2003 Gmc Sierra 3500 Slt Crew Cab Pickup 4-door 6.6l 4x4 on 2040-cars

Auto blog

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.

2019 GMC Yukon Graphite Edition offers Denali engine and features without the chrome

A sporty-looking option package called RST was recently introduced for the Chevy Tahoe and Suburban that also offered the option of a 6.2-liter V8 and magnetic suspension. Now GMC is getting in on the action with the GMC Yukon and Yukon XL Graphite Edition. The trim package adds a number of visual enhancements, and, if you're so inclined, has a performance version with the same 6.2-liter V8 and magnetic suspension as the Tahoe RST and Yukon Denali. As for appearances, the Graphite Edition adds black trim almost everywhere, including the roof rails, grille, fog light surrounds, and window surrounds. It also adds 22-inch wheels, regardless of whether it's just the appearance version or the performance version. The appearance package has machined-finish wheels, and the performance package has black painted wheels. As previously mentioned, the performance version of the Graphite Edition adds magnetic suspension and the 6.2-liter V8 with 420 horsepower and 460 pound-feet of torque found on the Denali and the Tahoe and Suburban RSTs. It's coupled to a 10-speed automatic transmission, and gets a rear axle ratio of 3.23:1. It also gets a few other Denali features such as a color heads-up display, Bose noise cancellation, a 170-amp alternator, and a trailer brake controller. The Graphite Edition can be had with both two-wheel drive or four-wheel drive. The Graphite Edition can only be had on Yukon and Yukon XL SLT models. Pricing hasn't been announced yet, but it's likely it will be a bit more affordable than buying a Denali model. Related Video: Featured Gallery 2019 GMC Yukon SLT Graphite Edition Image Credit: GMC GMC SUV gmc yukon gmc yukon denali

Canada opens probe into 250,000 GM pickups, SUVs over brake performance

Transport Canada, the auto safety regulator, has opened a probe into braking issues in nearly 250,000 General Motors full-size pickups and SUVs after U.S. officials launched a similar probe last year, the agency said on its website. The U.S. National Highway Traffic Safety Administration (NHTSA) in November into 2.73 million U.S. 2014-2016 model year SUVs and pickups after receiving 487 reports of hard brake pedal effort accompanied by extended stopping distance that were attributed to deterioration of the engine-driven brake assist vacuum pump. Transport Canada's probe covers 249,700 2015 through 2017 model year vehicles including the Cadillac Escalade, Chevrolet Suburban, Chevrolet Tahoe and GMC Yukon as well as 2014-2017 Chevrolet Silverado LD and GMC Sierra LD vehicles. The U.S. agency said it had reports of nine incidents of vehicles incurring damage as a result of colliding with another vehicle or fixed object at low speeds and reports of two injuries. NHTSA said if the pump fails to operate, the amount of brake power assist can be significantly reduced, extending vehicle stopping distance. The NHTSA sent GM an information request in a Feb. 7 letter. A GM spokesman said he had no update on the investigation. Reporting by David Shepardson; editing by Jonathan Oatis