2007 Chevy Tahoe Ltz 4x4 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.

Fingers point to dragged-out NHTSA investigation after second death by ARC airbag inflator

Safety advocates have increased criticism of the federal government's National Highway Traffic Safety Administration after an exploding airbag inflator that's been under investigation for more than six years killed a second person.  On Wednesday, NHTSA posted recall documents filed by General Motors that revealed the second death, the driver of a 2015 Chevrolet Traverse SUV with an inflator made by Tennessee company ARC blew apart, spewing shrapnel. No details were given about where and when the death occurred. NHTSA has said that ARC Automotive of Knoxville has manufactured about 8 million inflators used nationwide in vehicles made by General Motors, Fiat Chrysler (now Stellantis), Kia and Hyundai. “NHTSA should have been all over this along time ago,” said Rosemary Shahan, president of California-based Consumers for Auto Reliability and Safety. “There's just no denying that itÂ’s a (safety) defect.” NHTSA, the agency charged with with keeping America's automobiles and roads safe, began investigating ARC inflators in July of 2015 after two people were injured by flying shrapnel. The investigation became more urgent in 2016, when a Canadian woman driving an older Hyundai Elantra was killed by metal airbag fragments. Public records show only a little progress on the probe. In April, the agency posted a memo in saying it was reviewing volumes of information it received from ARC. Safety advocates such as Shahan say that the dragged-out investigation is an example of the deadly consequences that can result from an understaffed and underfunded agency. The second death should not have happened, Shahan said, and vehicles with faulty ARC inflators should have been recalled faster. The agency, Shahan said, is “grossly underfunded," but it still should have sought recalls of the ARC inflators. She said historically NHTSA has taken little action during Republican administrations but has ramped up safety efforts when Democrats control the White House. Messages were left Wednesday by the Associated Press seeking comment from NHTSA and ARC. At this time, relatively few vehicles are effected. The GM recall covers only 550 Chevy Traverse SUVs from the 2013 through 2017 model years, as well as Buick Enclave SUVs from 2008 through 2017. The automaker said in a statement that the faulty front driver's airbag inflators were either installed at the factory or in replacement airbag modules.

Nissan Leaf sells 1,553 in April, Volt climbs to 905

After three months in the 500 and 600 range, sales of the Chevy Volt climbed to 905 in April. That's up for the year so far – likely due to increasing discounts – but still down 41.5 percent from April 2014. As we've been saying every time the Volt turns in less-than-exciting monthly sales numbers, we suspect a large number of potential Volt buyers are waiting for the next-gen model to arrive in the second half of 2015. While the price for that car has not yet been announced, the updated tech specs show that it will probably be worth the wait for drivers who want the latest and greatest. Over on the Nissan Leaf side of things, April sales were 1,553 units this year. That's the second-best month of the year but down from the 2,088 units sold last April. After the Leaf finally climbed to the top of the cumulative best sellers list for plug-in vehicles last month, the difference between these two leaders is now 1,824 in favor of the Leaf. Nissan says that sales were influenced by the launch of its No Charge To Charge promotion in Indianapolis and Fresno, CA. This deal gives new Leaf buyers and lessees two years of no-cost quick charging in these markets. No Charge To Charge is not available in 15 US markets for (San Francisco, Sacramento, San Diego, Seattle, Portland, Nashville, Phoenix, Dallas-Ft. Worth, Houston, Washington, DC, Los Angeles, Chicago and Atlanta) and will expand to 10 more by the middle of this year. As we do every month, our full wrap-up of US green car sales is coming soon. For now, enjoy discussing these sales figures in the Comments below.