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When following another vehicle closely, the
airflow off the lead vehicle does not travel across the following one(s) in a
normal manner. Therefore, downforce on the front of the trailing vehicle(s) is
decreased and it does not turn in the corners as well, resulting in an 'aero
push.' This condition is more apparent on the exit of the turns.
A number that is a coefficient of several factors
that indicates how well a race vehicle will travel through the air and how much
resistance it offers. Crewmen work to get the best 'drag horsepower' rating they
can, determining how much horsepower it will take to move a vehicle through the
air at a certain mile-per-hour rate. At faster speedways teams strive to get the
lowest drag number possible for higher straightaway speeds.
A strip that hangs under the front grill, very
close to the ground. It helps provide downforce at the front of the car.
With the advent of radial tires with stiffer
sidewalls, changing air pressure in the tires is used as another setup tool that
is akin to adjusting spring rates in the vehicle's suspension. An increase in
air pressure raises the 'spring rate' in the tire itself and changes the
vehicle's handling characteristics. If his race vehicle was 'tight' coming off a
corner, a driver might request a slight air pressure increase in the right rear
tire to 'loosen it up.'
A car running off the pace near the rear of the
field.
When a car doesn't tend to oversteer or
understeer, but goes around the racetrack as if its on rails, it's said to be in
balance.
The sloping of a racetrack, particularly at a
curve or a corner, from the apron to the outside wall. Degree of banking refers
to the height of a racetrack's slope at the outside edge.
Camber addresses the angle at which a tire makes
contact with the track surface. 'Positive camber' indicates the angle of the
tire is tilted away from the vehicle's centerline while 'negative camber'
indicates the tire is tilted toward the centerline. A typical oval track setup
would have positive camber in the left front and negative camber in the right
front to help the vehicle make left-hand turns.
A rotating shaft within the engine that opens and
closes the intake and exhaust valves in the engine.
The combination of a car's floorboard, interior
and roll cage.
The up-and-down movement caused when a car
travels around corners at high speeds. The side of the car facing the turn
becomes lighter while the extra weight goes toward the outside of the turn.
The part of the tire that's actually touching the
road.
The air used and discarded by the lead car.
The air pressure traveling over the surfaces of a
race vehicle creates 'downforce' or weight on that area. In order to increase
corner speeds teams strive to create downforce that increases tire grip. The
tradeoff for increased corner speeds derived from greater downforce is increased
drag that slows straightaway speeds.
The aerodynamic effect that allows two or more
cars traveling nose-to-tail to run faster than a single car. When one car
follows closely, the one in front cuts through the air, providing less
resistance for the car in back.
The practice of two or more cars, while racing,
to run nose-to-tail, almost touching. The lead car, by displacing the air in
front of it, creates a vacuum between its rear end and the nose of the following
car, actually pulling the second car along with it.
The resistance a car experiences when passing
through air at high speeds. A resisting force exerted on a car parallel to its
air stream and opposite in direction to its motion.
An iron casting from the manufacturer that
envelopes the crankshaft, connecting rods and pistons.
A person who specializes in creating the sheet
metal body of a stock car. Most teams employ two or more.
A solid metal plate that separates the engine
compartment from the driver's compartment of a race car.
The front-most part of the race car, starting
with the firewall.
A holding tank for a race car's supply of
gasoline. Consists of a metal box that contains a flexible, tear-resistant
bladder and foam baffling. A product of aerospace technology, it's designed to
eliminate or minimize fuel spillage.
Slang term for the best route around a racetrack;
the most efficient or quickest way around the track for a particular driver. The
'high groove' takes a car closer to the outside wall for most of a lap, while
the 'Low groove' takes a car closer to the apron than the outside wall. Road
racers use the term 'line.' Drivers search for a fast groove, and that has been
known to change depending on track and weather conditions.
Slang term for the last official practice session
held before an event. Usually takes place the day before the race and after all
qualifying and support races have been staged.
Generally, a race car's performance while racing,
qualifying or practicing. How a car 'Handles' is determined by its tires,
suspension geometry, aerodynamics and other factors.
The time-distance between two cars. Referred to
roughly in car lengths, or precisely in seconds.
Cars that have completed at least one full lap
less than the race leader.
(Also referred to as 'free' or 'oversteer.') A
condition created when the back end of the vehicle wants to overtake the front
end when it is either entering or exiting a turn. In qualifying mode teams walk
a fine line creating a setup that 'frees the vehicle up' as much as possible
without causing the driver to lose control.
(Also referred to as 'loose stuff.') Bits of
rubber that have been shaved off tires and dirt and gravel blown to the outside
of a corner by the wind created by passing vehicles comprise the 'marbles' that
are often blamed by drivers for causing them to lose control.
A term drivers use when referring to how their
car is handling. When a car is neither loose nor pushing (tight).
See Loose
The area where pit crews service the cars.
Generally located along the front straightaway, but because of space
limitations, some racetracks sport pit roads on the front and back straightaways.
The area along pit road that is designated for a
particular team's use during pit stops. Each car stops in the team's stall
before being serviced.
Slang term for the foremost position on the
starting grid, awarded to the fastest qualifier.
(Also referred to as 'tight' or 'understeer.')
'Push' is a condition that occurs when the front tires of a vehicle will not
turn crisply in a corner. When this condition occurs, the driver must get out of
the throttle until the front tires grip the race track again.
The sheet metal on both sides of the car from the
C-post to the rear bumper below the deck lid and above the wheel well.
The section of a race car that begins at the base
of the rear windshield and extends to the rear bumper. Contains the car's fuel
cell and rear suspension components.
An aluminum plate that is placed between the base
of the carburetor and the engine's intake manifold with four holes drilled in
it. The plate is designed to reduce the flow of air and fuel into the engine's
combustion chamber, thereby decreasing horsepower and speed.
These flaps are sections at the rear of a race
vehicle's roof that are designed to activate, or flip up, if the air pressure
flowing across them decreases. In the case of a vehicle turning backwards, the
tendency for an uninterrupted flow of air is to create lift. The roof flaps are
designed to disrupt that airflow in attempt to keep the vehicle on the ground.
Slang term for a way of making chassis
adjustments utilizing the race car's springs. A wrench is inserted in a jack
bolt attached to the springs, and is used to tighten or loosen the amount of
play in the spring. This in turn can loosen or tighten the handling of a race
car.
Slang term for the tuning and adjustments made to
a race car's suspension before and during a race.
Racetracks that are less than one mile in length.
Slang for the period that begins during the
latter part of the current season, wherein some teams announce driver, crew
and/or sponsor changes.
(Also referred to as a 'blade.') The spoiler is a
strip of aluminum that stretches across the width of a race vehicle's rear
decklid. It is designed to create downforce on the rear of the vehicle, thereby
increasing traction. However, the tradeoff, again, is that more downforce equals
more aerodynamic drag, so teams attempt, particularly on qualifying runs, to lay
the spoiler at as low an angle as possible to 'free up' their vehicles for more
straightaway speed.
Stagger is a concept that has largely been
eliminated with the use of radial tires. It refers to the difference in tire
circumference between the left- and right-side tires on the vehicle. Typically,
the left-side tires would be a smaller circumference than the right-side tires
to 'help' the vehicle make left-hand turns.
Slang term used for tire traction.
Slang term for new tires. The name is derived
from the manufacturer's stickers that are affixed to each new tire's contact
surface.
A penalty, usually assessed for speeding on pit
road at the appropriate speed and stopped for one full second in the team's pit
stall before returning to the track.
A racetrack of one mile or more in distance. Road
courses are included. Racers refer to three types of oval tracks. Short tracks
are under one mile, intermediate tracks are at least a mile but under two miles
and super speedways are two miles and longer.
Sometimes called an 'antiroll bar.' Bar used to
resist or counteract the rolling force of the car body through the turns.
A device used to check the body shape and size to
ensure compliance with the rules. The template closely resembles the shape of
the factory version of the car.
Also known as 'understeer.' A car is said to be
tight if the front wheels lose traction before the rear wheels do. A tight race
car doesn't seem able to steer sharply enough through the turns. Instead, the
front end continues through the wall.
Looking at the car from the front, the amount the
tires are turned in or out. If you imagine your feet to be the two front tires
of a race car, standing with your toes together would represent toe-in. Standing
with your heels together would represent toe-out.
(Also referred to as a 'Panhard bar.') This bar
locates the vehicle's rear end housing from left-to-right under it. In
calibrating the vehicle's 'suspension geometry,' raising or lowering the track
bar changes the rear roll center and determines how well it will travel through
the corners. During races, this adjustment is done through the rear window using
an extended ratchet. Typically, lowering the track bar will 'tighten' the
vehicle and raising the track bar will 'loosen' it.
A rear suspension piece holding the rear axle
firmly fore and aft yet allowing it to travel up and down.
A racetrack that has a 'hump' or 'fifth turn' in
addition to the standard four corners. Not to be confused with a triangle-shaped
speedway, which only has three distinct corners.
Air that trails behind a race car and disrupts
the flow of air to the cars behind it.
See Tight
(Also referred to as 'front air dam.') This is
the panel that extends below the vehicle's front bumper. The relation of the
bottom of the valance, or its ground clearance, affects the amount of front
downforce the vehicle creates. Lowering the valance creates more front downforce.
Sometimes called the 'winner's circle.' The spot
on each racetrack's infield where the race winner parks for the celebration.
Refers to the relationship from corner-to-corner
of the weight of the race vehicle. Increasing the weight on any corner of the
vehicle affects the weight of the other three corners in direct proportion.
Weight adjustments are made by turning 'weight jacking screws' mounted on each
corner with a ratchet. A typical adjustment for a 'loose' car would be to
increase the weight of the left rear corner of the vehicle, which decreases the
weight of the left front and right rear corners and increases the weight of the
right front. A typical adjustment for a 'tight' vehicle would be to increase the
weight of the right rear corner, which decreases the weight of the right front
and left rear and increases the weight of the left front.
The practice of shifting a car's weight to favor
certain wheels.
A structure used by race teams to determine the
aerodynamic efficiency of their vehicles, consisting of a platform on which the
vehicle is fixed and a giant fan to create wind currents. Telemetry devices
determine the airflow over the vehicle and its coefficient of drag and downforce.
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