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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 execs fired over fraudulent India emissions testing

General Motors hadn't had a recall in India since 1995. That changed when it was discovered that certain employees were playing tricks with local emissions testing in order to ensure passing grades for engines. More than ten GM Powertrain employees in India and the US have been let go over the ensuing emissions flap, including Sam Winegarden, VP of global engine engineering, a man who has been with the company since 1969, leading development of some marquee powerplants.
According to Automotive News, an internal investigation revealed that employees "violated testing procedures," sometimes swapping specially prepared low-emissions engines during testing regimes for the Chevrolet Tavera SUV equipped with the 2.0-liter and 2.5-liter engines. Employees were also manipulating weights in order to get vehicles placed into different emissions categories. The discovery has led to GM recall the 114,000 Taveras produced over an eight-year period and halting their production and sale.
The Economic Times of India reports that the issue is due to "a faulty component." GM has developed a solution to the issue, and once it is validated in testing and approved by the Indian authorities, the recalled vehicles will be fixed at dealers and production will resume.

Chevy SS prototype spotted wearing Pontiac G8 clothes

Do not adjust your computer screen, you are not seeing the rebirth of the Pontiac brand. General Motors has chosen to use a G8 to disguise a test mule for the latest prototype of the forthcoming Chevrolet SS. The G8 was closely related to the Holden Commodore and Vauxhall VXR, the platform upon which the new Chevrolet performance model will be based. It should come as little surprise, then, that GM has opted to use the cladding from the former G8.
Thought the front clip of this mule is pure Pontiac, note the vents immediately behind the front wheel. That is a distinctive design hallmark of the Vauxhall VXR. Also note that this vehicle is right-hand drive, as the Holden and its Chevy counterpart will be very closely related. That likely includes potential drivetrains. The spy photos of this mule also reveal very wide rear tires, and rear wheels that do not match the fronts.