1995 Chevrolet K1500 Sport Z71 Silverado on 2040-cars

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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.

Nissan Leaf makes it 19 in a row for record sales; Chevy Volt drops 21 percent

The Nissan Leaf continues its streak of "best month ever" sales with 2,881 EVs sold in September. Compared to the 1,953 sold in September 2013, that represents an increase of 47.5 percent and, as Nissan itself must be tired of saying by now, it marks yet another best month ever, same as last month and now the 19th in a row. Okay, sure, we know, Nissan will tout this run for as long as it can, but we're certainly expecting it each month, so if it ever doesn't happen, it'll be interesting to see how Nissan talks about it. Year-to-date, Leaf sales are up 35.7 percent compared to 2013. In any case, Nissan's director of EV marketing, Toby Perry, sent AutoblogGreen a statement that said, "Nissan Leaf owners have turned into some of our best marketers, and they jump at any opportunity to share their enthusiasm with friends and family. Take National Drive Electric Week – a grassroots celebration of all things EV and the perfect platform for LEAF owners to showcase the benefits of going electric. After celebrating with EV owners in more than 130 cities across the country, we saw a significant increase in Leaf showroom visits with midweek traffic just as heavy as what we see on the weekends." Year-to-date, Leaf sales are up 35.7 percent compared to 2013. Over on the Chevy Volt front, things aren't quite as rosy. After coming off a good August (the best sales month of 2014 by almost 500 units), Volt sales were down to 1,394, a decrease of 21.1 percent compared to September 2013. So far this year, Volt sales are down 13.2 percent year-over-year. It's kind of a stretch, but perhaps people are already waiting for the next-gen Volt, which will be revealed at the Detroit Auto Show in January, to go on sale? Speaking of things we say every month, our in-depth round-up of US green car sales is in process and will be appearing soon. Until then, please discuss how these two long-standing plug-in champs are doing on the sales floor. Green Chevrolet Nissan Electric Hybrid PHEV ev sales hybrid sales

MotorWeek looks back at 1995 Chevy Tahoe, GMC Yukon

MotorWeek's Retro Review series gives us a nostalgic look back at some of the best sports cars and luxury sedans available in the 1980s and '90s. For its latest clip, the show shifts gears to remember the 1995 Chevrolet Tahoe and GMC Yukon. Similar to the success of crossovers today, SUVs were tallying big sales and making big money for automakers in the mid-'90s. The Tahoe and Yukon filled slots in the market as steps down from the larger Suburban. These twins weren't wanting for space, though, with plenty of room to haul around a family. MotorWeek came away generally impressed too, and called the models some "of the better riding sport utilities we've ever experienced." This review comes with some jazzy, electric guitar licks to enjoy in the background.