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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

Cadillac ATS to go racing in 2015 as CTS.V.R replacement

Cadillac has been racking up victories with the CTS.V.R in Pirelli World Challenge racing for two model generations now, including recent GT class championships in 2012 and 2013. However, even winning racers eventually have to retire, and it looks like the CTS may be taking a bow at the end of the season. In its place, Caddy is reportedly working on a new racecar based on the ATS Coupe, and it might even get to compete internationally.
According to Racer, Pratt & Miller Engineering is leading the development and is already lapping the ATS racecar in Michigan for testing. It reportedly drops the CTS' V8 in favor of a twin-turbocharged V6 powering the rear wheels. Since this is the same team behind the hugely successful Corvette Racing program and the current CTS.V.R, the latest car appears to be in good hands.
The new model would also adhere to GT3 rules, according to Racer, and that might signal a big change for Cadillac's motorsports program. It means that the ATS could be sold to teams in the numerous series around the world that accept these vehicles. That would broaden the luxury coupe's exposure and put it up against GT3 racecars from premium brands, like Bentley, Porsche and McLaren. If it wins, the change could be a marketing bonanza for the brand.

GM recalls 3.6 million vehicles for airbag-software problems

The Basics: General Motors is recalling 3.64 million vehicles across its lineup for an airbag-related issue. The recall covers the 2014-2015 Buick LaCrosse, Chevrolet SS, and Spark EV; 2014-2017 Chevrolet Corvette, Trax, Caprice PPV, Silverado 1500, Buick Encore, and GMC Sierra 1500; and 2015-2017 Chevrolet Tahoe, Suburban, Silverado HD, GMC Yukon, Yukon XL, Sierra HD, Cadillac Escalade, and Escalade ESV. The Problem: Affected vehicles have a sensing and diagnostic module that controls the airbags and seat-belt pretensioners. The software it uses has a defect that can prompt the module to run a diagnostic test under specific driving conditions, which will also deactivate the front airbags and pretensioners. This means that it would be possible for those safety systems to not activate in a crash, potentially leading to injury or death. Injuries/Deaths: General Motors began an investigation that led to the recall after a 2014 Silverado was involved in a crash in which the airbags did not deploy. No information was given as to injuries or deaths. The Fix: Owners can bring their vehicles to a local General Motors dealer where a software update will be installed to fix the issue. The fix will be free of charge. If you own one: General Motors will contact owners of affected cars, and owners can check whether their vehicles are affected by visiting entering their vehicle identification numbers at either the GM Owner Center website or the NHTSA website. Owners can then schedule a time to have the update installed. Related Video: