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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 recalls 55,000 trucks, SUVs for separating axles, fuel pump failures

General Motors issued four separate recalls covering eight of its truck and SUV models for issues related to fuel pump and half-shaft failure. In total, the four campaigns include more than 55,000 vehicles spread out over three brands and six model years, but they've sorted themselves neatly into two categories. Let's dive in.  Axle separation Four models are being recalled for potential axle separation: The 2023 Cadillac XT5, 2023 GMC Acadia, 2023 Chevy Blazer and 2023 Chevy Traverse. The number of units affected is incredibly small (10 units each times two recalls, for a total potential population of just 20 cars). In each case, a small number left the factory with half-shaft assemblies that may have been missing the retention rings that keep them in place, possibly allowing the axles to separate or eject from the transmission. In the case of the XT5 and Acadia, it's the right-side axle assembly; Chevy dealers, however, will have to check the left side.  Fuel pump failure Again, we have multiple vehicles being recalled for similar issues, but in this case they're a bit more distinct. The first of these recalls covers the 2021-2022 Chevy Equinox and 2022 GMC Terrain. GM says a supplier-initiated change may have led to fuel pumps shipping with inadequate clearances to allow for the prescribed flow of fuel, meaning the pump could starve the engine. Customers experiencing the issue may see a check engine light and experience engine hesitation. In some cases, the cars may not start at all. Chevy and GMC will replace the units in question with correctly specified pumps.  The second recall covers a fairly specific cross-section of GM's HD truck lines. 2017-2019 Silverado and Sierra HD trucks sold with the diesel engine and a dual-tank configuration may have shipped with a rear fuel pump that is susceptible to fouling by debris, preventing fuel from properly transferring to the front tank, or, in extreme cases, resulting in a collapse of the rear tank. This issue can lead to inaccurate/erratic fuel tank readings, engine hesitation, a check-engine light or failure to start.  In both cases, GM will inspect and replace faulty units free of charge for customers. Expect notifications to be delivered by March.  Related video: Recalls Cadillac Chevrolet GMC Ownership Safety Truck SUV

2.0-liter turbo four reportedly returning to Chevrolet Equinox line-up for 2022

Chevrolet's popular Equinox crossover will enter the 2021 model year with comprehensive updates and a turbocharged, 1.5-liter four-cylinder as its only available engine. The 2.0-liter turbo four offered through 2020 is allegedly leaving the line-up, but it will be replaced for 2022 with a newer engine that produces slightly less power while returning better fuel economy, according to a recent report. Called LSY internally, the new 2.0-liter turbo four already powers the Cadillac XT4, among other models in the General Motors portfolio. Enthusiast website GM Authority learned it will deliver 237 horsepower at 5,000 rpm and 258 pound-feet of torque from 1,500 to 4,000 rpm. For context, the 2.0-liter available through 2020 (known as LTG) made 252 horses and 260 pound-feet of twist, and the 1.5-liter posts figures of 170 and 203, respectively. As a trade-off for the slight drop in horsepower and torque, the LSY is smoother, quieter and cleaner than the LTG it replaces. Transmission options remain unconfirmed, but the four-cylinder will likely shift through a nine-speed automatic. Front-wheel drive will come standard, and all-wheel drive will be offered at an extra cost. Chevrolet hasn't commented on the report; it hasn't even confirmed the Equinox is losing the LTG engine for 2021. If the rumor is accurate, details about the 2022 Equinox should be released during the first half of 2021. GM Authority added the GMC Terrain, which is closely related to the Equinox, will receive the new engine for 2022 as well. Both should have gotten it for 2021, but the on-going global pandemic delayed its launch. Related Video: