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This map reveals the cleanest vehicles based on location

Naysayers love to point out how dirty the electricity grid mix is when it comes to charging electric vehicles. Curmudgeons are eager to jump into any conversation about EVs to enlighten the lucky listeners about how plug-in cars contribute to pollution, sometimes even throwing in a dash of climate-change denial for good measure. (Thanks, buddy. Pray, tell me more about the plight of oppressed SUV owners.) Unless someone buys an EV just because they think they're cool (which, yeah, they often are), they probably have at least a passable understanding of their environmental pros and cons. As many EV owners are already aware, location has a lot to do with any particular plug-in car's carbon footprint. Still, there's always more to know, and knowledge is not a bad thing, especially if one uses it to do the right thing. That's why this handy-dandy map from Carnegie Mellon University is so interesting. CMU researchers have compiled information about the lifecycle greenhouse gas emissions of various EVs based on where they're charged, as compared to gasoline-powered vehicles. The researchers looked at the Nissan Leaf, Chevrolet Volt, and Prius Plug-In Hybrid versus the gasoline-dependent Toyota Prius hybrid and the stop-start-equipped Mazda3 with i-ELOOP and compared grams of CO2 emitted per mile. CMU takes into account the grid mix, ambient temperature, and driving patterns. CMU takes into account the grid mix based on county, as well as ambient temperature and driving patterns in terms of miles traveled on the highway or in the city. For instance, if you drive a Nissan Leaf in urban areas of California, Texas, or Florida, your carbon footprint is lower than it would be if you were driving a standard Toyota Prius. However, if you charge your Leaf in the Midwest or the South, for the most part, you've got a larger carbon footprint than the Prius. If you live in the rural Midwest, you'd probably even be better off driving a Mazda3. Throughout the country, the Chevrolet Volt has a larger carbon footprint than the Toyota Prius, but a smaller one than the Mazda3 in a lot of urban counties in the US. The Prius and Prius Plug-In are relatively equal across the US. Having trouble keeping it straight? That's not surprising. The comparisons between plug-in and gasoline vehicles are much more nuanced than the loudest voices usually let on.

8 cars we're most looking forward to driving in 2015

Now that 2014 is officially in the books, it's time to look ahead. And following our list of the cars we liked best last year, we're now setting our sights at the hot new metal that's coming our way in 2015. Some of these, we've already seen. And some are still set to debut during the 2015 auto show season. But these are the machines that keep us going – the things on the horizon that we're particularly stoked to drive, and drive hard. Jeep Renegade Not the Chevrolet Corvette Z06. Not the Ford Mustang GT350. Not the new John Cooper Works Mini. Nope, I'm looking forward to the adorable, trail-rated Jeep Renegade. And that's because I really, really, really like our long-term Jeep Cherokee Trailhawk. I do not, however, care too much for the Cherokee's looks, and I really don't like its $38,059 price tag. The Renegade Trailhawk, meanwhile, promises much of the same rough-and-tumble character as its big brother, but at what we expect will be a more reasonable price (I'm personally wagering on the baby Jeep's off-road model starting at no more than $23,000). With a 2.4-liter four-cylinder and a nine-speed automatic, it should also be a bit easier to fill than the V6-powered Cherokee. Also, I can't help but love the way the Renegade looks. It's like someone took a Wrangler, squished it by 50 percent and then handed it off to George Clinton for a healthy dose of funk. The interior, with its bright, expressive trims and color schemes should also be a really nice place to spend some time. I'll be attending the Renegade's launch later this month, so I'll have a much shorter wait than my colleagues. Here's hoping the baby Jeep lives up to my expectations. – Brandon Turkus Associate Editor Mazda MX-5 Miata Here's an uncomfortable truth: I'd rather spend a day driving a properly sorted Mazda MX-5 Miata of any generation on a winding road than I would nearly any other vehicle, regardless of power, price or prestige. It's not just that I prize top-down driving and enjoy the Miata's small size because it gives me more road to play with. I just find there's more motoring joy to be had with high-fidelity handling and an uncorrupted car-to-driver communication loop than I do with face-distorting power or grip – let alone valet-stand gravitas. But perhaps most of all, I love Miatas because they can deliver that level of feedback and driver reward at modest speeds that won't put the locals on edge or endanger lives – you can use more of the car more of the time.

GM patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging