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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.

Watch this week's Top Gear America used-car challenge

Top Gear America is back for the penultimate episode of the first season. Used car challenges were some of the highlights of the original UK edition. In our exclusive clip, Tom Ford, Antron Brown and William Fichtner run their $7,000 sports cars in a drag race. As expected, the trio chose very different cars for the challenge. Watch the video to see if a Subaru WRX's all-wheel drive can overcome a power deficit to beat a Ford Mustang and a Chevy Corvette. Brown and Fichtner also spend some time relaxing with an old Jeep Wagoneer. Like them, we're really hoping Jeep will bring back the Wagoneer nameplate. Brown also drives a Maserati Levante, proving that not all family cars need be boring. This week's guest star is actor, rapper and former host of Pimp My Ride, Xzibit. Top Gear America airs Sundays at 8 p.m. Eastern on BBC America. Related Video: Celebrities TV/Movies Chevrolet Ford Subaru Top Gear exclusive top gear america

Why the Corvette's Performance Data Recorder can be illegal in some states

The Performance Data Recorder with Valet Mode available on the 2015 Chevrolet Corvette Stingray seems like a fantastic tool for many owners. Whether they are taking 720p video while lapping the track in their new 'Vette, or just want to protect their purchase from inconsiderate joyriders, the system offers a lot of functionality in one package. However, one of the PDR's features might get buyers in trouble with the law, and it has nothing to do with recording some illicit high-speed driving on a favorite back road. The problem hinges on the various state laws concerning a person's right to privacy.
According to a letter posted by Jalopnik, Chevy dealers are asking 2015 Corvette owners not to use the Valet Mode portion of the PDR because it records audio in the cabin, in addition to performance specs. That's a problem because privacy laws vary from state to state with some requiring just one side's consent to tape sound and others requiring all parties to agree. According Jalopnik, 15 states mandate everyone's permission beforehand, but it's not clear whether these numbers are up to date. (Actually, the report varies, saying 13 states in some places and 15 in a list.)
According to the letter, Chevy is already working on a software update for the near future to rectify the issue. It's possible that simply adding a warning to drivers and the ability to turn off the audio recording function in Valet Mode might solve the problem. Obviously, this doesn't preclude Corvette drivers from using the performance aspect of the PDR, and owners are free tape lap after lap at the track.