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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 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.

Chevy Volt replacement battery cost varies wildly, up to $34,000

There's a growing hubbub in the plug-in vehicle community over what looks like some ridiculously cheap replacement batteries for the Chevrolet Volt going up for sale. GM Parts Online, for example, is selling a replacement Volt battery with an MSRP of $2,994.64 but, with an online discount, the price comes down to $2,305.88. For the 16-kWh pack in the 2012 Volt, that comes to a very low $144.11 per kilowatt hour (kWH). But is it a real deal? How can it be, when a Chevy dealer may quote you a price of up to $34,000 to replace the pack? For a 16-kWh Volt pack, $2,305.88 comes to a very low $144.11 per kWh. But is it a real deal? Battery packs in alternative propulsion vehicles are usually priced by the kWh and, historically, they've been thought to be in the range of $500-per-kWh for OEM offerings. Since automakers are understandably secretive about their costs, we still don't know what the real number is today, but we do know it varies by automaker. Tesla, for example, has said it pays less than $200-per-kWH at the cell level but, of course, a constructed pack would be more. Whatever is going on, li-ion battery prices are trending downward. So, $144.11 certainly sounds great, but what's the story here? Kevin Kelly, manager of electrification technology communications for General Motors, reminded AutoblogGreen that GM Parts Online is not the official GM parts website and that, "the costs indicated on the site are not what we would charge our dealers or owners for a replacement battery. There would be no cost to the Volt owner if their battery needs replacement or repair while the battery is under the eight year/100,000 mile limited warranty coverage provided by Chevrolet." A single price tag also can't be accurate for everyone, Kelly said. "If the customer needs to have their battery repaired beyond the warranty, the cost to them would vary depending on what needs to be replaced or repaired (i.e. number of modules, which specific internal components need replacement, etc.)." he said. "So, it's hard for us to tell you exactly what the cost would be to the customer because it varies depending on what might need to be repaired/replaced. As a result, the core charge would vary." But, is the $2,300 price even accurate for anyone? Thanks to a reader comment, we see that this similar item on New GM Parts makes it look like the lithium-ion modules that Kelly mentioned – where a lot of the expensive bits are – are not included.