2014 Gmc Sierra 1500 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 Recalling Another 2.7 Million Vehicles In Five Separate Campaigns

The recalls keep rolling in from General Motors, evidently keen to avoid repeating the mistakes of the ignition-switch debacle and clean house. This time they're all coming at once, with five separate recalls announced together covering approximately 2.7 million vehicles. The largest of the five actions involves over 2.4 million units of the previous-generation Chevrolet Malibu and Malibu Maxx, Pontiac G6 and Saturn Aura in order to fix brake light wiring harness, which have been found to be susceptible to corrosion. The recall is separate from the 56k Aura sedans which GM recently recalled over faulty shift cables, not to mention the previous massive recall of 1.3 million vehicles – some of them the same models – but appears to have resulted from the National Highway Traffic Safety Administration investigation that started with the G6 almost a year ago. The second-largest campaign involves the 2014 Chevy Malibu, specifically those fitted with GM's 2.5-liter engine and stop/start system, approximately 140,000 examples of which has been found to have problematic brakes. The issue does not appear to be connected to the recall of 8k Malibu and Buick LaCrosse sedans (also involving brake woes) which we reported upon last week. Four crashes have been reported in such models, but GM admits it's not yet clear if the problem was a contributing factor in the accidents. A further 112k Corvette models from the 2005-2007 model years are being called in for problems with their low-beam headlamps resulting from a flexing relay control circuit wire that's not meant to bend. GM says it is "aware of several hundred complaints" about this issue, but notes that there have been no reports of related accidents. In addition, over 19k examples of Cadillac CTS from the 2013 and 2014 model years are being recalled over windshield wipers that might not work after a jump start. Finally, GM is also bringing in 477 examples of its 2014 Chevy Silverado, Tahoe and GMC Sierra (though not the Yukon) to fix a problem with a tie rod in its steering rack. As ever, all recall repairs will be performed free of charge, and GM is now estimating that recall-related actions this quarter will result in an estimated $200-million charge against its second-quarter earnings. Read the full announcement from GM below for further details.

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.