2000 Gmc Savana 1500 Sle Standard Passenger Van 3-door 5.7l 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

'Killing a Duramax' Gale Banks YouTube series methodically tunes a diesel to death

Learning or perfecting a skill by watching YouTube videos is known as attending YouTube University. GM Authority picked up on one of the video site's more fascinating courses, hosted by Gale Banks; in a fair world, he should be referred to as Professor Banks when it comes to diesel engines and truck tuning. A few months after GM introduced the updated L5P 6.6-liter Duramax diesel V8 in the 2020 Chevrolet Silverado HD and GMC Sierra HD that ships with 454 horsepower and 910 pound-feet of torque, Banks decided he wanted to methodically tune the engine to death. The purpose of the resulting series, called "Killing a Duramax," is to push more power out of the engine in order to discover which parts break and when — or, as Banks puts it, force-feed the Duramax "until the crank hits the street and the heads hit the hood." With that knowledge, Banks can figure out all the weak points on his way to building what he calls a "Superturbo," that being a supercharged, twin-turbo race engine with more than 1,000 hp. What makes the series fascinating is Banks' knowledge, paired with the company's comprehensive iDash engine monitoring system that keeps tabs on a glut of parameters every step of the way. So for instance, you get Banks explaining the differences between inches of mercury and barometric pressure, how those are different from the water content of the air measured in grains, then showing those readouts on the iDash, then explaining in detail how they affect the air density in the Duramax system. The stock Borg-Warner variable turbo gets a lot of airtime — Banks accuses it of being "out to lunch" because he feels it's the weakest link on the engine. That turns into a turbo teardown and a deep explanation of performance pitfalls, such as when air pressure on the turbine begins to diverge from the boost pressure coming from the compressor. Banks says he can keep close tabs on where power's coming from, because the iDash monitors the horsepower contribution provided by the ambient air, the turbo, and the intercooler separately. The major changes so far are a stouter Precision 7675 turbo and TurboSmart wastegate (episode 5), a twin intake (episode 6), a custom liquid-cooled intercooler from a marine engine, a new GM oil cooler and synthetic oil (episode 10), and new injectors (episode 11).

2018 GMC Acadia with 'Christmas Aero' modification gets in the wind tunnel

Tis the season of "Big" - big cheer, big parties, big bowls of eggnog, big decorations, and when it comes to your family hauler, big drag. Festive drivers who festoon their crossovers, minivans, and SUVs with wreaths, Rudolph noses, fuzzy antlers, and rooftop Christmas trees undo the years of work that car engineers devote to fractional gains in fuel economy. To put numbers to such fuel-guzzling madness, GMC started with a 2018 Acadia, optioned it with the Xmas Aero Package - both Standard and Plus versions - put it in Lockheed-Martin's wind tunnel. The resulting dip in fuel economy results probably won't surprise anyone who's used a roof rack - or, for that matter, their car's air conditioning. However, it might surprise you to find out which seemingly substantial decoration had no effect, and which seemingly innocuous decoration was about twice as bad as running the A/C on its Mr. Freeze setting. Check out the brief video above for the results. And consider placement of that bow carefully.