Drag Racing - The Perfect Launch
Drag racing, a contest between two cars beginning from a
complete stop over a distance of a 1/4 mile (1320 feet) depends
heavily on first 60 feet of the race, or the launch. The
technique used for launching varies greatly depending on the how
the car is equipped. The type of transmission, which wheels are
being driven, tires, power, suspension and track preparation all
play key roles in how to go about getting the best launch
possible from the car.
Improvements on the time it takes for the car to travel the
first 60 feet down the track have significant implications on
the final ET (estimated time). As a general rule, improvements
in the 60 foot time, are magnified by 2x on your final ET. For
example, a Dodge Viper GTS that runs a 12.2 @ 120 MPH in the 1/4
mile with a 60 foot time of 2.0 can make significant
improvements to it's 1/4 mile times by obtaining a better
launch. If the Dodge Viper GTS is able cut .2 (two tenths) of a
second off it it's 60 foot time, by covering the first 60 feet
in 1.8 seconds, it's final ET for the 1/4 mile would be around
11.8 @ 119 - 121MPH. More examples can be found by searching
through the thousands of 60 foot records in the
http://www.dragtimes.com drag racing database.
The best possible launch is obtained by obtaining the optimal
balance of applying the most amount of power to the ground with
the least amount of wheel spin. If too much power is applied
during the launch and the tires spin, the resulting 60 foot time
will be poor. The same goes for not applying enough power,
thereby causing the car's engine to bog, and having the car limp
off the line slowly.
When launching a car with an automatic transmission, a technique
called power braking is used. After properly staging the car at
the drag strip's staging lane, tightly hold down the brake with
one foot, while slowly applying the accelerator peddle with the
other foot. The car's engine RPM (revolutions per minute) should
slowly increase to a point where the car will either start to
move or start spinning the tires. Hold down both the brake and
accelerator peddles just below the point where the car is
starting to move or spinning the tires. When the christmas tree
lights reach the last amber light before the green, lift off of
the brake and slowly push the gas peddle all the way down. The
correct RPM to launch at will be different every car depending
on all of the variables mentioned earlier. Start conservative
with the first launch and keep increasing the RPM at which the
car is launched at during the subsequent runs. If the car starts
spinning the tires after the launch, lower the launch RPM and
try again.
When launching a car with a manual transmission come to a
complete stop after the car is properly staged. Press the clutch
in all the way with one foot while pressing the accelerator
peddle down with the other foot, raising the engine RPM to a
constant moderate level for the first launch. Lift up on the
clutch peddle to the point where the car is just about to start
moving and hold both peddles still. When the christmas tree
lights reach the last amber before the green, slowly release the
clutch while quickly applying the accelerator peddle enough to
launch the car quickly, but not too much to induce a large
amount of wheel spin. Start conservative with the first launch
and keep increasing the RPM at which the car is launched at
during the subsequent runs. If the car starts spinning the tires
too much after the launch, lower the launch RPM and try again.
To obtain better launches and bring down 60 foot times even
more, the use of drag radial or full slick tires can be used on
more powerful cars that have trouble launching at any RPM on
regular street tires. Drag radials and full slicks usually
require a burnout to heat up the tires and clean them from
debris for optimum performance. A burnout is a rapid spinning of
the car's tires while the car stays relatively still.
All wheel drive cars (AWD) are typically the easiest to launch
because the engine's power is distributed to 4 wheels instead of
two. Rear wheel drive (RWD) cars typically launch better than
front wheel drive (FWD) due to the transfer of weight to the
rear tires during the launch, causing an increase in traction.
If the car has aftermarket adjustable suspension, adjustments
can be made specific for drag racing to increase the weight
transfer to the driving wheels.
The track's launch pad preparation also plays an important role
in how well and how hard cars can launch. The launch area is
usually prepped with traction compounds to add to the stickiness
of the track. A well prepped track will definitely help drop 60
foot times and result in lower 1/4 mile times.
During the breaks and cool down periods between drag racing
runs, make detailed notes about how you launched on the back of
each timeslip. These notes can help you diagnose launching
issues, fine-tune subsequent launches and show improvements in
the search for The Perfect Launch.