2005 Chevrolet Silverado 3500 Duramax Dually Lt on 2040-cars

Auto blog

Submit your questions for Autoblog Podcast #321 LIVE!

We're set to record Autoblog Podcast #321 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.
Discussion Topics for Autoblog Podcast Episode #321
Unibody Ford Ranger replacement

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.

Looking back at the Citation IV concept that likely shaped the GM EV1

Those who forget history are condemned to repeat it. We're not sure how that applies to the GM EV1, but we'd still like to share something from Autoline Daily, an online automotive new show with our friend John McElroy. He's been covering the business for decades now and recently found something interesting: pictures of the 1984 Chevrolet Citation IV concept, seen above. Displayed half a decade before the first electric concept that would become the EV1 (inset), McElroy says it's now clear that the elegant, aerodynamic EV1 took a lot of styling cues from the Citation IV, which was developed in part thanks to GM's new-at-the-time Aerodynamics Laboratory. We agree with him that the spats over the rear wheels, the flush glass, and the covered headlights all bear a certain kind of similarity between the two cars. That the colors almost match is a nice coincidence. The Impact (the concept version of the EV1) looked "frumpier," McElroy says, because it wasn't as long as the Citation. You can read a lot more about the Citation IV here and check out McElroy's thoughts in the video below. Find the Citation starting at around 3:45. This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.