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2020 GMC Acadia AT4 Review | A soft-roader in steel-toed boots

For carmakers today, the perfect lineup would be focused almost entirely on trucks and crossovers, favoring profitability at the expense of diversity. Just look at FCA’s Ram and Jeep showrooms. In the General Motors portfolio, that brand is GMC, with not a car to be found in its lineup and several body-on-frame offerings meant to take a serious beating. It should be a license to print money. But a lineup of trucks and SUVs isnÂ’t enough. Some folks want the rough-and-tumble edge of an off-road vehicle, albeit one that can still credibly serve duty in the school pickup line. Enter the AT4 trim level, an off-road package that spans the gap between the GMC's upscale professional image and the off-road oriented buyer. The 2020 GMC Acadia AT4 is the latest member of the family AT4 slots in between the mid-grade SLT and the range-topping Denali, but simply saying itÂ’s the second-most expensive Acadia variant isnÂ’t really doing it justice. If the SLT trim is understated, and the Denali trim opulent, the AT4 trim promises ruggedness and adventure – even if it canÂ’t deliver it.  The Acadia is definitely a soft-roader and AT4 doesnÂ’t do much to change that – itÂ’s effectively an appearance package. It adds a unique grille, 17-inch wheels and AT4 badges — all blacked out — plus a set of Continental TerrainContact A/T tires engineered to offer a comfortable ride while still enabling some off-pavement excursions. There are several unique interior treatments as well, including “AT4” embroidery on the seats, regardless of whether you go with the base upholstery or the upgraded perforated leather ($1,000) that was added to our test vehicle. Note that we didnÂ’t mention anything beyond the small wheels and meaty tires that would actually make the AT4 any better off pavement. ThereÂ’s no extra ground clearance (it remains a meager 7.2 inches), low range 4x4 system or suspension enhancement to be found here. This would be a departure from other GMC AT4 models, including the Sierra 1500 and upcoming 2021 Yukon, which get extra ground clearance, underbody protection and a rugged suspension, but it won't be an outlier. The similarly soft-roading Terrain AT4 has already been announced.  Yet, off-road models tend to get hammered with on-road handling and ride quality criticism and here's where the Acadia AT4 being more of an appearance package pays off.

2019 GMC Sierra carbon fiber bed: How it's made

FORT WAYNE, Ind. — The redesigned 2019 GMC Sierra has some pretty nifty features, and the one that has had the most attention is the MultiPro flipping and folding tailgate. But the Sierra also features the first-of-its-kind carbon fiber truck bed. It's interesting, of course, for its capabilities, such as being 62 pounds lighter than the all-steel box. It even adds more cargo volume since the material can be assembled and shaped differently from steel. As it turns out, the assembly process is cool, too, which we learned when GMC invited us to see the beds being made. Every GMC carbon fiber bed starts out as perfectly flat sheets of thermoplastic carbon fiber. The sheets consist of a mix of fibers and resins, a bit like the molded carbon fiber parts Lamborghini uses. The sheets are manufactured by Japanese company Teijin, which collaborated with GMC to develop the bed. They're all delivered to Continental Structural Plastics (CSP) in Fort Wayne, Ind., for construction into the actual bed. The company, a subsidiary of Teijin, makes a wide variety of composite and plastic parts for the car industry, including body panels for the C7 Chevy Corvette. The rectangular sheets are cut to shape and stacked up at a giant stamping press. Robots pick up sheets and slide them onto a conveyor that goes into a large oven. The heat softens the parts so they can be stamped. The large primary bed parts such as the base are stamped by CSP's enormous 3,600-ton press, and the smaller ones go through a 1,000-ton press. Each press can do different parts using different stamping dies, and CSP switches between dies to produce different batches of parts. After stamping, the parts roll out mostly ready for assembly, but there are rough edges that are trimmed off by water-jet cutters. These cutting machines also create holes for fasteners and for parts such as tie-down hooks and lights. The stamping process also provides the carbon fiber bed with a unique Easter egg. On the bottom of the base of the bed, there are two words: "Connors Way." This is a tribute to Tim Connors, who was the chief engineer of manufacturing at GM and a strong proponent of the carbon fiber bed. He was tragically killed in a motorcycle crash a few years ago. The words were added to honor him, and they were fortunately approved for production. There are some components to the bed that aren't stamped from the flat sheets of material.

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.