Rev-mashing: part 2 of 2

Are you rev-matching or rev-mashing? Let’s repeat the question from the end of last week. Where in the corner should you downshift and what are the consequences of shifting at the wrong point.

Red Zone

Lots of people start to downshift during threshold braking. As soon as they hit the brakes, they also depress the clutch and blip the throttle. There are several problems with this.

• The car was already at high RPM and the blip just sent it even higher.
• The car is currently going too fast to engage the lower gear.
  • If you shift to the lower gear immediately, you may destroy the engine by revving it past redline.
  • If you wait with the clutch depressed, the engine and transmission will spin down, negating any benefit of blipping the throttle. When you do engage the clutch, you’ll have to feed it in gradually to prevent locking up the tires. Congrats, you just ruined your brake bias and made the stopping distance longer. You’re also putting wear on the clutch.

Blip-shifting in the red zone is the worst possible place to shift.

Orange Zone

This is generally the best place to downshift. For really long decreasing radius corners, it’s too early though, as you’re still aggressively bleeding speed through half the corner.

Yellow Zone

In this trail-braking zone, your concentration should be on controlling the speed and angle of the car using a combination of brake pedal and steering wheel. It’s not a good time to take your hand off the wheel or dance on pedals.

Green Zone

This is the point of maximum lateral g-force. Your foot is making the transition from brake to throttle. In longer corners with extended trail-braking zones, this is a fine time to shift.

Blue Zone

You’re balancing throttle and steering as you pass the apex and track out to the exit. The over-rotation you initiated in trail-braking has to be wound out some in here. Probably better to keep both hands on the wheel.

Purple Zone

Although it seems way too late, shifting in the Purple zone is an ok place to shift. You’re not going to break any lap records doing it this way, but you’re also not going to do any damage to the car. If you drive through a corner in a gear that’s too high, it’s not that big a deal. If you’re balancing throttle and steering, as you should be, you don’t really need full power anyway. I don’t know anyone who actually downshifts after a corner. It would be like shooting free-throws underhanded: works okay, but looks too silly to be taken seriously.

Demonstrations

Here’s a popular YouTube video instructing how to heel-toe shift. The video overlays footwork and RPMs. Watch as he starts the downshift too early. The revs drop and feeds out the clutch gradually. If you have to release the clutch gradually, you’re not rev-matching, you’re engine-braking (or engine-breaking). One wonders how such a flawed example can have so many views.

Here’s the right way to do it. Notice how quickly the clutch is released as he blips each gear. You might also notice how he changes his hand position depending on which gear he’s selecting. It’s most noticeable for 2nd gear where he rotates his hand thumb-down. He’s not doing this to look cool, but I’m guessing somewhere there’s a ricer in a stanced Honda back-handing every fucking gear…