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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.

Submit your questions for Autoblog Podcast #316 LIVE!

We record Autoblog Podcast #316 tonight, and you can drop us your questions and comments regarding the rest of the week's news via our Q&A module below. Subscribe to the Autoblog Podcast in iTunes if you haven't already done so, and if you want to take it all in live, tune in to our UStream (audio only) channel at 10:00 PM Eastern tonight.
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Nissan Leaf sets new November sales record, Chevy Volt drops again

When you talk to people in the plug-in vehicle industry, one theme you hear repeatedly is that the more plug-in cars that are out there, the better things are for everyone. One reason is that more EVs build a need for more public chargers, and more chargers mean more people see that plugging in is feasible. But there's still something to be said for old-fashioned competition, and in the sales race between the two long-running plug-in vehicles in the US, the Nissan Leaf is resoundingly beating the Chevy Volt for 2014. In fact, it won't be long before the EV's cumulative sales top the PHEV's. But that's a topic for another month. For now, we have the sales results from November. Unsurprisingly, Nissan set another monthly record (that is, the best Leaf sales in any November, the 22nd time in a row we've seen a monthly record) with 2,687 sales last month. That's up 34 percent over last November and up 35 percent year-to-date. Toby Perry, Nissan's director of electric vehicle marketing, said in a statement that, "Our 'Kick Gas' ad campaign and 'No Charge to Charge' launch in Chicago and Atlanta drove an increase in November Leaf sales. Even with gas prices falling across the country, consumers appreciate that the cost of driving a Nissan Leaf is still a fraction of that of a gas-powered car." Over on the Chevy side of the ledger, there were 1,336 Volt sales last month, down 30.4 percent from the 1,920 sold in November 2013. So far this year, Volt sales are down 16.4 percent and Chevy has sold 17,315 Volts in 2014. As we said last month, the Volt slump might be due to people waiting on the new version to make an appearance at the Detroit Auto Show next month before going on sale in the second half of 2015. So far in 2014, Nissan has sold 27,098 Leafs. Look for our detailed post of US green car sales in the near future. Until then, please discuss last month's Leaf and Volt sale in the comments, below. News Source: Nissan, General Motors Green Chevrolet Nissan Electric Hybrid PHEV ev sales hybrid sales