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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.

GM natural gas-powered vans recalled due to possible leak

General Motors is recalling almost 3,200 of its compressed-natural-gas powered utility vans because of possible leaks. GM and the National Highway Traffic Safety Administration (NHTSA) released a notice last week saying that 3,196 Chevrolet Express and GMC Savana CNG vans are on recall, though no accidents have been reported due to the possible issue. The recall is specifically for vans for model years ranging from 2011 to 2014. The recall stems from a potential leak from the compressed natural gas high-pressure regulator, and such a leak could cause a fire or explosion. GM will replace the vehicles' high-pressure regulator in order to fix the problem, will do it free of charge and is instructing owners to contact Chevrolet or GMC customer service to arrange for the parts replacement. Utility vehicle makers like General Motors have pushed for fleet sales of CNG-powered vans and trucks for the past few years and have touted them for their cheaper refueling costs relative to standard gasoline, not to mention the fact that natural gas can be readily sourced from throughout North America (thanks, fracking). According to CNGPrices.com, compressed natural gas sells for about $2.22 a gallon, on average, while the AAA is pegging the average price of gas at $3.34 a gallon. NHTSA has posted information on the recall here. Featured Gallery News Source: NHTSA via Reuters Green Chevrolet GM GMC Natural Gas Vehicles CNG gmc savana

GM may have teased a whole group of electric vehicles

During GM's big CES press conference, the automaker highlighted a number of its upcoming electric car-related projects from delivery vans to the upcoming flagship Cadillac Celestiq. In the middle of it all, a collection of mystery cars sat in the background behind speakers. They were in the dark, lit only with their running lights, and while it's possible they're just generic filler cars or concepts, we think they could be future products. Our best shot of the cars together is shown above, and we can pretty easily identify three of the vehicles. In the center is obviously the GMC Hummer EV. On either side of it are Cadillacs. To the left seems to be the Lyriq crossover, and to the right is the Celestiq sedan. Two of these cars have production dates, and the third has been confirmed for eventual production, just without timing. This is why we think the rest of the cars are upcoming models. The next most easily identified car is on the near right behind the Cadillac Celestiq. It very clearly has a Chevy bowtie illuminated in the running lights. And looking closely, it appears to be a pickup truck. It's difficult to make out anything more than that. The nose does look a bit more rounded and swept back than the brick-like designs of the Silverado truck line. That also squares with what seemed to be the upcoming truck that appeared in the background of yet another GM presentation. GM previously said this electric Chevy truck will be a full-size model with up to 400 miles of range. That leaves us with three more mysterious models. Over to the left behind the Cadillac Lyriq are what appear to be a pair of crossovers. The one on the far left looks low, curvy, and possibly with a fastback roof. The one on the right is taller, boxier, and probably more of a full-size people hauler. It's hard to say much more beyond that. They could be new electric Buicks, which would fit in nicely with that brand's crossover portfolio, and would likely be highly successful in China, where Buicks, crossovers and electric cars are all rather hot commodities. As for the mystery car on the far right, it's quite a puzzle. We can at least rule out Buick and Cadillac, and GMC since it's definitely a car, and a rather small one compared with the other cars on display. That leaves Chevy, and possibly the autonomous division Cruise. We're leaning toward it being a Chevy, since the first Cruise vehicle is going to be a boxy pod of sorts.