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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 Defense shows Hummer EV-based military truck concept

GM Defense wants to convince the U.S. military that it has even more of what the military needs. During this week's Modern Day Marine 2023 exposition in Washington, D.C., GM Defense showed a new tactical vehicle concept based on the GMC Hummer EV platform. Called the Electric Military Concept Vehicle (eMCV), it uses the same Ultium platform and drivetrain as the retail Hummer EV. That means a 200-kWh battery (usable) powering three motors making 1,000 horsepower, with the two motors in back capable of torque vectoring, the single motor in front fitted with a locking diff. Upgrades over the dealership version include Fox shocks working larger 37-inch tires and heavy-duty brakes. The redrawn front and rear bumpers improve approach and departure angles. The tube chassis and lack of body panels would shed some of the Hummer's prodigious weight, nevertheless, range is reduced as a result of the other mods that reduce aerodynamic efficiency. Among said mods to the six-seater is a 46-inch gun ring and a swing side-arm mount when it's time to clock in. The estimated range drops to 300 miles from the 329 on the retail Hummer EV. Being mostly electric – more on that in a moment – the eMCV has features Silent Drive and Silent Watch driving modes could get fighters on-station with minimal noise.Plugged into a fast charger capable of 350 kilowatts, GM Defense says 12 minutes gets 100 miles of range. But when silence isn't a necessary factor, this is a series hybrid. GM Defense added a 12-kW diesel generator that can provide "limited charging and propulsion," which could also help charge "mission-critical equipment." A while back, the Army purchased a commercial Hummer EV for evaluation. The military didn't request this new concept, a GM Defense spokesperson telling Defense News it was built as a sign of potential. "We're trying to showcase what is in the realm of the possible just so we can get the discussion going and help shape [the military's] future requirements," the spokesperson said. "They get to see the different sizes and how to customize it, the different options." The eMCV sat on the trade show floor next to GM Defense's All-Electric Military Concept Vehicle, a Chevy Colorado-based Infantry Squad Vehicle (ISV) powered by a 60-kWh battery juicing an e-crate motor with 200 hp and 266 pound-feet of torque. The eISV was also built as a demonstrator without military input.

Canada opens probe into 250,000 GM pickups, SUVs over brake performance

Transport Canada, the auto safety regulator, has opened a probe into braking issues in nearly 250,000 General Motors full-size pickups and SUVs after U.S. officials launched a similar probe last year, the agency said on its website. The U.S. National Highway Traffic Safety Administration (NHTSA) in November into 2.73 million U.S. 2014-2016 model year SUVs and pickups after receiving 487 reports of hard brake pedal effort accompanied by extended stopping distance that were attributed to deterioration of the engine-driven brake assist vacuum pump. Transport Canada's probe covers 249,700 2015 through 2017 model year vehicles including the Cadillac Escalade, Chevrolet Suburban, Chevrolet Tahoe and GMC Yukon as well as 2014-2017 Chevrolet Silverado LD and GMC Sierra LD vehicles. The U.S. agency said it had reports of nine incidents of vehicles incurring damage as a result of colliding with another vehicle or fixed object at low speeds and reports of two injuries. NHTSA said if the pump fails to operate, the amount of brake power assist can be significantly reduced, extending vehicle stopping distance. The NHTSA sent GM an information request in a Feb. 7 letter. A GM spokesman said he had no update on the investigation. Reporting by David Shepardson; editing by Jonathan Oatis