Everyone is always
asking how to Launch a Subie, so take this for whatever its worth....
The way you launch your Subie is based
mainly on two variables--the type of transmission in your car (manual
or automatic), and the all-wheel-drive.
With a stick shift, the main aim is to
avoid excessive wheelspin by pressing the throttle too much, but also
avoid bogging down the motor by pressing the throttle too little. You
have to get the throttle input just right. Each car engine has a
different rpm range in which it will produce the most power. The trick
is to keep the engine in this sweet spot from the moment you cross the
starting line all the way to the finish line, without any of this peak
power being wasted. Launching a car hard from a dead stop is
accomplished by slipping the clutch and spinning the tires, both within
reason. Power is lost here, but most engines have narrow power and
torque bands, so the fastest launch will include wheelspin and slipping
the clutch. The only way to find out how much slipping would be just
right is to experiment at the track, holding the throttle at various
rpm levels at launch to see how much juice is needed for the quickest
start.
Some people may say a manual benefits
from powershifting during a race, which is to keep the throttle floored
between shifts. It is not a good idea for the beginner, since a
ill-timed shift can cause your engine to over-rev and kill your car.
In general, automatic transmissions are
known as being more useful for lazy drivers than for serious racers.
But it may be surprising for some to know that many pro drag-racing
cars have heavy-duty auto gearboxes. That's because the brake-torque
launch is an automatic specialty. This launch involves keeping the car
stationary by flooring the brakes with the left foot, while using the
right foot to rev up the engine against the torque converter. In
technical terms, this preloads the entire drivetrain with the stress of
a launch, allowing the engine to rev closer to its power and torque
peaks at the starting line. Brake torquing is also beneficial for
turbocharged engines as it allows boost to build up before the launch,
reducing turbo lag. The only problem is that there is a lot of stress
on the transmission, and the consequent heat build-up can destroy your
automatic gearbox. Unless your car has too much power for the tires to
handle, a brake-torque launch usually will not spin the wheels. This is
because the automatic transmission absorbs the shock by design, and
brake torquing actually reduces stress on the rest of the drivetrain.
Instead of a sudden massive load, the drivetrain has the torque applied
slower instead of one huge jolt. If you use a hi-speed stall converter
you are able to apply power quicker, at a pre-determined rpm, making
wheel spin is easier.
Subarus have more traction than they can
use, so higher-throttle launches are possible before a hint of
wheelspin. Generous throttle application is needed since bogging down
the motor is even easier. But these perfect-looking launches are very
hard on the clutch and drivetrain. These cars actually last longer for
drag-race duty when equipped with an automatic, and the easiest of all
to launch, but the most hardcore of these rally-bred cars only come
with a manual in keeping with their corner-carving tradition.
Depending on your skill level,
here is one way of launching a Subaru (*follow
at your own risk, see below for details) :
1. Set DCCD in auto, if a STi.
2. Raise your tire pressure to at least
42 psi. This will assist in better wheel spin and save your shafts from
snapping.
3. At the light, after staging, pulse
the throttle from around 4 to 6 K. It's a quick rev, or "feathering"
the throttle as I call it. This allows the turbo to keep spooling as it
responds to the throttle input. Also, if you can remember, spray your
intercooler now, if you have an STi.
5. Try to time it so you are on an
upsurge at the last yellow light. When the last light hits, go to WOT
and at the same time, release your clutch. Do not sidestep your clutch,
and do not slowly release it. The objective is to be increasing
throttle at the same time you are releasing your clutch. This provides
turbo spool, and in combination with the higher tire pressures, will
assist all 4 tires in breaking loose.
6. Be ready to shift to 2nd gear almost
immediately. Basically, once the revs settle down from the spinning
tire launch, you will be ready for 2nd gear.
7. The rest requires concentrating on
nailing your shift points, and not getting into the rev limiter.
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