SportsCar Feature: Randy Pobst on Shifting Gears

This article first appeared in the November, 2015 edition of SportsCar Magazine. SCCA members can read the current and past editions of SportCar digitally here after logging into their account; To become an SCCA member and get SportsCar mailed to your home address monthly in addition to the digital editions, click here.

Words by Randy Pobst
Image Courtesy of Cadillac

 

Manual shifting is an art form and, unfortunately, one that is quickly becoming obsolete due to the advances of modern technology. I wrote about this a while back, in The Trans, They Are A-Changin’. The work I have been doing with Motor Trend has kept me on the front lines of the latest from the auto manufacturers, including the new Shelby GT350 and R-model Mustangs. They both still use traditional clutch-and-stick gear changes, but hey, they’re Shelbys, retro rods, and so it is quite appropriate.

Another recent example that comes to mind is the Cadillac ATS-V. As seen by their involvement in Pirelli World Challenge (aside: congrats Cadillac and Johnny O’Connell on a fourth title; easier without me there, eh, Johnny? A little), they’re building truly awesome sports sedans. The new ATS-V is available with three pedals, but includes a rev-match and the first flat-shift option I’ve seen on a production car. Both work really well, with the plus/minus factor of mixing human and electronic actuation. You can adjust the assists to suit your mood. How involved do you wish to be today? Or maybe your friend cannot heel-and-toe, so engage the auto-blip and save your synchros while sharing with the inept. On track, the 8-speed automatic works very well, especially for a torque-converter style, except that it usually downshifts after getting on the throttle, whereas the nearer perfect Porsche PDK dual clutch always gets the gear beforehand.

For your human-powered shifting to be optimum, think smooth. Shifts must be nigh imperceptible to the tires. Like buttah, so to speak. Both up and down. Up shifts are easier because the engine revs fall when you lift, but the driver must time it so the clutch release is exactly at the moment the revs match, with zero clutch slip. Always have the clutch up before you get to the power. If it sounds anything like when you pull away from a stop, that’s bad for the clutch. No slip. And, it must be done as quickly as possible, but with no stress on the box.

The synchros will talk to you. Most prefer a slight pause in neutral on the way to the next gear. If notchy, they just take longer to work, or the revs have not fallen enough yet. This is common on newer street cars because throttles no longer close all the way immediately. Slamming it shut causes high vacuum in the intake manifold, sucking oil past the rings and adding emissions – a no-no. Rev your late-model driver and notice how long those revs hang up there. Street cars also have much heavier flywheels than racers, and that keeps the revs up longer, so they demand better rev matching or they will burn your synchros. Synchronizers are just little brakes mounted next to each gear. If you don’t rev-match well, they will rub on the next gear when you pull the lever, slowing it down for you but also heating up. I’ll bet some codger 60 years ago was probably lamenting how those modern synchronized gears were taking all the enjoyment and challenge from driving. The beat goes on.

Downshifts are much more complicated. For you SCCA First Gear types, let’s discuss heel-and-toe. The exact opposite of going up, on the downshift, the engine revs will need to be higher, one way or another.

Your modern high-dollar ride, your right foot, or the clutch and the drive wheels will be bringing the revs up. Stripped to the bone, heel-n-toe means tapping the gas pedal while you move the shift lever. It should sound like BARRR-oooommm. All engines are different, so you’ll have to feel your way. That’s the art and magic. Fully clothed, heel-and-toe means revving the engine while braking and downshifting. Using the ball of your right foot to brake, typically your heel to jam on-and-off the gas pedal, your left foot to clutch, and your hand to move the lever. If you can drive a stick, you’re already doing all of this except the gas-jam.

When you first try heel-and-toe rev matching, always keep braking your first priority. Get a good purchase on the brake pedal, and then stab at the gas with the side or heel while you move the lever. The clutch push, shift, and stab all happen at the same time. It’s a driving art, and I encourage you to learn it. Well-matched gear changes are very rewarding and work best when done quickly.

Double clutching is really fading but will make your transmission last forever. Many real racecars have gearboxes with no synchros at all; think Formula F, and this helps. To your heel-and-toe, add letting the clutch back up when you are in neutral and blipping the throttle. It does an even better job of lining up the gears. Then you put the clutch in again (the double part), and the shift lever will be fairly sucked into the next gear, like a hot spoon in solidified healthy-fat coconut oil. Like this: clutch in, shift to neutral, clutch out, rev engine, clutch in, shift to lower gear, clutch out, gas and go – all while braking smoothly. See why I called it an art?

I’ve learned that on most non-synched racing gearboxes, just matching revs is enough, and double clutch is overkill. With a quick, firm snap of the lever, it goes right in. Non-synchro racing boxes reward a super fast gear change. Don’t baby them like your street tranny. The same with sequentials, like the Porsche 997 Cup; bang it home, fast and true.

Unconvinced? Mount a Garmin VIRB XE action camera (I have a T-shirt and hat from the Tire Rack Solo National Championships they sponsored this year – thanks!) over your shoulder and watch the tach. When you downshift without blipping the gas, the engine drops to idle. Our wheels, meanwhile, are going road speed: 50, 80, 100mph? When you raise the clutch and bring those two together, the force of speeding up that engine tries to lock your tires. Rear-drive cars will try to spin out, like pulling the handbrake (those are going away, too, I’ve noticed). Front-drives will understeer badly as those front tires slide. All wheel drives (Subaru, anyone?) will nicely load up all four, an advantage at covering up our lack of ability.

Teach your children well, Old-School Shifters, ere the art be lost forever, and all our racers end up in static displays.