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Leak reveals GM's 2017 heavy duty diesel trucks to get 910 lb-ft of torque [UPDATE]

UPDATE: Chevrolet officially announced specs for the 2017 Silverado HD and the rumors were true. The truck's new Duramax 6.6-liter turbo-diesel V8 puts out 445 horsepower and 910 pound-feet of torque. Chevrolet says the new motor produces 19 percent more torque and 12 percent more horsepower, while producing 35 percent fewer emissions. Overall, the new engine is a big improvement over the current motor, which generates 397 horsepower and 765 pound-feet of torque. According to Truck Trend, GM's newest heavy duty pickup trucks will pick up quite a bit more power and torque. The publication spotted a recent GM Powertrain ordering catalog that had the engine specs for the 2017 model year and managed to get some screenshots before the catalog was taken down, and they can be viewed here. The screenshots revealed that the 6.6-liter turbodiesel V8 powering the Silverado and Sierra heavy duty models will boast 445 horsepower and 910 lb-ft of torque. This is a substantial gain over the current models' 397 horsepower and 765 lb-ft of torque, and as Truck Trend points out, it exceeds the Ford Super Duty line's horsepower output of 440, but comes short of the 925 lb-ft rating. Truck Trend credits part of this output gain to the new intake system GM will introduce on the 2017 heavy duties. The intake gets 60 percent of its air from a scoop on the hood, with the other 40 percent coming from behind one of the front fenders. GM doesn't reveal horsepower figures in the press release about the scoop, but it does say the cooler air helps with maintaining the engine's output, and that the scoop does produce a ram-air affect, providing more air at speed. As we know, more air plus more fuel equals more power, but there's likely more to the power increase in this engine than only the intake. Related Video: News Source: Truck Trend via MSN Chevrolet GM GMC Truck Diesel Vehicles

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.

Autoblog Podcast #380

Episode #380 of the Autoblog podcast is here, and this week, Dan Roth, Chris Paukert and Seyth Miersma talk about the Fiat-Chrysler five-year plan, the seeming demise of the Nissan Cube, and proposed legislation to require speed limiters with a 68-mph maximum on America's tractor trailers. We start with what's in the garage and finish up with some of your questions, and for those of you who hung with us live on our UStream channel, thanks for taking the time. Check out the new rundown below with times for topics, and you can follow along down below with our Q&A. Thanks for listening! Autoblog Podcast #380: Topics: Fiat-Chrysler five-year plan Nissan Cube on the way out? Big rig speed limiters coming? In the Autoblog Garage: 2015 Mercedes-Benz S63 AMG 2014 Chevrolet Sonic RS Sedan 2014 Honda Odyssey Touring Elite Hosts: Dan Roth, Chris Paukert, Seyth Miersma Runtime: 01:44:17 Rundown: Intro and Garage - 00:00 Fiat Chrysler Plan - 29:40 Nissan Cube - 01:07:33 Semi Speed Limiters - 01:17:33 Q&A - 01:27:35 Get the podcast: [UStream] Listen live on Mondays at 10 PM Eastern at UStream [iTunes] Subscribe to the Autoblog Podcast in iTunes [RSS] Add the Autoblog Podcast feed to your RSS aggregator [MP3] Download the MP3 directly Feedback: Email: Podcast at Autoblog dot com Review the show in iTunes Auto News Earnings/Financials Plants/Manufacturing Podcasts Rumormill Chevrolet Chrysler Dodge Fiat Jeep Nissan nissan cube speed limiters