03 Tahoe Third Row Seat 8 Passenger Leather Moonroof on 2040-cars

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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.

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

2019 GMC Sierra revealed with CarbonPro bed and new diesel engine

It's only March, and it's already been one hell of a year for trucks. January's Detroit Auto Show saw the reveals of the 2019 Ram 1500, 2019 Ford Ranger and the 2019 Chevy Silverado. The Chicago Auto Show brought new versions of the Toyota Tacoma and Toyota Tundra TRD Pro. Today, we finally got our first look at the Silverado's twin, the 2019 GMC Sierra. The truck features new styling, a new diesel engine and — on the Sierra Denali — a carbon fiber bed. As with every new full-size truck, the Sierra is larger than the outgoing model in almost every dimension, though exact dimensions haven't been revealed. For reference, though, the Chevy Silverado's bed is 7-inches wider than before. The new Sierra grille is more upright than before and features new C-shaped lighting. The Denali gets LED headlights, tail lights and fog lights. Both SLT and Denali trims get unique 22-inch wheels. As we saw in spy photos, the Sierra's interior is mostly just a copy of the Silverado's with some chrome accents sprinkled throughout. If you like the current truck interiors, you'll be pleased with the new model. Those hoping for a wholesale change will be left wanting. The big improvements inside include a full-color heads-up display, trailer hitch assist apps and cameras, and the rear-camera mirror found in models like the Chevy Traverse and Cadillac CT6. Safety and convenience features include a surround-view camera, blind-spot monitoring, pedestrian detection and low-speed automatic braking. Like the Silverado, there's been a significant effort to cut weight in the new Sierra. The 2019 model loses as much as 360 pounds compared to the current truck. It uses aluminum for the doors, hood and tailgate. Steel is still used for the fenders, roof and standard cargo box. The Denali, however, gets the real surprise here. Available only on the top-tier trim, the bed box will be constructed of carbon fiber rather than steel, saving 62 pounds. Carbon fiber only replaces the steel inner panels and floor. GMC says the carbon fiber will also help scratch and corrosion resistance. SLT and Denali models also get a new MultiPro tailgate. This is unique to the Sierra and separate from the Silverado's power assist unit. A new feature that helps one get into and out of the bed using an assist handle. The tailgate step has a maximum weight capacity of 375 pounds. There multiple positions that allow customers to extend the bed, or drop the center vertically to gain easier access to the back.