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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 Recalling Another 2.7 Million Vehicles In Five Separate Campaigns

The recalls keep rolling in from General Motors, evidently keen to avoid repeating the mistakes of the ignition-switch debacle and clean house. This time they're all coming at once, with five separate recalls announced together covering approximately 2.7 million vehicles. The largest of the five actions involves over 2.4 million units of the previous-generation Chevrolet Malibu and Malibu Maxx, Pontiac G6 and Saturn Aura in order to fix brake light wiring harness, which have been found to be susceptible to corrosion. The recall is separate from the 56k Aura sedans which GM recently recalled over faulty shift cables, not to mention the previous massive recall of 1.3 million vehicles – some of them the same models – but appears to have resulted from the National Highway Traffic Safety Administration investigation that started with the G6 almost a year ago. The second-largest campaign involves the 2014 Chevy Malibu, specifically those fitted with GM's 2.5-liter engine and stop/start system, approximately 140,000 examples of which has been found to have problematic brakes. The issue does not appear to be connected to the recall of 8k Malibu and Buick LaCrosse sedans (also involving brake woes) which we reported upon last week. Four crashes have been reported in such models, but GM admits it's not yet clear if the problem was a contributing factor in the accidents. A further 112k Corvette models from the 2005-2007 model years are being called in for problems with their low-beam headlamps resulting from a flexing relay control circuit wire that's not meant to bend. GM says it is "aware of several hundred complaints" about this issue, but notes that there have been no reports of related accidents. In addition, over 19k examples of Cadillac CTS from the 2013 and 2014 model years are being recalled over windshield wipers that might not work after a jump start. Finally, GM is also bringing in 477 examples of its 2014 Chevy Silverado, Tahoe and GMC Sierra (though not the Yukon) to fix a problem with a tie rod in its steering rack. As ever, all recall repairs will be performed free of charge, and GM is now estimating that recall-related actions this quarter will result in an estimated $200-million charge against its second-quarter earnings. Read the full announcement from GM below for further details.

Autoblog Podcast #326

Easter Jeep Safari concepts, Shelby 1000, 2014 Cadillac CTS and Mercedes CLA45 AMG leaks
Episode #326 of the Autoblog Podcast is here, and this week, Dan Roth and Zach Bowman talk about this year's Easter Jeep Safari concepts, the 1,200-horsepower Shelby 1000 and leaked images of the 2014 Cadillac CTS and Mercedes-Benz CLA45 AMG. We wrap with your questions and emails, and for those of you who hung with us live on our UStream channel, thanks for taking the time. Keep reading for our Q&A module for you to scroll through and follow along, too. Thanks for listening!
Autoblog Podcast #326: