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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.

Weekly Recap: Lincoln Continental serves up the style, Cadillac CT6 delivers the substance in New York

Lincoln and Cadillac grabbed the spotlight this week at the New York Auto Show in a dramatic fashion that evoked the brands' glory days. America's two luxury carmakers went toe-to-toe with their glittering reveals and plans for ambitious expansion. Both were selling their technology, style and the promise of a better future. Cadillac vs. Lincoln. At the Javits Center, 2015 seemed a lot like 1956. Neither company was interested in drawing comparisons with the other, which is fair, and accurate. They're in vastly different places in terms of sales and the pace of their turnarounds, but they hope to reach the same eventual destination at the pinnacle of the luxury-car world. Lincoln used the element of surprise to great effect with the Continental concept. A production version is still at least a year away, and the company was vague on details. Officially, we don't even know if it is front- or rear-wheel drive, though speculation abounds. Who cares? The seats can be adjusted 30 ways! The Continental also showed off a bold chrome grille that will be the new face of Lincoln. The blue bomber also rolled on blinged-out 21-inch polished aluminum wheels, used a 3.0-liter EcoBoost engine and had huge LED head lights with "laser-assisted" high beams. All of this resulted in almost blinding attention. The concept drew rave reviews, stirred controversy with Bentley designers who argued Lincoln ripped them off, and most importantly, pointed a way forward for the newly determined brand that hopes to compete with Mercedes, BMW, Audi, Cadillac and Lexus. View 32 Photos Meanwhile, Cadillac showed the CT6, a finished product that will top its range and is loaded with the best and latest technologies General Motors has at its disposal. With production starting late this year, Cadillac had more specifics at the ready. Engines? Cadillac has a couple V6s and a turbo four for sure. It's working on a hybrid, and has considered a V-Series variant. It's based on a new rear-wheel-drive, aluminum-intensive chassis called Omega, features an advanced collision-mitigation system with automatic braking and has a cabin that's laden with "leathers, exotic woods and carbon fiber." It will be assembled at GM's Detroit-Hamtramck factory and goes on sale next year. At this point, Cadillac is more than willing to talk about every except for the price. The devil was not in the details for Cadillac, as evidenced by the CT6. But it wasn't for Lincoln either.

Is the skill of rev matching being lost to computers?

If the ability to drive a vehicle equipped with a manual gearbox is becoming a lost art, then the skill of being able to match revs on downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. The usefulness of rev matching in street driving is limited most of the time – aside from sounding cool and impressing your friends. But out on a race track or the occasional fast, windy road, its benefits are abundantly clear. While in motion, the engine speed and wheel speed of a vehicle with a manual transmission are kept in sync when the clutch is engaged (i.e. when the clutch pedal is not being pressed down). However, when changing gear, that mechanical link is severed briefly, and the synchronization between the motor and wheels is broken. When upshifting during acceleration, this isn't much of an issue, as there's typically not a huge disparity between engine speed and wheel speed as a car accelerates. Rev-matching downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. But when slowing down and downshifting – as you might do when approaching a corner at a high rate of speed – that gap of time caused by the disengagement of the clutch from the engine causes the revs to drop. Without bringing up the revs somehow to help the engine speed match the wheel speed in the gear you're about to use, you'll typically get a sudden jolt when re-engaging the clutch as physics brings everything back into sync. That jolt can be a big problem when you're moving along swiftly, causing instability or even a loss of traction, particularly in rear-wheel-drive cars. So the point of rev matching is to blip the throttle simultaneously as you downshift gears in order to bring the engine speed to a closer match with the wheel speed before you re-engage the clutch in that lower gear, in turn providing a much smoother downshift. When braking is thrown in, you get heel-toe downshifting, which involves some dexterity to use all three pedals at the same time with just two feet – clutch in, slow the car while revving, clutch out. However, even if you're aware of heel-toe technique and the basic elements of how to perform a rev match, perfecting it to the point of making it useful can be difficult.