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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

GM drops diesel engines for 2020 Chevy Equinox and GMC Terrain crossovers

GM is officially discontinuing the diesel engine in the Chevy Equinox and GMC Terrain for the 2020 model year. The 1.6-liter turbodiesel was always an oddball of an engine in the compact crossover segment, and now the experiment has come to an end. The Car Connection initially reported the news, and a GMC spokesperson, Stuart Fowle, confirmed it to us this morning.  “A huge majority of our Terrain customers have opted for one of our two gas engines," says Fowle. We canÂ’t say this eventuality comes as a massive surprise, as we saw news from couple of months ago that GM was dropping all-wheel drive from the diesel-powered cars for 2020. Low demand was cited as the reason for that cull, and itÂ’s the same for the little GM crossovers this time around, too. These vehicles were the only ones powered with a diesel engine in their class, but thatÂ’s going to be changing. Just as GM is going away from the diesel, Mazda is finally bringing its diesel to market in the CX-5. YouÂ’ll only be able to get that engine in the most expensive ($42,045) trim level, combined with all-wheel drive, though. The cheapest Equinox diesel starts at a comparably low $30,795. ThatÂ’s a $2,400 upcharge over the base 1.5-liter turbo four-cylinder, and the value is questionable. Mileage is better, but diesel fuel is more expensive. Towing capability didnÂ’t increase over the base engineÂ’s 1,500-pound capacity, but the extra torque around town was nice. As diesels go in the U.S., this one was rather rough and noisy, possibly contributing to some turning their noses up after a test drive. Perhaps another reason for its demise was that the much quicker 2.0-liter turbo Equinox was only $100 more than the diesel. This engine offered significantly better towing at 3,500 pounds, too. You can read all about what we thought of the diesel in our first drive review here, but the 2019 model year is the last one if you had it on your shortlist. This article has been updated to indicate the source.

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