2014 Chevrolet Silverado 1500 1lt on 2040-cars

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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.

Submit your questions for Autoblog Podcast #313 LIVE!

We record Autoblog Podcast #313 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 #313
2014 Chevrolet Silverado and GMC Sierra introduced

NHTSA closes 4-year GM investigation, issues common sense advisory [w/video]

Since January 2011, the National Highway Traffic Safety Administration has been investigating a possible problem with corroding brake lines in General Motors' GMT800-platform models, like the Chevrolet Silverado and Suburban and GMC Sierra, in states with salt on their roads in the winter. However, as opposed to launching a full recall of millions of vehicles, the government is issuing a common-sense safety advisory to all drivers in snowy states to keep their vehicle's undercarriage clean. It even has a video explaining things. "Older-model vehicles, often driven in harsh conditions, are subject to corrosion over long periods of time, and we need owners to be vigilant about ensuring they, their passengers, and others on the roads are safe," said NHTSA Administrator Mark Rosekind in the announcement of the end of the investigation. The agency was clear in its report that "brake line corrosion seen in the GM vehicles was not unique," and the government "has not identified a defect that would initiate a recall order." Instead NHTSA is advising drivers, especially those of vehicles from before 2007, to wash their vehicle's undercarriage in the winter and spring to remove salt or other de-icing chemicals. It also recommends regular checks by a mechanic to make sure everything is in proper order. According to the investigation documents, for just the GMT800 platform models, NHTSA found 3,645 complaints of brake line corrosion, which included allegations of 107 crashes and 40 injuries. The issue was found to be more common in vehicles over 10 years old. GM has released a statement (embedded below) that the company "supports the consumer advisory from NHTSA urging regular maintenance and care of brake lines on older vehicles." NHTSA Closes Investigation into Brake-Line Failures NHTSA 13-15 Thursday, April 9, 2015 Agency issues safety advisory on preventing undercarriage corrosion WASHINGTON – The Department of Transportation's National Highway Traffic Safety Administration (NHTSA) today issued a Safety Advisory and consumer video encouraging owners of model year 2007 and older trucks, SUVs and passenger cars to inspect brake lines and thoroughly wash the underside of their vehicles to remove corrosive salt after the long winter in order to prevent brake-line failures that increase the risk of a crash.