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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.

One-off 2022 GMC Jimmy shows the convertible SUV that could have been

GMC is seemingly content to let the sixth-generation Ford Bronco take on the Jeep Wrangler on its own. The company left this segment of the market decades ago, but an Arkansas-based builder named Flat Out Autos is bringing the Jimmy back for the 2022 SEMA show. The modern-day Jimmy largely mirrors the Sierra 1500 that it's based on from the tip of the front bumper to the b-pillars. Beyond that, Flat Out Autos added redesigned quarter panels, removed the partition between the cargo box and the cabin, and installed rear seats. It also developed a removable, body-colored hardtop that brings the truck's silhouette in line with the second-generation Jimmy's. Out back, the versatile MultiPro tailgate remains, and the Jimmy keeps the Sierra's rear bumper with a step integrated into each corner. All told, the conversion looks surprisingly good. We bet GMC could sell a lot of these if it decided to jump back into the segment. The interior is mostly Sierra fare, though the front seats tilt forward and carpet lines the cargo box and the inner part of the tailgate. Flat Out Autos hasn't released technical details, so there's no word on what the Jimmy is powered by. More details will presumably be announced in the weeks leading up to the 2022 SEMA show, which opens on November 1, and Flat Out Autos plans to build 25 units.

2017 GMC Acadia comes into focus

The future slate of crossovers from General Motors reportedly ride on the company's new, scalable Chi platform. With short- or long-wheelbase configurations possible, the chassis conceivably allows the automaker to be more adaptable in the configuration of its CUVs. Cadillac already appears to be testing Chi for the luxury brand's future SRX/XT5, and here it is again under heavy camouflage underpinning the next GMC Acadia. Unfortunately, the Acadia is so well concealed here that it's extremely difficult to pick out any of the styling changes, though the squared-off fenders and faint GMC logo peaking through the tape on the front wheels reveal what this vehicle is. Up front, the grille appears to sit somewhat lower than the current model, and the vertical LED running lights are easy to pick out. The orientation of the taillights through the camo suggests wraparound units not too dissimilar from the current Acadia (or is that Saturn Outlook?). The next-gen Acadia is expected to debut in 2016 as a 2017 model year vehicle. The powertrain options may include the current 3.6-liter V6, a four-cylinder and possibly even a turbo V6, and GM's new nine-speed automatic might also be for offer. With a year before the reveal, take a look at these photos for a first look. Featured Gallery GMC Acadia Spy Shots View 12 Photos Image Credit: KGP Photography Design/Style Spy Photos GMC Crossover gmc acadia