Foot finesse at the starting line

In principle, drag racing is the simplest of motorsports. Here. There. Go. But the execution can be tricky.

For most novices, the hardest thing is the “burnout,” when drivers spin the car’s wheels in the “water box,” a shallow depression in the concrete filled with water. The object is to heat and clean the tires to maximize grip at the starting line. With a rear-drive car and a manual transmission, you must “heel-and-toe” the foot pedals -- that is, press the accelerator and the brake with your right foot while lifting off the clutch with the left, all without stalling the engine. Once the wheels are spinning (and smoking!) the front brakes will hold the car in place until the engine speed (rpm) starts to fall and the engine begins to bog. Then you gently ease off the brake pedal and the car will surge toward the starting line, where it will be “staged,” or put in position for the start.

In a front-drive car a burnout requires less fancy footwork. You pull up the handbrake, holding the locking button with your thumb, then engage first gear and release the clutch. When the engine starts to bog, you ease down the handbrake.

With an automatic transmission, you simply put one foot on the brake and one on the gas. When the car’s powertrain begins to buck and complain, feather the brake and the car will move out of the water box.

The start itself also requires finesse. Two small yellow lights on top of the starting light assembly -- the “Christmas tree” -- correspond to infrared beams across the track. When the front wheels (not the front of the car) are lined up on the starting line, both lights come on.

The three yellow lamps illuminate half a second after the other, followed by the green light. The “reaction time” is measured from the moment the yellow light goes out. A perfect reaction time is .500 second. If a driver’s “R/T” is .575 seconds that means his car left the line .075 seconds after the green light came on. If the car leaves the line in less than .500 seconds, that’s a foul and the red light comes on. Whichever car crosses the finish line first wins, but that’s not always the fastest car. The racer’s “elapsed time” begins when he leaves the line. So a driver who has a quicker reaction time but a slower elapsed time can still win the race.

Finally, there is traction. To maximize performance, a driver must limit wheel spin. When the spinning tires lose grip with the pavement the car slows down -- in other words, maximum acceleration is not simply a matter of flooring the gas and dropping the clutch. You have to modulate the throttle and clutch to get the engine’s power to the ground, much as modern cars’ traction control systems do with electronic intervention.