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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

Leak reveals GM's 2017 heavy duty diesel trucks to get 910 lb-ft of torque [UPDATE]

UPDATE: Chevrolet officially announced specs for the 2017 Silverado HD and the rumors were true. The truck's new Duramax 6.6-liter turbo-diesel V8 puts out 445 horsepower and 910 pound-feet of torque. Chevrolet says the new motor produces 19 percent more torque and 12 percent more horsepower, while producing 35 percent fewer emissions. Overall, the new engine is a big improvement over the current motor, which generates 397 horsepower and 765 pound-feet of torque. According to Truck Trend, GM's newest heavy duty pickup trucks will pick up quite a bit more power and torque. The publication spotted a recent GM Powertrain ordering catalog that had the engine specs for the 2017 model year and managed to get some screenshots before the catalog was taken down, and they can be viewed here. The screenshots revealed that the 6.6-liter turbodiesel V8 powering the Silverado and Sierra heavy duty models will boast 445 horsepower and 910 lb-ft of torque. This is a substantial gain over the current models' 397 horsepower and 765 lb-ft of torque, and as Truck Trend points out, it exceeds the Ford Super Duty line's horsepower output of 440, but comes short of the 925 lb-ft rating. Truck Trend credits part of this output gain to the new intake system GM will introduce on the 2017 heavy duties. The intake gets 60 percent of its air from a scoop on the hood, with the other 40 percent coming from behind one of the front fenders. GM doesn't reveal horsepower figures in the press release about the scoop, but it does say the cooler air helps with maintaining the engine's output, and that the scoop does produce a ram-air affect, providing more air at speed. As we know, more air plus more fuel equals more power, but there's likely more to the power increase in this engine than only the intake. Related Video: News Source: Truck Trend via MSN Chevrolet GM GMC Truck Diesel Vehicles

1983 Motorweek showdown pits Porsche 928S vs. Chevy Camaro Z28

Last month, Motor Trend threw the Camaro Z/28 and Porsche 911 GT3 into the bear pit and let them fight it out. Way back in 1983, MotorWeek had the same idea, comparing the Camaro Z/28 to the Porsche 928S. At the time, the Camaro was America's best selling sports coupe, the 928S was Porsche's top-of-the-line model that also had the highest top speed of any car sold here. And the price differential was even more stark then: $13,600 for the Camaro, $45,000 for the Porsche. That put the Z/28's cast-iron, 5.0-liter V8 with 190 horsepower and 240 pound-feet of torque against the all-aluminum 4.7-liter V8 with 234 hp and 263 lb-ft in the 928S. Even with that and the Camaro being 14 inches longer than the Porsche, the American was a surprising 40 pounds lighter than the German. The show took them to Summit Point Raceway in West Virginia to see how close a relative performance bargain could hang with a the German GT. Both had five-speed manual transmissions, but the high-speed corners and tight sections of Summit Point would test other handling variables, including the "bone-rattling" Camaro's solid rear axle and disc and drum brake setup vis-a-vis the four-wheel disc brakes and independent suspension on the "firm-but-smooth" Porsche. Paradoxically, the larger disparity 22 years ago resulted in a closer result. Check out the video to see how the Summit was won. News Source: MotorWeek via YouTube Chevrolet Porsche Coupe Luxury Performance Classics Videos chevy camaro z28 porsche 928 retro review