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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 natural gas-powered vans recalled due to possible leak

General Motors is recalling almost 3,200 of its compressed-natural-gas powered utility vans because of possible leaks. GM and the National Highway Traffic Safety Administration (NHTSA) released a notice last week saying that 3,196 Chevrolet Express and GMC Savana CNG vans are on recall, though no accidents have been reported due to the possible issue. The recall is specifically for vans for model years ranging from 2011 to 2014. The recall stems from a potential leak from the compressed natural gas high-pressure regulator, and such a leak could cause a fire or explosion. GM will replace the vehicles' high-pressure regulator in order to fix the problem, will do it free of charge and is instructing owners to contact Chevrolet or GMC customer service to arrange for the parts replacement. Utility vehicle makers like General Motors have pushed for fleet sales of CNG-powered vans and trucks for the past few years and have touted them for their cheaper refueling costs relative to standard gasoline, not to mention the fact that natural gas can be readily sourced from throughout North America (thanks, fracking). According to CNGPrices.com, compressed natural gas sells for about $2.22 a gallon, on average, while the AAA is pegging the average price of gas at $3.34 a gallon. NHTSA has posted information on the recall here. Featured Gallery News Source: NHTSA via Reuters Green Chevrolet GM GMC Natural Gas Vehicles CNG gmc savana

The GMC Hummer EV could spawn a smaller electric truck

Over 90,000 motorists have reserved a GMC Hummer EV, and the truck's relative popularity has convinced executives to consider launching a smaller and presumably more affordable model. While nothing is official yet, the Hummer EV's smaller sibling could be a midsize pickup. Citing "people familiar with the matter," Automotive News reported a smaller Hummer EV exists in the design studio that General Motors operates in California. There's no word on what it looks like yet, though it presumably borrows at least some of the rugged-looking styling cues that characterize the controversial, 9,200-pound truck. Interestingly, the smaller model could bring the Hummer name to Europe. It's too early to provide technical specifications. The model hasn't received the proverbial green light for production but Automotive News added that it's a "priority project" and that it has "a good chance of going into production." If and when it does, it's reasonable to assume the truck will use the Ultium battery technology found under the full-size Hummer EV, among other electric models from General Motors. GMC hasn't commented on the report, and it hasn't announced plans to launch a second Hummer-branded electric pickup. If the report is accurate, the baby Hummer is at least a couple of years away from hitting showrooms. First, the Hummer EV SUV will enter production. We've been here before: a downward expansion is exactly how the now-defunct Hummer brand was born. The military-bred H1 spawned the H2 for 2002 and the H3 for 2006. An even smaller off-roader previewed by the 2008 HX concept was planned but ultimately canned. Related video: This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.