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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.

What the electric Hummer's size and weight means for its efficiency

The 2022 GMC Hummer EV Edition 1. Tim Levin/Insider If you think driving a pint-sized Nissan Leaf is as good for the planet as driving a huge electric Hummer, think again.  The GMC Hummer EV uses significantly more electricity than other EVs, meaning it produces more pollution upstream.  The electric Hummer weighs 9,000 pounds and its battery weighs as much as a Honda Civic. The new electric Hummer rolls through town without a deafening engine rumble or a cloud of toxic fumes, but it doesn't exactly tread lightly.  The colossal truck weighs an astonishing 9,000 pounds. (Think two Toyota Tacomas, three Honda Civics, or 24 Shaquille O'Neals.) Moreover, the GMC Hummer EV is in many ways a supersized gas guzzler for a new era. It repackages many of the same flaws of hulking SUVs and trucks of years past — and proves not all zero-emission cars are created equal. EVs can be energy guzzlers too On the whole, electric cars use less energy than gas-powered ones. But they aren't all equally efficient.  No surprise here: The Hummer needs more electricity than any other EV on the market to move its elephantine frame. The Environmental Protection Agency rates the pickup at 47 MPGe (miles per gallon of gasoline-equivalent). For comparison, the Tesla Model 3 sedan is nearly three times as efficient, earning a rating of 132 MPGe. The Ford F-150 Lightning, another electric truck, gets 70 MPGe.  This has real consequences: Since the US gets 61% of its energy from oil, coal, and natural gas, the more electricity a car needs, the more pollution it creates upstream.  As the Union of Concerned Scientists put it: "Both EV cars and trucks are much cleaner than their gasoline counterparts, but electric trucks are responsible for more global warming emissions than electric cars simply because trucks are larger and heavier."  The 2022 GMC Hummer EV Edition 1. Tim Levin/Insider The Hummer EV is also resource-intensive to manufacture, requiring a ginormous (and weighty) battery to give people the 300-plus miles of range they desire. You could produce three Chevrolet Bolts with the same battery cells consumed by one Hummer.

GM announces 6 recalls covering nearly 720k cars

General Motors has announced yet another sprawling recall campaign, with six separate elements covering 717,950 vehicles on US roads. At this point in 2014, it's starting to seem like there are more days with a GM recall than without. Perhaps most troubling about this latest volley, though, is that every vehicle is from the past few years, indicating that GM's quality woes may not be limited to pre-bankruptcy vehicles.
The largest element of this latest campaign covers 414,333 units, and includes the 2011 to 2012 Chevrolet Camaro, 2010 to 2012 Chevy Equinox, GMC Terrain and Cadillac SRX and the 2011 to 2012 Buick Regal and LaCrosse. Only vehicles with powered, height-adjustable seats are covered. In these particular cars and crossovers, the bolt that secures the height adjuster actuator may loosen of its own accord and in some cases fall out completely. If this happens, the seats will be able to move both up and down. GM claims the vehicles are safe to drive, provided drivers don't vertically adjust their seats. This particular issue has caused one crash and three injuries.
The largest element of this latest campaign covers 414,333 units, including the Chevrolet Camaro and Equinox, GMC Terrain, Cadillac SRX and the Buick Regal and LaCrosse.