2008 Gmc Sierra 2500hd 2500 Hd. Duramax Turbo Diesl. Allison Trans. on 2040-cars

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These are the 'Greenest' and 'Meanest' cars in 2015

As has become tradition, the American Council for an Energy-Efficient Economy (ACEEE) has come up with a ranking of what it refers to as the "greenest" cars of 2015, and, by way of contrast, a list of the so-called "meanest" cars, so those who value eco-friendliness over all else can choose which vehicles they should or should not consider buying. As you may expect, electric cars make up the majority of the greenest cars on the list, but, perhaps surprisingly to many, the Tesla Model S didn't make the cut. It's worth noting, too, that where the electricity an owner uses to charge their electric vehicle has a big impact on its overall environmental impact. "A car that is charged using electricity generated from natural gas or renewables is going to have significantly less impact on the environment than one charged on a coal-heavy grid," says ACEEE lead vehicle analyst Shruti Vaidyanathan. The ACEEE's list for 2015 looks very different than it did in 2014. It's an interesting collection, though – and we're sure this goes without saying, really – we'd recommend doing a bit more research into each vehicle and how it might fit into your daily life before making any purchase decisions. Click here to see the ACEEE's list of the Greenest and Meanest vehicles sold in the United States in 2015. Green Bugatti Chevrolet Fiat GM GMC Mercedes-Benz Nissan RAM smart Toyota greenest greenest cars

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.

2022 GMC Hummer EV shows off accessories ahead of SEMA

As is the case with nearly every new off-roader on the market, the 2022 GMC Hummer EV will have a bunch of accessories available for personalizing the big electric pickup truck. In fact, GMC says that the total number of add-ons is close to 200. But for the SEMA show, it's sharing just a few of what it says are the more interesting accessories. Quite a few of these parts will take you a long way to turning the Hummer EV into an overlander. The most obvious is the roof-top tent that utilizes mounts on the roof and the bed. It looks quite large and roomy. Naturally, auxiliary lighting is available, too, including a 50-inch roof light bar and two smaller spot lights that mount ahead of the A pillars. For storage, there's a nifty swing-out toolbox, shown in the gallery as more of a tackle box, plus a battery-powered cooler and a bed-mount for a full-size spare tire. There's also a more traditional bed extender and simple bed rail-mounted rack. And just for fun, you can get a Kicker audio sound system built into the MultiPro tailgate to listen to your music. Not all the accessories are about utility, though. There are some visual enhancements such as the red decals shown in the gallery. They match other decals and badges available, and they're offered in bronze, too. There are some branded puddle lights on offer as well. These should be available around when the Hummer EV pickup goes on sale next year. Pricing for each part will surely vary, though exact numbers haven't been announced. Related video: This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.