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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 Issues Four New Recalls For 90,000 Vehicles

One day after releasing an internal report that found a pattern of "incompetence and neglect" within the company, General Motors announced four more recalls that affect 89,126 vehicles. One of the recalls affects 31,520 vehicles that may contain a defect that could prevent airbags from deploying in a car accident. GM said it was aware of at least one crash in which a vehicle occupant sustained an injury because the airbags didn't deploy when they should have. The company said it was aware of other crashes that were similar in nature, but it is not yet known whether they're related to the condition, in which the shorting bar inside the driver's airbag may occasionally contact the airbag terminals. If the car and terminals are touching each other in a crash, the bags will not deploy. Vehicles from the 2012 model year are affected by the problem, and they include the Buick Verano, Chevrolet Camaro, Cruze and Sonic. GM has conducted two previous recalls for this condition involving 7,116 cars. GM is also recalling 57,512 models of the 2014 Chevrolet Silverado 1500, 2014 GMC Sierra 1500 and 2015 Silverado HD, Tahoe and Surburan, as well as the 2015 GMC Sierra HD, Yukon and Yukon XL models because their radio control modules may not work, and thus prevent certain audible safety warnings. Certain models of the 2013-2014 Chevrolet Spark and 2013 Buick Encore are being recalled for a different airbag problem, which could prevent airbags from deploying properly during a crash. And 33 2014 Chevrolet Corvettes are being recalled for yet another airbag problem, in which an internal short circuit could disable the airbags. So far in 2014, General Motors has issued 34 separate recalls that affect approximately 15.9 million vehicles – more than the company has sold in the past five years combined. GM Announces Four Recalls DETROIT – General Motors today announced three safety recalls and one non-compliance recall, all of which were reported to the NHTSA on Thursday, June 5, 2014. In all cases, customers will receive letters from GM letting them know when they can bring their vehicles into a dealership, where all repairs will be performed free of charge and courtesy transportation would be provided as needed.

'Killing a Duramax' Gale Banks YouTube series methodically tunes a diesel to death

Learning or perfecting a skill by watching YouTube videos is known as attending YouTube University. GM Authority picked up on one of the video site's more fascinating courses, hosted by Gale Banks; in a fair world, he should be referred to as Professor Banks when it comes to diesel engines and truck tuning. A few months after GM introduced the updated L5P 6.6-liter Duramax diesel V8 in the 2020 Chevrolet Silverado HD and GMC Sierra HD that ships with 454 horsepower and 910 pound-feet of torque, Banks decided he wanted to methodically tune the engine to death. The purpose of the resulting series, called "Killing a Duramax," is to push more power out of the engine in order to discover which parts break and when — or, as Banks puts it, force-feed the Duramax "until the crank hits the street and the heads hit the hood." With that knowledge, Banks can figure out all the weak points on his way to building what he calls a "Superturbo," that being a supercharged, twin-turbo race engine with more than 1,000 hp. What makes the series fascinating is Banks' knowledge, paired with the company's comprehensive iDash engine monitoring system that keeps tabs on a glut of parameters every step of the way. So for instance, you get Banks explaining the differences between inches of mercury and barometric pressure, how those are different from the water content of the air measured in grains, then showing those readouts on the iDash, then explaining in detail how they affect the air density in the Duramax system. The stock Borg-Warner variable turbo gets a lot of airtime — Banks accuses it of being "out to lunch" because he feels it's the weakest link on the engine. That turns into a turbo teardown and a deep explanation of performance pitfalls, such as when air pressure on the turbine begins to diverge from the boost pressure coming from the compressor. Banks says he can keep close tabs on where power's coming from, because the iDash monitors the horsepower contribution provided by the ambient air, the turbo, and the intercooler separately. The major changes so far are a stouter Precision 7675 turbo and TurboSmart wastegate (episode 5), a twin intake (episode 6), a custom liquid-cooled intercooler from a marine engine, a new GM oil cooler and synthetic oil (episode 10), and new injectors (episode 11).