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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.

Is your new-car warranty good at the race track?

We've all heard the horror stories. Your buddy knows a girl that was dating a guy whose best friend's brother once broke his brand-new, recently purchased performance car while making runs at a drag strip or laps at a track day, and the manufacturer wouldn't cover the repair under warranty. True story? Urban legend? Complete crap? Yes, no, maybe. One thing's for sure: Automotive warranties have always come with caveats. In 1908, an ad in the Trenton Evening Times clearly stated: "All Ford Cars Guaranteed for One Year." Although it changed over time, by 1925 the Ford New Car Guarantee only covered 90 days on material and 30 days on labor, and it clearly stated that that there was "No guarantee whatever on Fan Belts, Glass, Bulbs, Wiring, Transmission, Bands, Hose Connections, Commutator Shells, Rollers, Spark Plugs or Gaskets." Whether or not Ol' Henry would pay to fix your Model T if you broke it shaving a tenth off your lap time at the local board track seems to be lost to history. We're guessing no. But what about today? Do new-car warranties in 2017 cover cars when they are driven on race tracks? We researched the warranties of 14 auto brands to find out, and the answer is yes, no, maybe, depending on the brand, in some cases the model, and whether or not your car is modified from stock. Acura has been out of the high-performance car game for a number of years, but jumps back into the party in 2017 with its hybrid-powered $173,000 NSX supercar. And Acura's warranty, as well as Honda's, clearly states that it does not cover "the use of the vehicle in competition or racing events." View 33 Photos So we asked Sage Marie, Senior Manager of Public Relations for Honda and Acura. "If the car is stock, the warranty covers it on a track just as it does on the street. No question," he told us. "However, if the car is modified, say with slick tires or other components that would put higher stresses on the vehicle's parts and systems, then we would have to investigate the circumstances further." Marie went on to say the same would be true for any Acura model or Honda vehicle, including the new 2017 Honda Civic Si. This became a common theme. Chevrolet actually started this practice with the fifth-generation Camaro on the high-performance ZL1 and Z/28 models.

Leaked GM document shows GMC Sierra I6 diesel is more powerful than F-150's

GM told us earlier this year that the 2019 GMC Sierra would be getting a 3.0-liter I6 diesel option, but it never mentioned power or fuel economy figures. Hold the phone though, because a leaked GM Canada document just showed up online that lists out the details we've been waiting for. Originally published by TFL Truck, the 3.0-liter oil-burner supposedly makes 282 horsepower and 450 pound-feet of torque. For those who are counting, that's more than the Ford F-150's 250 horsepower and 440 pound-feet from its 3.0-liter diesel. It soundly bests the 240 horsepower and 420 pound-feet of torque from Ram's 3.0-liter diesel as well. Fuel economy is another story, though. The promotional material states that it will get 28 mpg on the highway, which is 2 mpg short of the F-150's 30 mpg — mind you, it's only capable of that magical 30 mpg figure in rear-wheel drive form. There's another caveat here, too; these are numbers for Canada, so they're not exactly finalized EPA figures. However, we wouldn't expect drastic differences between the two when the American numbers come out. The leaked documents also state the diesel Sierra will be capable of towing 7,800 pounds. That number seems remarkably low when compared to the F-150, which can tow up to 11,400 pounds with its diesel. Extra power and torque would have us assume that GM could get even better numbers than Ford, so we're going to hold our final judgment for official word. A 10-speed automatic will do the shifting on the diesel, just like on the 6.2-liter V8. Since the Chevy Silverado is also expected to get this engine, we can assume the figures would be almost, if not identical, to those we see here. We recently drove the 2019 Sierra and Silverado without the diesel engines, so go check those reviews out if you'd like to know more of our thoughts on the redesigned GM trucks. Related video: