Bracket racing

Goal

The effect of the bracket racing rules is to place a premium on consistency of performance of the driver and car rather than on raw speed, which in turn makes victory much less dependent on large infusions of money, and more dependent on mechanical and driving skill, such as reaction times, shifting abilities, and ability to control the car. Therefore, bracket racing (using the aforementioned handicapping system) is popular with casual weekend racers. Some will even drive their vehicles to the track, race them, and then simply drive them home.

This format allows for a wide variety of cars racing against each other. While traditional drag racing separates cars into a wide variety of classes based on power and weight, bracket racing classes can be simpler, and can accommodate any vehicle with basic technical/safety inspection. Race events organized in this way are sometimes called "run-what-ya-brung".

Dial-in

Each car chooses a dial-in time before the race, predicting the elapsed time the driver estimates it will take his or her car to cross the finish line. This is usually displayed on one or more windows so the starter can adjust the "christmas tree" starting lights accordingly. The slower car in the race is given the green light before the faster car by a margin of the difference between their two dial-in times.

In principle, if both drivers have equal reaction times and their cars run exactly their posted dial-ins, both cars should cross the finish line at precisely the same time. In reality, this is an extremely rare occurrence. Measuring devices both at the start and at the end of the track post times down to 1/100000 of a second (0.00001s precision), which makes tied races almost impossible.

Some forms of bracket racing (NHRA Competition Eliminator, NHRA Stock groups) have cars classified by type, and the dial-in time is based on the type of car that is entered.

Reaction time

When a car leaves the starting line, a timer is started for that car. The difference between when the green light comes on and when the car actually leaves the starting line is called the reaction time. If a driver leaves before the light turns green, he is automatically red-lighted and disqualified for that round unless the opponent commits a more serious violation (crossing a track boundary line, timing block, or touching the barrier). In a drag race event with a heads-up situation, when the first driver commits a red light foul, the green light automatically turns on for the other driver. In a handicap start, if both drivers leave ahead of the green light, the driver with the worse aggravation will have the lane subsequently charged with the foul. The winner by default is the one who performed the lesser aggravation (-0.003 wins over -0.009, for example).

Sometimes, people incorrectly refer "reaction time" to the unrelated 60 foot takeoff time. The reaction time is merely an indication of how fast a driver reacted compared to when the green light came on. The 60 foot takeoff time is an indicator of how fast the vehicle started moving at the beginning of the race, regardless of the driver’s reaction time. If the driver launched the car with too much power for the available traction, he will have wheelspin and correspondingly will have a longer time to cross the 60 foot barrier if he were to drive with more finesse.

Breaking out

Breaking out is when a racer manages to cross the finish line in less time than the one he dialed-in beforehand.

Examples:

This eliminates any advantage from bending the rules by putting a slow dial-in time on the windshield to get a head start. However, some racers will purposely dial a slower time and then let off of the throttle or use their brakes near the end of the track in an attempt to use strategy to win the race rather than relying on the car to run the dial in.

Bracket Racing Strategy

Bracket racing boils down mainly into one thing; putting up the best "package". The best package is technically the winner in every drag race. A "package" is : package = drivers reaction time + deviation from the dial-in.
For Example:
Driver A has a reaction time of .025 and his car runs 9.653 on a 9.64 dial in. His package = .025 + (9.653-9.64) = .038
Driver B has a reaction time of .005 and his car runs 10.684 on a 10.66 dial in. His package = .005 + (10.684-10.66) = .029

In this scenario driver B wins despite his car running further off the number. But we can deduce even more than just that he won; we can see that he won by a (.038 - .029) = .009 finish margin which is about 22 inches at about 140 mph.
The formula used to calculate the margin of victory is :

17.6 * finish margin * behind vehicle mph = finish margin in inches

Professional(and some amateur) Bracket Racing has evolved over the years into a drivers sport. It used to consist of trying to get a good reaction time then hoping the car ran near the number. Drivers would avoid breaking out like the plague, dialing their car's .01 faster than it had ever gone before.
Now it has turned into a chess match between two drivers, guessing each other's next move. The race starts in the staging lane where you get ready to race, where you decide what dial in to put on your car. This is arguably the most important part of a bracket race : making sure you can "run the number". In other words, make sure you can go as fast as your dial in says you can. Everyone has a different strategy, but any strategy has its flaws and can be beaten; that why the best strategy is one that includes many different strategies and cannot be predicted.

Red Light and other fouls

If a car leaves the starting line before the green light comes on, a foul is recorded (a red-light start), and that car is provisionally disqualified. Traditionally, only the first car to foul start is shown the red light; an automatic green light is shown in the other lane at the appropriate time. Starting in 2016 in selected races, a new programming function will initially show a green light to the first car, even if the driver committed a foul start. Once the second driver leaves, only the driver whose reaction time was worse, provided the reaction time is negative (meaning a foul start), will have their lane subsequently show a red light (left lane -.021 and right lane -.020, red light on the left lane only). Another form of foul is to cross the dividing line between the two lanes, or the line at the edge of the racing surface, both of which negates a red light foul. A foul is worse than a break out; one car can break out but if the other car fouls, the car that breaks out advances to the next round. If both cars foul, the lesser of the violations is the winner; a break-out is the least serious violation, then a red light, crossing the boundary line at the edge of the surface, crossing the dividing line between the lanes, and then leaving before the tree is started.

Both cars are disqualified in double fouls if both competitors cross either boundary line (edge of surface or dividing lane between lanes). Only one car is disqualified if both competitors commit different fouls of the other type. Both drivers are disqualified if they leave before the tree is started, but if video evidence can show which of the two drivers left first, only the first driver is disqualifed. In a double disqualification in the final on boundary lines, only the first driver to cross the boundary line will be tagged.