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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.

Why an independent rear suspension for GM's new, full-sized SUVs wasn't easy

A Motor Trend report last month laid out how Cadillac's 4.2-lier twin-turbo Blackwing V8 could be an orphan due to cost concerns in the GM empire. Last-minute chassis changes to Cadillac's new sedans and XT6 crossover led to engine bays that couldn't fit the Blackwing. On the SUV side, according to the report, the new independent rear suspension for big people haulers cost so much to implement that GM ruled out reworking the Escalade to accept the Blackwing. At least one commenter rightly asked how could a suspension swallow that much money. A new piece in Motor Trend has the answer. The excellent Alissa Priddle spoke to Tim Herrick, GM's executive chief engineer for full-size trucks, about why the clean-sheet IRS cost "multimillions of dollars."  First, GM would need to build a new body shop at the Arlington, Texas plant that assembles the automaker's big SUVs to stamp the numerous wholly new parts and panels accommodating an IRS. Then GM would need to design and pay for a new assembly process. On top of those up-front costs, there was the incremental cost of the four-link IRS components being more expensive than those in the trucks' former leaf-sprung solid axles. Herrick endured so many rejections for so long that he remembers the date and time when he got approval for the new unit. He said it came down to a meeting where he told a higher-up, "I'll make you a deal: If we get to the reveal, or if we launch this and you think this was a dumb idea, I'll hand you my badge and let you walk me out." Head to Motor Trend to read the full story. Based on Herrick being on stage to help present the new SUVs to the press, and on our First Ride in the new Chevrolet Tahoe and Suburban at GM's Milford Proving Grounds, it appears this will have a happy ending for all involved. Furthermore, since Herrick worked on the T1 platform that supports the big SUVs as well as the light- and heavy-duty pickups, he understood the demands on the commercial side, too. That could be why when Roadshow asked Tim Asoklis, chief engineer of the Tahoe and Suburban, if the new IRS could endure life in the Chevrolet Silverado and GMC Sierra, Asoklis answered, "Oh, absolutely." Related Video:    

Autoblog Minute: VW finds CO2 'irregularities', Takata dropped by automakers, SEMA recap

Volkswagen's diesel emissions scandal gets a new wrinkle, US regulators hit Takata Corporation with a substantial fine, and we head to Las Vegas for a look at tuner paradise at the 2015 SEMA show. Autoblog senior editor Greg Migliore reports on this edition of Autoblog Minute Weekly Recap. Show full video transcript text [00:00:00] Volkswagen's diesel emissions scandal gets a new wrinkle. US regulators issue a significant fine to Takata Corporation. And we take a peek inside tuner paradise at the 2015 SEMA show. I'm senior editor Greg Migliore and this is your Autoblog Minute Weekly Recap. The VW diesel emissions scandal, first brought to light in September, gets a new wrinkle, as an internal investigation by the German automaker revealed [00:00:30] irregularities in CO2 emissions that could affect approximately 800,000 vehicles. VW estimates the issue could pose a 2-billion euro economic risk. VW claims that most of the vehicles affected have diesel engines, but industry analysts say a 1.4-liter gas engine is also affected. VW says that fuel consumption figures were set too low during the CO2 certification process. During all of this, sales of some diesel-powered Volkswagen, Audi, and Porsche models [00:01:00] have been halted. Takata Corporation is back in the news in connection with its deadly airbag scandal. Federal regulators fined Takata $70 million. If the parts supplier does not comply, the fine could balloon to $200 million. Takata was also dropped this week by its biggest customer, Honda. And now, Toyota and Mazda will be following Honda's lead in dropping Takata. We're also hearing that Mitsubishi and Subaru are considering a switch in air-bag inflator suppliers. SEMA 2015 [00:01:30] came and went. We saw offerings from Mopar, like the AWD Challenger concept. Honda unveiled a Ridgeline that it will race at the Baja 1000, which gives us a hint at what future production model could look like. The celebrity presence was also felt in Vegas as it always is. Kid Rock brought a Duramax Diesel Chevy Silverado, and Acura restored and presented Ludacris with his now famous 1993 Acura Legend. Those are the highlights from the week that was. Be sure to come back on Saturday for my full recap, [00:02:00] where I'll have some added insight into Hyundai's foray into the luxury sector. For Autoblog, I'm Greg Migliore. Autoblog Minute is a short-form video news series reporting on all things automotive.