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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.

Car and Driver reveals spy shots of mid-engine 2017 Corvette

Some news in the car world is perennial, and some is perennially wrong. Typically news about some upcoming mid-engined Chevy Corvette has fallen into the latter category, with rumors never yet generating a road car. This time could very well be different. Car and Driver has some exclusive photographs of what would appear to be a Corvette test mule with a mid-mounted engine. The car in question might look like a Holden SSV ute that's undergone some indelicate modification, but C/D editor Don Sherman assures that the bones of a C8 'Vette live within that crude bodywork. Sherman points to the closeness of the cabin to the front axle as clue number one of this car's mid-engine attitude, as well as the powertrain-sized space between the back of the seats and the rear axle. The roof and glasshouse are all clearly plucked from the current C7, and the gas tank filler positioned on the B-pillar is another huge clue. The buff book estimates that the mule points to a timeline for sale, even. Testing on this level could mean a mid-engined C8 ready for sale in as few as 20 months, or for the 2017 model year. Click over to Car and Driver to have a close look at this important set of spy photographs, as well as a rendering of what a finished C8 might ultimately look like

2018 Ford Expedition vs other big SUVs: How it compares on paper

With our Alex Kierstein rightly impressed in his first-drive review of the new 2018 Ford Expedition, we decided to dig a little deeper into the numbers, and we came up with the spreadsheet below to highlight how the new 2018 Expedition compares on paper to its main full-size SUV competitors: the 2018 Chevy Tahoe and Suburban (and therefore the 2018 GMC Yukon), 2018 Toyota Sequoia and 2018 Nissan Armada. We also threw in the new, even bigger 2018 Chevrolet Traverse since, as you'll see, its massive dimensions should put it on the radar for anyone who needs loads of passenger and cargo space but doesn't care as much about towing. A few notes about the chart above. First, the 6.2-liter V8 that's included with the new-for-2018 Tahoe RST trim level is the standard engine on the GMC Yukon Denali. You can apply most of the Tahoe's numbers to the entire Yukon and Yukon XL lineup. Second, though we highlighted categories where the Traverse led, we also highlighted the runner-up full-size SUV, since this was ultimately about that segment. Traverse numbers are broadly applicable to the new Buick Enclave. Related Video: Chevrolet Ford GMC Nissan Toyota SUV Comparison consumer ford expedition gmc yukon chevy traverse toyota sequoia nissan armada chevrolet tahoe ford expedition max