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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.

Personal testimonies show real-world effect of plugging in with Chevy Volt

At this point, there are tens of thousands of individual stories about what it's like to live with a Chevrolet Volt. But it also remains informative to take a look at one of these in depth. For example, one Atlanta-area Volt owner says he's cut his cents-per-mile ownership costs by almost 40 percent compared to his previous car primarily because of his ability to drive almost all the time on electric power. Jeffrey Cohen told Clean Technica that he put about 14,000 miles on his Volt extended-range plug-in hybrid for the year that ended October 2013, and that more than 92 percent of those were on electrons. He estimates his "lifetime" miles per gallon rating at a whopping 384 mpg, a figure pushed upward by the fact that he installed a Level 2 charger at home while his employer added an external 110-volt charger at work. Cohen is spending 45 cents a mile for his car, compared to 73 cents in his Infiniti M35. As a result, he's spending 45 cents a mile for his car, compared to 73 cents a mile with his prior vehicle, an Infiniti M35. About two-thirds of those Volt costs are for the $349-a-month lease payments, while 15 percent is insurance, 11 percent is for the charger and seven percent for the gas and electricity that actually powers the car. Helping lower that last figure is an overnight electricity rate that's about 10 percent of Cohen's daytime rate. Chevy parent General Motors hopes such testimonies will re-trigger sales for the Volt in 2014. Last year, GM sold 23,094 Volts, down 1.6 percent from 2012. We expect our readers have similar stories they'd like to share in the Comments. Related Gallery 2011 Chevrolet Volt: Review View 22 Photos News Source: Clean TechnicaImage Credit: Lead image: AP Photo/Jae C. Hong Green Chevrolet GM Electric running costs

GM resumes production of its 3.0-liter turbodiesel straight-six

General Motors temporarily stopped taking orders for trucks and SUVs equipped with the 3.0-liter Duramax turbodiesel six-cylinder engine in August 2021 due to a supplier shortage. Reports claimed the pause would last through 2021, but the engine is already back in production. Enthusiast website GM Authority learned from sources inside General Motors that the straight-six is once again coming off the assembly line at the Flint Engine Plant in Flint, Michigan. There's no official word on precisely what the problem was linked to and whether it was related to the on-going chip shortage that's wreaking havoc across the automotive industry. All we know is that the pause lasted for about two weeks. Called LM2 internally, the six is available in Chevrolet's Tahoe, Suburban, and Silverado 1500 and in GMC's version of these trucks. It's also an option in the Cadillac Escalade. It develops 277 horsepower at 3,750 rpm and a V8-like 460 pound-feet of torque at 1,500 rpm in every application, and it allows these big behemoths to post surprising fuel economy numbers. Fitted to a rear-wheel-drive Tahoe, the Duramax returns 21 mpg in the city, 28 mpg on the highway, and 24 mpg in a combined cycle, figures that make it more efficient than a Blazer. Demand for the diesel-powered trucks is relatively high. While the shortage undoubtedly took a toll on sales, the Duramax represented 8% of Suburban sales and 6% of Tahoe sales in May 2021. There are no other diesel-burning full-size SUVs available new so they have the market to themselves. On the truck side, Ram still makes the EcoDiesel available on some 1500 trims but Ford abandoned the segment. Related Video: Featured Gallery 2021 Chevrolet Tahoe RST View 24 Photos Chevrolet GMC Truck SUV Diesel Vehicles