heel_and

Last month we opened with a discussion about the language that is used by Porsche techies. It is a little known language referred to as porshese. It usually can be heard at driving events and tech sessions. However, it has recently infiltrated the ranks of everything from concours to tours and rallies.

The term we will discuss this month is "Heel and Toe" . This is a term which describes a technique of applying pressure to the brake pedal and the gas pedal at the same time. The reason for using this technique would be to increase engine RPM for a downshift while braking before a corner. Since this is done while downshifting, and since humans have only two feet, this means that two pedals must be actuated by one foot. If the name was an accurate representation of how this technique was performed it would be called "big toe - right side of foot", which is nowhere near as cool as "heel and toe".

The way it is performed varies slightly from car to car, but the theory is all the same. The first step is to apply pressure to the brake pedal with the ball of your right foot just below the big toe. While maintaining even brake pressure, roll your foot to the right, pivoting on your heel. Let your twisting foot apply pressure to the gas pedal while depressing the clutch and downshifting.(brake, clutch, throttle, shift, then throttle again) Sound easy? Let me just say that three different pedal inputs using only two feet can be a significant challenge if you want to do it smoothly. (See figure 1)

Older Porsche models (non-power brake) are the easiest on which to perform heel and toe. This is due to the fact that the brake pedal is usually more even with the gas pedal under hard braking. On later model cars, the brake pedal is higher than the accelerator under braking , making a pedal adjustment necessary to more easily perform this valuable task.

1977-97 911's - Below the pedal board is a two foot long metal rod which connects the brake pedal to the master cylinder. There are 15mm locknuts on each end of this rod to facilitate shortening of the rod for proper heel and toe adjustment.

924-944-968-928 - These cars have a push rod between the brake pedal and the brake booster. A simple shortening of this rod will get the desired pedal height. After the desired pedal height change is achieved the brake light switch needs to be repositioned or the brake lights will stay on all of the time.

If the height is good, but the gap between the brake and gas pedals is still to great, the right side of the gas pedal can be shimmed up to bring it closer to the brake pedal. These two adjustments will get 90% of all Porsches' properly set up for heel and toe.

After the pedals are set up, the next step is to tune the drivers ability. This technique takes lots of practice and is only an advantage when it is done smoothly and without having to think. Fortunately, this is one racing technique that can be safely practiced in every day driving.

Step #1

The downshift begins with a full throttle acceleration towards a corner.

Step #2

Lift the right foot from the gas pedal and press the brake pedal.

Step #3 / 4

Just before the braking is done, the left foot depresses the clutch pedal. The right hand begins the downshift

.
The right foot is still applying, but easing up on the brake pressure as the car approaches the turn-in, then the foot rotates so the heel is above the corner of the gas pedal.

As the shift passes through neutral, the right heel gives a quick push of the gas pedal to rev the engine quickly (the ball of the foot is still on the brake easing up even more)

Step #6

The right foot completes the braking with a smooth release

Step #5

The left foot releases the clutch, the right foot rotates off the gas. Done correctly the RPMs generated by the throttle blip above matches the RPMs needed, and as the clutch is released the engine engages smoothly with the current wheel speed. There should be no forward or braking lurch when the clutch is let go

Step #7

The right foot moves over to the gas pedal to assume the normal position at first only to maintain the pressure needed to sustain the vehicle speed thought the first part of the corner. Then pressure is gradually applied to accelerate out of the turn.