CAR and Driver - March 2017

VEHICLE SPEED
Faster entry and
exit speeds charac-
terize the pendu-
lum-turn run.
Notice, however,
that the low-grip
technique is slower
than the conven-
tional one for a
full two seconds in
the middle of the
corner. The point at
which it becomes
slower (001) corre-
sponds to when
the throttle is fully
open and just
before the peak
yaw rate (see^013 ) is
achieved. In other
words, it’s the point
where the car is
rotating fastest.
The driver sacri-
fices speed early to
get the car pointed
in the right direc-
tion sooner and exit
at a higher velocity.

BRAKE-PEDAL
POSITION
Despite entering
the corner 3.5 mph
faster using a
pendulum turn and
left-foot braking,
our driver goes to
the brake almost
15 feet later in the
corner, as he’s
confident the car
will turn rather than
understeer. Notice

the overlap of

braking and throttle

as the pendulum

turn is initiated ( 0 0 2 ,

005). Using the

left-foot technique,

peak braking is

more aggressive

(32 percent of the

pedal travel versus

16 percent) (003)

once the car is

turned back to the

left. Braking also

ends sooner in the

left-foot run (004).

ACCELERATOR-

PEDAL POSITION

Our driver presses

the accelerator at

about 2.1 seconds

in both runs (006).

His enthusiasm for

the throttle comes

early (007) in the

right-foot-only run,

however, and

results in a lack of

commitment. In

that run, after

reaching almost

half-throttle, he

backs off the pedal

until later in the

corner (008), finally

ramping it up to

100 percent (009).

Y’know, the usual

male premature

acceleration.

STEERING-WHEEL

ANGLE

Notice that the

left-foot-braking

run begins with

initial steering input

to the right (010). A

small flick redirects

the momentum

from the initial juke

to the right to

rotate the car

further to the left

as it enters the

corner. Counter-

steering starts at

1.8 seconds (011),

just as the right-

foot-braking run’s

initial turn-in is

beginning (012).

YAW RATE

By measuring how

rapidly a car

rotates around its

vertical axis, yaw

rate illustrates how

much quicker the

left-foot technique

pivots the WRX into

the turn than a

conventional turn

would. See how

peak yaw rate

comes much earlier

in the corner using

left-foot braking

(013). Maybe the

former Van Halen

frontman was onto

something when he

said, “When I drive

that slow, you know

it’s hard to steer.”

Maybe he should

have used his left

foot more often. -60

0

DEGREES/SEC

RIGHT

LEFT

20

YAW RATE

0 0 1

023

VEHICLE SPEED

20

0

0

-300

0

50

SPEED, MPH

PERCENT

PERCENT

DEGREES

35

100

300

BRAKE-PEDAL POSITION

ACCELERATOR-PEDAL POSITION

STEERING-WHEEL ANGLE

(^0) TIME, SEC 6
LEFT-FOOT BRAKING
R I G H T- FO O T B R A K I N G
0 0 2
0 0 8
0 0 4
0 0 6
0 0 7
0 0 9
0 0 3
0 0 5
0 1 1
0 1 3
0 1 0
0 1 2