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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 patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging

Here are a few of our automotive guilty pleasures

It goes without saying, but I'll say it anyway. The world is full of cars, and just about as many of them are bad as are good. It's pretty easy to pick which fall into each category after giving them a thorough walkaround and, more important, driving them. But every once in a while, an automobile straddles the line somehow between good and bad — it may be hideously overpriced and therefore a marketplace failure, it may be stupid quick in a straight line but handles like a drunken noodle, or it may have an interior that looks like it was made of a mess of injection-molded Legos. Heck, maybe all three. Yet there's something special about some bad cars that actually makes them likable. The idea for this list came to me while I was browsing classified ads for cars within a few hundred miles of my house. I ran across a few oddballs and shared them with the rest of the team in our online chat room. It turns out several of us have a few automotive guilty pleasures that we're willing to admit to. We'll call a few of 'em out here. Feel free to share some of your own in the comments below. Dodge Neon SRT4 and Caliber SRT4: The Neon was a passably good and plucky little city car when it debuted for the 1995 model year. The Caliber, which replaced the aging Neon and sought to replace its friendly marketing campaign with something more sinister, was panned from the very outset for its cheap interior furnishings, but at least offered some decent utility with its hatchback shape. What the two little front-wheel-drive Dodge models have in common are their rip-roarin' SRT variants, each powered by turbocharged 2.4-liter four-cylinder engines. Known for their propensity to light up their front tires under hard acceleration, the duo were legitimately quick and fun to drive with a fantastic turbo whoosh that called to mind the early days of turbo technology. — Consumer Editor Jeremy Korzeniewski  Chevrolet HHR SS: Chevy's HHR SS came out early in my automotive journalism career, and I have fond memories of the press launch (and having dinner with Bob Lutz) that included plenty of tire-smoking hard launches and demonstrations of the manual transmission's no-lift shift feature. The 260-horsepower turbocharged four-cylinder was and still is a spunky little engine that makes the retro-inspired HHR a fun little hot rod that works quite well as a fun little daily driver.