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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 faces possible class action lawsuit over 8-speed transmission

General Motors has been hit with a class-action lawsuit from owners who allege the eight-speed automatic transmission found in several rear-wheel-drive Chevrolet, Cadillac and GMC models between the 2015 and 2019 model years has a defect that causes the vehicles to hesitate and jerk when accelerating or slowing down. The lawsuit was posted to ClassAction.org and spotted by GM Authority. Problems with GM's Hydra-Matic 8L90 and 8L45 transmissions have been well-documented on Internet forums and via complaints filed with the National Highway Traffic Safety Administration, with many reporting damage to their vehicles. The lawsuit was first filed in December in U.S. District Court for the Southern District of Florida but appears to have been transferred recently to New York. Autoblog sought comment from Theodore Leopold, the lead attorney for the plaintiffs. "These transmissions have a common defect," the complaint reads. "Drivers attempting to accelerate or decelerate their cars feel a hesitation, followed by a significant shake, shudder, jerk, clunk, or 'hard shift' when the vehicle's automatic transmission changes gears." The problem also occurs when the vehicles accelerate in a single gear, without shifting, the plaintiffs allege. "Drivers have reported that the shift is sometimes so violent, they feel as though they have been hit by another vehicle." The problem is believed to center on the transmission, torque converter or both. The complaint says it causes undue friction, causing hydraulic systems and gears to function improperly and sometimes leaves metal shavings throughout the transmission, leading to costly repairs and replacement of parts or the entire transmission. It says GM has known about the problems since shortly after it introduced the transmissions, and has issued 13 technical service bulletins, none of which have resolved the problem. GM declined to comment on the lawsuit. The plaintiffs say GM should have warned consumers about the issues and covered repairs under each vehicle's three-year/36,000-mile bumper-to-bumper warranty. They're seeking statewide classes in at least six states: California, Florida, Illinois, New York, Oklahoma and Texas.

Cadillac issues stop sale on ATS to recall 82k units

Cadillac is issuing a recall on 82,620 examples of the 2013-2016 ATS worldwide to fix a compliance issue with the sunroof controls. Until a service bulletin goes out to take care of things, there's also a stop sale on the luxury compact in the United States, The Detroit News reports. Of the affected models, 63,665 are in the US, according to a statement sent to Autoblog, and 7,922 of them are in Canada. The problem is actually the same issue as a recall on nearly 59,000 examples of the 2013-2015 ATS in the US in February. In them, the controls for the tilt and slide of the roof aren't recessed enough to meet government standards for the force necessary to operate the buttons. The Feds believe that someone could accidentally activate the auto-close and potentially be at risk. At the time, Cadillac dealers installed a new trim plate to add the needed clearance. In the latest update, the company is adding the 2016 model year, and according to The Detroit News, 70 percent of the cars from the original campaign also need another new trim plate. Unsurprisingly for such a minor defect, there are no known crashes, injuries, fatalities, or customer complaints related to this issue, according to the announcement by General Motors. Cadillac ATS Statement: General Motors is recalling 63,665 Cadillac ATS sedans in the United States from the 2013-2016 model years because the power-operated roof panel systems on these vehicles will auto-close when the non-recessed portion of the "Slide" or "Tilt" switches are pressed and the roof panel is open. Because these switches are not fully recessed, they can be actuated with less force than required to comply with applicable federal standards. GM knows of no crashes, injuries or fatalities related to this issue and has received no customer complaints. The total population of the recall including Canada, Mexico and exports is 82,620. Transport Canada Recall # 2015322 Recall Date 2015/07/21 Notification Type Compliance Mfr System Electrical Manufacturer Recall Number 15568 Units Affected The number of vehicles or components affected by the recall. 7,922 Category Car Recall Details Certain vehicles equipped with power-operated sunroof system may fail to conform to Canada Motor Vehicle Safety Standard (CMVSS) 118 - Power-Operated Window, Partition and Roof Panel Systems.