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GM exploring ways to raise half-ton Duramax diesel tow rating

Lots of truck owners cheered when GM announced fuel economy numbers for the 2020 Chevrolet Silverado with the 3.0-liter Duramax diesel inline-six. Even after Ram let loose its EPA mileage ratings for the 2020 Ram 1500 EcoDiesel, the Chevy oil-burner still took the trophy. The victory was years in the making, GM engineers spending an entire four-year development cycle refining the LM2 Duramax to increase mileage. The tradeoff, as well all know by now, is towing; the Duramax in half-ton duty pulls a maximum 9,300 pounds in the Silverado. Rivals across town can do more, the Ford F-150 PowerStroke rated at 11,500, the Ram 1500 EcoDiesel game to pull 12,560. GM engineer John Barta told Muscle Cars & Trucks that more hauling chops could be on the way, explaining, "We’re actually looking at upgrading some of the materials around (the engine bay) to see if we can maybe raise our tow rating." Engine bay materials are at issue due to thermal complexities underhood. John Barta, GM's assistant chief engineer of diesel engine controls, said the Duramax's inline-six configuration allowed engineers to get emissions hardware like the combined selective catalytic reduction, diesel oxidation catalysts, and diesel particulate filter unit closer to the engine, where it heats up quicker, getting emissions down quicker. But that filter puts another heat source in those confines, enforcing a cap on the tow rating to keep the engine and other systems from overheating. "If you look under the hood," he said, "youÂ’ll see a significant amount of silver ‘moon tapeÂ’ around to make sure things arenÂ’t getting overheatedÂ… if we were to go up in higher towing, which we can, we start impacting the possibility of deteriorating some of the components.” There isn't much space for more grille, so swapping for a better grade of "moon tape" or a different kind of material could reduce engine bay heat, extracting a higher tow rating in the process.  It's important to note a point Barta's been making for months about the Duramax figures, though. "Even though itÂ’s nice to brag about big numbers, in reality, light duty customers are not towing that large with their trucks," and, "We do know that (95 percent) of our light duty customers donÂ’t tow over 9,000 pounds." On our First Drive of the 2020 Silverado diesel we called out the tow rating, but emphasized that the Chevy and GMC have more important challenges to overcome.

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

2015 Callaway Corvette Z06 gets new supercharger, adds $17K to starting price

Callaway's proud tradition of modifying Chevrolets is about to add a very significant chapter this weekend, as the company prepares to unveil a modified version of the 2015 Corvette Z06. The engine mods are simple, though we expect them to be very potent. That's because Chevy has replaced the factory supercharger with a new "GenThree" unit that's nearly a third larger than what's bolted on in Bowling Green. A new intercooler is also added, along with a new high-flow intake system. Beyond that, the changes are exclusively of the subtle cosmetic variety. There's new badging inside and out, as well as new engine covers, floormats and an underhood plaque. Naturally, there's documentation to verify the Callaway Z06's authenticity, and the comfort that comes with a three-year, 36,000-mile warranty. Callaway has priced the upgrade package at $16,995, in addition to the price of the stock Z06. While we're still waiting to hear official power figures, that seems like a reasonable asking price for what were wagering will be a major increase in power. The Callaway Z06 will debut this weekend at the National Corvette Museum's C7 Bash in Bowling Green, KY. Expect more details following the debut. Scroll down for the official press release. Related Video: 2015 Callaway Corvette Z06 to Debut at National Corvette Museum The 2015 Callaway Corvette Z06 will debut at the National Corvette Museum C7 Bash in Bowling Green, Kentucky, April 23 through April 25. Here's a sneak peek at the new package. Based on Chevrolet's track-proven Z06, Callaway engineers' no-compromise approach takes this Corvette to an astounding power level. While advertised Callaway horsepower and torque are pending final validation, the Callaway package adds Callaway's new GenThree supercharger system with 32% more displacement than the stock Z06 supercharger, improved manifold design and unique triple-element intercooling system. Callaway engineers recognize that a key contributor to maximizing power is reduction of inlet air temperature. By exposing the supercharger's large plenum area to outside ambient airflow, the design takes advantage of the significant charge air temperature reduction provided by convective cooling. The completely redesigned intercooling system also helps maintain nearly ambient charge air temperature with exceptionally low air restriction.