2004 Gmc Yukon Xl 1500 Denali 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 to get own model not shared with Chevy?

For years, GMC has existed as a brand without a single unique product, reconstituting Chevrolet trucks, SUVs and crossovers with more frosting in exchange for a few extra dollars. The Sierra is a Silverado, the Acadia a Traverse, and the Terrain an Equinox, although admittedly the latter pair are visually differentiated to a significant degree.
GMC could be set to expand beyond its Chevy-based roots, though. During last week's Detroit Auto Show press days, GM's product boss Mark Reuss was asked whether there'd ever be a GMC that wasn't taken from Chevy. "Oh, yes, you will," Reuss told the media. "The health of GMC is astonishingly good from a consideration standpoint." Reuss wouldn't elaborate on what the model could be, although we're quite happy to make some guesses. GMC has its bases fairly well covered, with a mid-size and full-size crossover, as well as a mid-size, full-size and HD pickup. We doubt GMC will be building a family sedan, sports car, or hatchback, so really, the only place we can see the brand going is into a smaller crossover.
Automotive News points out that the most recent small GMC showcar, the 2010 Granite concept (shown above), won't see production according to General Motors. That vehicle likely would have rode on GM's compact vehicle architecture, known internally as Gamma II, which underpins the Chevy Spark and Sonic, as well as the Buick Encore (and its overseas Opel/Vauxhall/Chevy counterparts).

GM is the latest automaker accused of diesel emissions cheating

Volkswagen and Ram need to make room on the diesel-emissions bench for General Motors. America's largest automaker was accused in a lawsuit on Thursday of rigging hundreds of thousands of diesel trucks with at least three so-called defeat devices to ensure that the trucks would meet federal and state emission standards, even if they generated more pollution in real-world driving. According to the complaint, on-road emissions testing conducted for the plaintiffs found that Duramax-equipped trucks produced NOx pollutants, comprised of nitrogen and oxygen atoms, two to five times higher than legally permitted, and "many times" higher than their gasoline counterparts. The proposed class-action lawsuit was filed in federal court in Detroit on behalf of people who own or lease more than 705,000 Chevrolet Silverado and GMC Sierra pickup trucks fitted with "Duramax" engines from 2011 to 2016 model years. The lawsuit seeks remedies including possible refunds or restitution for lost vehicle value, plus punitive damages. It adds to legal problems for Detroit-based GM, which has already paid about $2.5 billion in penalties and settlements over faulty ignition switches linked to 124 deaths. GM joins at least five automakers whose diesel emissions have been scrutinized by regulators or consumers. They include VW, which has admitted to cheating; Mercedes-Benz parent Daimler; Fiat Chrysler Automobiles, Peugeot and Renault. GM spokesman Dan Flores called the claims "baseless," and said the trucks comply with US Environmental Protection Agency emissions standards and California's own tough standards. Shares of GM were down 69 cents, or 2.1 percent, at $32.50 in afternoon trading, after earlier falling to $31.93. The GM lawsuit was filed by several law firms, including Hagens Berman Sobol Shapiro, which helped reach multibillion-dollar settlements with VW on behalf of drivers and dealers. The case is Fenner et al v General Motors LLC et al, US District Court, Eastern District of Michigan, No. 17-11661. The named plaintiffs are Andrei Fenner of Mountain View, California and Joshua Herman of Sulphur, Louisiana. They said they would not have bought their respective 2011 Sierra and 2016 Silverado trucks, or would have paid less for them, had they known about the alleged rigging. Joseph Spak, an RBC Capital Markets analyst, in a research report said "negative publicity" from the lawsuit could drive buyers to trucks from Ford or even Fiat Chrysler's Ram.