The NASCAR Vehicle

The original concept of a NASCAR race car wasSpeedway in Talledega, Alabama. Fans were
that is was supposed to be composed of stockinjured in the stands and NASCAR took action to
parts-parts you would buy in an auto parts store.restrict the speed of the vehicle through what is
In some respects that is true but not totally. Theknown as a restrictor plate. This also gave birth
race car is a high performance racing machineto the term "restrictor-plate racing."
designed to withstand high G-forces when bankingThe physics of the restrictor plate have to do
on turns. Let's look at what makes up this vehicle.with reducing air intake into the intake manifold of
The first component most are interested in is thethe engine. Less air will result in lower combustion
engine of a NASCAR racing vehicle. This enginethus reducing horsepower. The restrictor plate is a
actually is very close to that which you have insheet of metal with four holes bored in it at
your car (provided you have a big engine) but it isprecise tolerances. The plate is then mounted
customized so that it can withstand highbetween the intake manifold and the carburetor.
temperature and torque. All parts in the engine ofAfter that, the NASCAR vehicle should not be
a are machined to within very tight specificationsable to exceed speeds of 200 mph.
so that there is a minimum of friction. TheIt would seem like the restrictor plate would
carburetor is designed to let in the volume of airresolve the safety problem but many professional
and fuel mixture required to sustain high speedsdrivers have been asserting that it creates more
for lengthy spans of time. There are no fuelpotentially unsafe situations in a race. If you think
injectors in the race cars engine.about the difference between a motor scooter
The first modification to the NASCAR vehicle wasand a motorcycle you can see where a restrictor
to smooth out the ride. Early races were run onplate could create problems. Many times a motor
tracks that were very bumpy and this causes ascooter has an accident where a motorcycle
lot of damage. Today, the NASCAR vehicle iscould have avoided it because of its increased
basically a body molded from sheet metal on aability to accelerate (a motorcycle can accelerate
frame supported on the inside by bars made ofquicker to avoid an oncoming threat). It is the
sheet tubing. The vehicle is not a stock vehiclesame complaint among almost all of the racers
any longer as each component is hand-craftedwith restrictor plates. They have identified
and assembled. The car is built with safety in mindsituations where the cars bunch up and the driver
while giving it the ability to maintain speedsonly has one choice and that is to slow down.
approaching 200 mph. Driver comfort is not theSpeeding up to avoid the congestion is not an
focus.option because the other cars may be at the
The NASCAR vehicle at one time was able torestrictor plate limit too.
reach speeds in excess of 200 mph and that allBut as for now, the restrictor plate is a
changed in 1987 when Bobby Allison's race carrequirement in the race car vehicle on the
flew into a section of fence at the Talladegamajority of tracks.