investigates

Domestic manufacturers enjoyed a good year for heavy-duty pickup sales in 2012. PickupTrucks.com has taken a close look at exactly how those sales broke down between each manufacturer and between three-quarter and one-ton pickups. Ford sold some 67,786 F-250 Super Duty models last year with the Chevrolet Silverado 2500 HD falling just behind at 56,359 units. The Ram 2500 HD came in third at 41,918, while the GMC Sierra 2500 HD earned itself fourth place with 27,616 deliveries. While Ford held onto the top spot in the one-ton market, Ram easily nailed down second place by selling more 3500 HD models last year than General Motors sold Silverado 3500 HD and Sierra 3500 HD trucks combined.
So, did GM manage to sell more trucks than Ford with its two brands? Very nearly. Ford sold a total of 119,338 heavy-duty pickups to GM's 111,555. Ram, meanwhile, moved a distant 77,583. But perhaps more interesting is the diesel take rate in this segment. PickupTrucks.com says 80 percent of all domestic one-ton trucks roll from the dealer lot with a turbo-diesel under the hood. Head over to the site for a closer look at the breakdown.