1978 Chevrolet Scottsdale 3/4 Ton Camper Special on 2040-cars

Auto blog

Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.

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.

The USPS needs 180,000 new delivery vehicles, automakers gearing up to bid

Winning the New York City Taxi of Tomorrow tender was a huge prize for Nissan, even though the company is still working through the process of claiming its prize. The United States Postal Service has begun the process to take bids for a new delivery vehicle to replace the all-too-familiar Grumman Long Life Vehicle, and that will be a much larger plum for the automaker who wins it, perhaps worth more than six billion dollars. The Grumman LLV is an aluminum body covering a Chevrolet S-10 pickup chassis and General Motors' Iron Duke four-cylinder engine. The USPS bought them from 1987 to 1994, and the 163,000 of them still in service are a monumental drain on postal resources: they get roughly ten miles to the gallon instead of the quoted 16 mpg, drink up more than $530 million in fuel each year, and their constant repair needs like the balky sliding door and leaky windshields have led the service to increase the annual maintenance budget from $100 million to $500 million. A seat belt is about as modern as it gets for safety technology, and the USPS says that assuming things stay the same, it can't afford to run them beyond 2017. Last year it put out two triage requests for proposals seeking 10,000 new chassis and drivetrains for the Grumman and 10,000 new vehicles. The LLV is also too small for the modern mail system in which package delivery is growing and letter delivery is declining. The service says it doesn't have a fixed idea of the ideal "next-generation delivery vehicles," but it listed a number of requirements in its initial request and is open to any proposal. Carriers have some suggestions, though, saying they want better cupholders, sun visors that they can stuff letters behind, a driver's compartment free of slits that can swallow mail, and a backup camera. The request for information sent to automakers pegs the tender at 180,000 vehicles that would cost between $25,000 and $35,000 apiece, and it will hold a conference on February 18 to answer questions about the contract. GM is the only domestic maker to avow an interest, while Ford and Fiat-Chrysler have remained cagey. Yet with a possible $6.3 billion up for grabs and some new vans for sale that would be advertised on every block in the country, we have a feeling everyone will be listening closely come February 18. We also have a feeling the LeMons series is going to be flooded with Grummans come 2017. News Source: Wall Street Journal, Automotive News - sub.