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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.

Fullsize GM SUVs have a problem that's making owners sick

Some fullsize SUV owners are getting sick, thanks to a buffeting and vibration problem in 2015 model year examples of the Chevy Tahoe and Suburban, Cadillac Escalade, and GMC Yukon. According to owners' complaints to the National Highway Traffic Safety Administration, the issue can vary from an annoying vibration inside the cabin to an experience so severe that it leads to dizziness and headaches. General Motors is aware of the complaints, but the fix isn't so simple. According to spokesperson Tom Wilkinson to Autoblog, the company "has been tracking this issue for a while." The problem has a fairly low incidence rate, but when it does occur the issue can be "uncomfortable and annoying for owners." There's no precise cause for the issue, Wilkinson claims, and in some cases, simply balancing the tires or changing the door seals can make it go away. However, not all of the fixes are so simple. AutoGuide dug deep into the problem and discovered a GM preliminary information bulletin that advised dealers to remove the headliner and to check the roof's bonds to the bows that go across the vehicle. However, that document included a note that the solution might not entirely eliminate things. According to AutoGuide, adding Dynamat insulation to the roof sometimes helped the problem. A GM spokesperson also told AutoGuide the company fixed the problem at the end of the 2015 model year, and didn't go into any more detail. This roof issue seems linked to some of the worst droning in these SUVs. According to one complaint from a 2015 Suburban owner to NHTSA: "Roof will not remain attached to the roof bows. This causes the buffeting similar to a window being down when all are up. The results span from annoying to painful." A 2015 Yukon owner claims to have another alleged cause for the problem in a NHTSA complaint from February 2015. This person brought their SUV to the dealer seven times over the course of four weeks for vibrations. The dealer replaced the driveshaft, suspension components, and more, but nothing worked. According to an engineer to the service adviser: "In an effort to prevent roll overs, they designed the frame and body mounts too stiff. There are 40 engineers working on issues, they have no solutions that work across the board." Wilkinson told Autoblog that GM is working with customers on an individual basis to rectify things. Since these are newer vehicles, dealers should also fix the problem under warranty.

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.