2021 Gmc Sierra 1500 At4 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 Syclone spools up a storm on Jay Leno's Garage

A storm was brewing on American roads in the early 1990s. That's when Detroit's automakers were producing some of the hottest performance trucks ever devised – models like the Ford Lightning, GMC Typhoon, and its flyweight pickup sibling, the GMC Syclone. Jay Leno just happens to have one of the latter in his garage, and took it out to showcase in this latest video segment. The Syclone was an exercise in absurdity, and could not only trounce any other pickup on the road, it could outrun anything else GM made and just about anything else on the road – beating Ferraris and Porsches off the line. In a pickup, for crying out loud. The kicker is that its engine wasn't such a monster, either: under the hood sat a 4.3-liter turbocharged V6 pumping out what would seem by today's standards to be an adequate 280 horsepower and 350 pound-feet of torque. Even the smaller of the EcoBoost V6s available in today's Ford F-150 produces more than that. But in a lightweight, compact pickup, those figures were enough to propel the Syclone to 60 in 4.3 seconds and run the quarter-mile in 13.6 seconds. Long before the dune-jumping Ford F-150 SVT Raptor or even the Viper-powered Dodge Ram SRT-10, GM made fewer than 3,000 Syclones based on the compact Sonoma (sister to the Chevy S-10) and another 4,700 of the Typhoon, which was mechanically similar but more practical (albeit heavier) wagon bodywork from the Jimmy. But as Jay aptly points out, the Syclone was the one you wanted. Scope it out in the ten-minute video clip above.

GM issues 4 new recalls for 90k vehicles, Chevy, Buick, GMC affected

One day after releasing an internal report that found a pattern of "incompetence and neglect" within the company, General Motors announced four more recalls that affect 89,126 vehicles. One of the recalls affects 31,520 vehicles that may contain a defect that could prevent airbags from deploying in a car accident. GM said it was aware of at least one crash in which a vehicle occupant sustained an injury because the airbags didn't deploy when they should have. The company said it was aware of other crashes that were similar in nature, but it is not yet known whether they're related to the condition, in which the shorting bar inside the driver's airbag may occasionally contact the airbag terminals. If the car and terminals are touching each other in a crash, the bags will not deploy. Vehicles from the 2012 model year are affected by the problem, and they include the Buick Verano, Chevrolet Camaro, Cruze and Sonic. GM has conducted two previous recalls for this condition involving 7,116 cars. GM is also recalling 57,512 models of the 2014 Chevrolet Silverado 1500, 2014 GMC Sierra 1500 and 2015 Silverado HD, Tahoe and Surburan, as well as the 2015 GMC Sierra HD, Yukon and Yukon XL models because their radio control modules may not work, and thus prevent certain audible safety warnings. Certain models of the 2013-2014 Chevrolet Spark and 2013 Buick Encore are being recalled for a different airbag problem, which could prevent airbags from deploying properly during a crash. And 33 2014 Chevrolet Corvettes are being recalled for yet another airbag problem, in which an internal short circuit could disable the airbags. So far in 2014, General Motors has issued 34 separate recalls that affect approximately 15.9 million vehicles – more than the company has sold in the past five years combined. GM Announces Four Recalls DETROIT – General Motors today announced three safety recalls and one non-compliance recall, all of which were reported to the NHTSA on Thursday, June 5, 2014. In all cases, customers will receive letters from GM letting them know when they can bring their vehicles into a dealership, where all repairs will be performed free of charge and courtesy transportation would be provided as needed.