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(compiled by The Partytime Racing Team members from various sites on the internet. Mainly NHRA and IHRA)

Air box:
Used primarily on Pro Stock Bikes, it settles "negative air" around carburetors the way a hood scoop does on a car.

Air foil:
The same as a wing, a stabilizer, generally used to create down-force, which increases stability and tire-to-track adherence at high speeds.

Bang the blower:
An explosion inside the supercharger caused by a flame from the combustion process accidentally re-entering the supercharger, where fuel and air are present. Generally caused by a stuck or broken intake valve that normally would be closed during the combustion sequence.

Used only in handicap racing, the term breakout refers to a contestant running quicker than he or she predicted his or her vehicle (called a dial-in). Unless his or her opponent commits a more serious infringement (e.g., red-lights, crosses the center line, or fails a post-race inspection), the driver who breaks out loses. If both drivers break out, called a double-breakout, the one who runs closest to his or her dial-in is the winner.

Burned Piston:
When a cylinder runs lean (too much air in the air-to-fuel mixture) and excessive heat burns or melts the piston.

Spinning the rear tires in the water to heat and clean them prior to a run for better traction. A burnout precedes every run.

Cherry picker:
A cherry picker is that competitor that sits in the back of the lanes and purposefully tries to 'pair-up' with whomever he thinks will be the easiest to defeat.

Christmas Tree:
The Tree, as it is often called, is the noticeable electronic starting device between lanes on the starting line. It displays a calibrated-light countdown for each driver.

Clutch Can:
The bell-shaped housing, or bell-housing, used to encase the clutch and flywheel.

Clutch Dust:
Carbon dust created when the surface of the clutch discs wear as they slide together during the clutch-lockup process.

Clutch lockup:
The progression of the clutch-disc engagement controlled by an air-timer management system.

Delay Box:
The 'box', as it is usually called, is an electronic device to aid the driver. The driver can dial a number into the box called the delay. Usually used in conjunction with a transmission brake and two-step, the driver can hold down a button mounted on his steering wheel, activating the trans-brake and the two step, and then let go of the button the instant he sees the 'first flash' of amber from the first bulb. The delay box will then count the thousandths of a second dictated by the driver, and then release the trans-brake and the two step. The driver can adjust his reaction times by changing the number on the delay box. The theory is that a driver instinctively reacting to an initial signal (the first amber) will be quicker and more consistent than a driver that must train himself to wait for the third amber/. This is indeed often the case, making the box a controversial (but legal) tool in many classes.

Deep Staged:
A driver is deep staged when, after staging, he or she rolls a few inches farther, which causes the pre-stage light to go out. In that position, the driver is closer to the finish line but dangerously close to a foul start.

A dial-in is your educated guess or predictions of your car's E.T. Dial-ins are used to handicap cars in elimination. When two cars race, the two dial-ins are subtracted, and the slower car is given the difference in a head start. The head start is shown by the Christmas Tree coming down in his lane first. The theory is that if both drivers have identical reaction times, and both hit their dials exactly, they will meet on the finish line at exactly the same time. Example: You made time trials with these E.T.'s 15.05, 15.07. 15.01. If you decide to dial-in at 15.00, and your opponent dials a 12.00, you will receive a 3.00 second head start.

Dialing under allows drivers in handicap categories to select an elapsed time quicker than the national index. As with a dial-in, the driver selects a dial-under, or E.T. that he or she thinks the car will run, based on qualifying performance. The breakout rule is in effect.

A blanket made from ballistic and absorbent material, often Kevlar TM, which surrounds the oil pan and serves as a containment device during engine explosions. Required on Top Fuel dragsters, Funnycars, Alcohol Dragsters and Alcohol Funnycars.

In an engine, displacement is the total volume of air-to-fuel mixture that an engine theoretically is capable of drawing into all cylinders during one operating cycle.

Dropped Cylinder:
When a cylinder becomes too rich (too much fuel in the air-to-fuel mixture) and prevents the spark plug(s) from firing.

Purposefully lifting off the accelerator or hitting the brakes with the intention of letting your opponent hit the finish line first, hopefully to force him to breakout while you do not.

Elapsed Time:
An elapsed time or E.T., is the time it takes a vehicle to travel from the starting line to the finish line. A car starts or triggers the E.T. timer by reconnecting the staging beam (ie, when it leaves the starting line). Starting the E.T. timer is identical to stopping the Reaction Time (R/T) timer.

After qualifying, vehicles race two at a time, resulting in one winner and one loser. Winners continue to race in tournament-style competition until one remains.

Foul Start:
A foul start is indicated by a red light on the Christmas Tree when a car has left the starting line before receiving the green light, or starting signal.

Fuel Injection:
A fuel-delivery system which replaces conventional carburetion. Fuel injection delivers fuel under pressure directly into the combustion chamber or indirectly through the airflow chamber.

Full Tree:
Used in Competition, Super Stock, and Stock, for which a handicap starting system is used to equalize competition. The three amber bulbs on the Christmas Tree flash consecutively five-tenths of a second apart, followed five-tenths later by the green starting light. A perfect reaction time on a full tree is .500

Guard Beam:
A light beam-to photocell connection located 16 inches past the staged beam that is used to prevent a competitor from gaining an unfair starting-line advantage by blocking the stage beam with a low-installed object such as an oil pan or header collector pipe. If the guard beam is activated while the staged beam is stilled blocked, the red light is triggered on the Christmas Tree and the offender is automatically disqualified.

Fine-tuned exhaust system that routes exhaust from the engine. Replaces conventional exhaust manifolds.

This is when two competitors run (head-to-head) against each other within a particular time bracket. Most racing in the higher classes are run in this way. Breakout rules apply.

A hemi engine has a hemispherically shaped cylinder-head combustion chamber, like a ball cut in half.

Reacting quicker to the Christmas Tree starting lights to win a race against a quicker opponent.

When a cylinder fills with too much fuel, thus prohibiting compression by the cylinder and causing a mechanical malfunction, usually an explosive one.

The expected performance for vehicles in a given class as assigned by NHRA. It allows various classes of cars in the same category to race against each other competitively.

Interval Timers:
Part of a secondary timing system that records elapsed times, primarily for the racers' benefit, at 60,330,660. and 1000 feet.

Killing the Tree:
This phrase is said to describe a driver that has been getting consistently great reaction times. Also, "I nailed the tree on him" means that you had a much better light than your opponent.

Lights has two different meanings, which are contextual. It can either refer to the starting lights on the Christmas Tree, or the top-end 'lights' or 'eyes' , which is talking about the photocells near the finish line (i.e., the last 60 feet). "The lights came down" refers to the tree, whereas, "I was ahead of him going through the lights" refers to the top end.

A line-lock allows the driver to set the brakes on just one set of tires. Usually, racers put a line lock on the front tires in order to aid their burnouts. They set the brakes, hold a button, and then release the brake pedal. The brakes will release on the back, but hold the front brakes until the button is released. Some people try to simulate a Transbrake by having four-wheel line-locks. This allows the driver to hold the brakes with a button on the line, instead of his foot.

Pure methyl alcohol produced by synthesis for use in Alcohol Dragsters and Alcohol Funnycars.

Produced specifically as a fuel for drag racing. It is the result of a chemical reaction between nitric acid and propane.

When a driver is approximately seven inches behind the starting line and the small yellow light atop his or her side of the tree is illuminated.

Pro Tree:
Used in Top Fuel, Funny Car, Pro Stock, Pro Mod, Pro Stock Bike, Alcohol Dragster, Alcohol Funny Car, Super Comp, Super Gas, and Super Street, which features heads-up competition. All three large amber lights on the Tree flash simultaneously, followed four-tenths of a second later by the green starting light. A perfect reaction time on a Pro Tree is .400

Reaction Time (R/T): or "light".
Reaction time (R/T) indicates how much delay occurs from the last yellow light being turned on and the car starting the Elapsed Time timer, measured in thousandths of a second. The green light is turned on .500 seconds (.400 on Pro tree) after the last yellow, so a R/T value of .500 indicates a 'perfect light'. A value less than .500 indicate the car started before the green light, which is an illegal start activating the Red light. R/T values greater than .500 indicate how much delay occurred from the Green light coming on to when the car started. The larger the delay the greater opportunity for an opponent to start before you and gain an advantage.

Red-Lighting: or "bulb"
A red-light occurs if a car starts before the green light comes on. During competition, this will immediately give the win to the opponent. Racer's will often say, "He bulbed it away", meaning he lost because he red-lighted.

Rollout Time:
The time it takes for the car to leave the stage beam from a standing start. The Rollout time is dependant on the car's front tire size and where the car is initially staged.

Revolutions per minute is a measure of engine speed as determined by crankshaft spin. RPM is usually measured off the firing of a spark plug.

Sand bagging:
This is the practice of dialing-in an ET that is much slower than the ET's that your car runs so that you should always hit the finish line first. In order to be an effective sandbagger, you usually must have a better reaction time than your opponent, and then hit the finish line just before your opponent to avoid breaking out.

Stage and Pre-Stage:
Each competitor is required to line-up their car at the starting line. The starting line consists of a light beam which is about one inch off the ground. Once a car moves forward enough for its front tire to block the beam from reaching the other side, the car is considered "staged". Once both cars have staged, the calibrated countdown (see Christmas Tree) may begin at any time. To assist drivers in staging, a 'pre-stage' beam is also used. This beam is located a few inches behind the 'Stage' beam. This lets the drivers know when they are getting close to the stage beam.

Sixty-foot Time:
The time it takes the car to cover the first 60 feet of the racetrack. It is the most accurate measure of the launch from the starting line, which in most cases determines how quick the rest of the run will be.

Slider Clutch:
A multi-disc clutch designed to slip until a pre-determined RPM is reached, it also decreases shock load to the drive wheels.

Speed Trap:
The final 66 feet to the finish line, known as the speed trap, where speed is recorded.

The supercharger, or blower, is a crank-driven air-to-fuel mixture compressor. It increases atmospheric pressure in the engine, resulting in added horsepower.

The finish line area: this is where the bracket racer has to make his decision as to what tactics he is going to use to try to win the race. Will he need to hit the brakes?. Will his opponent?.

A trans-brake is a device which allows a car to remain stationary even when under power. It works by placing the transmission in 1st gear and reverse at the same time. Since both gears have the same ratio, but in opposite direction, the car cannot move. The trans-brake can be released with a button, which releases the reverse gear. Although they make for powerful launches, trans-brakes can be hard on the transmissions.

Trap speed:
Trap speed refers to a car's MPH measured during the last 60 feet of the ¼ mile. By knowing the weight of a car, the trap speed is a good indicator of how much horsepower an engine is making.

The turbocharger, is an exhaust gas-driven air-to-fuel mixture compressor. It increases atmospheric pressure in the engine, resulting in added horsepower.

A two-step is an electrical ignition device that will "cut out" cylinders at random, after the engine RPM tries to exceed a certain point. This is basically a rev-limiter. The driver can set the low-side RPM of the two-step, to be his launch rpm. With this, the driver can activate the two-step, and press the gas to the floor without over-revving the engine. You can recognize a two-step by the uneven pop-pop-pop- of the motor. Release the two-step and the motor is unleashed, the throttle already wide open.

An engine with a wedge combustion chamber, a combustion chamber resembling a wedge in shape. Wedge shaped pistons need not have parallel intake and exhaust valve stems.

Weight Transfer:
Weight transfer is critical to traction. Vehicles are set up to provide a desired weight transfer to rear wheels. When the vehicle accelerates, the front wheels lift and the weight shifts to the rear wheels, which makes them less likely to spin (in rear wheel drive cars).

Wheelie Bars:
Used to prevent excessive front-wheel lift.

This glossary can also be seen on the Official  NHRA website.