These contests are started by means of an electronic device commonly called a Christmas tree because of its multicolored staging lights. On each side of the tree are seven lights; two small amber lights at the top of the fixture, followed in descending order by three larger amber bulbs, a green bulb, and a red bulb. .
Two light beams cross the starting-line area and connect to trackside photocells, which are wired to the Christmas Tree and the electronic timers in the control tower. When a cars front tire breaks the first light beam, called the prestage beam, the prestage light is illuminated on the Chrismass Tree to indicate to the racer that he or she is approximately seven inches from the starting line.
When the racer rolls forward into the stage beam, the front tires are exactly positioned on the starting line and the stage bulb is lit on the tree, indicating to both racers and to officials that the car is ready to run. When both cars are fully staged, the starter will activate the tree and the drivers will turn their attention to the three large amber lights that dominate the center of the Christmas Tree.
Depending on the type of racing, the Christmas Tree either will flash all three large amber lights simultaneouly, followed four-tenths of second later by the green light (called a Pro Tree), or will light the three bulbs consecutively five-tenths of a second apart, followed five-tenths of a second later by the green light (a full tree).
If a driver and/or his car react too quickly and the car leaves the starting line before the green light flashes, the red foul light will illuminate, signaling disqualification.
Two seperate performances are monitered for each run: the elapsed time and the speed. Upon leaving the staging beams, each vehicle activates a elapsed time clock which is stopped when the same vehicle reaches the finish line. The start to finish clocking is the vehicles elapsed time (E.T.), which serves to measure performance. Speed is measured in a 66-foot "speed trap" that ends at the finish line. Each lane is timed independently.
E.T.,Bracket and handicapped racing
Though some racers choose to race vehicles built to certain specifications to fit into a certain NHRA class (outlined in the NHRA rulebook), an evergrowing number of racers chooses to race on a local level in categories (or brackets) divided according to elapsed time , such as 0 to 9.99 seconds, 10.00 to 12.99 seconds, and so on. This form of racing offers a good starting point for the novice. However, thousands of drag racers enjoy E.T. racing so much that they have participated for many years.
Anytime two vehicles of different performance potentials race, they can do so evenly with handicap start. The anticipated elapsed times - refered to as a "dial-in" - for each vehicle are compared and the slower car receives a head start equal to the difference.
For example, car A has been timed at 15.98, 16.02 and 16.99 seconds for the quarter-mile, and the driver decides that a dial-in of 16.00 is appropriate. Meanwhile, the driver of car B has recorded elapsed times of 13.47, 13.52, and 13.56 on the same track and he has opted for a dial-in of 13.50. Accordingly, car A will get a 2.5 second head start over car B when the Christmas Tree counts down to each cars starting green light. This puts the emphasis on driver reaction.
Because the lanes are timed independantly and the elapsed time clock does not begin ticking until the vehicle moves, if both vehicles should run exactly on their dial-ins, the win will go to the driver who reacted quickest to the starting signal. that reaction to the starting line signal is called reaction time.
Reaction times are measured in thousandths of a second. The reaction time counter begins when the last yellow flashes on the Christmas Tree and stops when the race car clears the stage beam. (Although some reaction timers begin counting when the green light flashes, this is not the case in the majority of starting systems.) A perfect start - one in which the race car clears the beam at the very instant the green light flashes - will produce a .400 reaction time on a Pre Tree and a .500 on a full tree (the difference is due to the length of time between the final yellow light and the green light in the two sequences.) Reaction time also measure the amount of a red light violation. For example, if a pro Tree car leaves the starting line with a .390 reaction time (or .490 on a full tree), the driver will have fouled by .010 of a second.
Technique in staging and starting is one of the most vital skills of a E.T. racer because a majority of races are won or lost on the starting line. A driver with a quicker reaction time can overcome an opponents perfomance advantage - whether it's in a heads up race or if the opponent runs closer to his/her dial-in - and record the win. Because of this the vehicle may sometimes appear to have a mathematical advantage in comparative elapsed times but actually lose the race. This fact makes starting line reflexes extremely important in drag racing. Close observation and lots of practice pays off.
Breakouts and other disqualifications
Should a driver go quicker than their predetermined E.T. dial-in, it's a breakout, and grounds for disqualification. In the case of both vehicles running under their dial-ins, the win gos to the driver that runs closest to his/her dial-in. If both drivers violate their dial-ins by an equal amount, the winner is the driver who crossed the finish line first.
Other disqualifications include leaving the lane boundry (either by crossing the centerline, touching the wall or the guardrail or striking a track fixture, such as photocells.), failure to stage, and failure to pass a post-run inspection ( in NHRA class racing, usually this consists of a check of vehicle weight and fuel after each run and a complete engine teardown following an event victory).
NHRA employs a "first or worst" rule for disqualifications. A red light is considered worse than a breakout; crossing a lane boundary is worse than a red light, even though it may have occured after the red light; and all technical disqualifications supersede any on track disqualifications.
Who can compete?
Virtually anyone can compete in E.T. drag racing. Drivers are required to have valid state drivers license or NHRA competition license, and the vehicle must meet basic saftey criteria (i.e. have good brakes, be equiped with seatbelt and so on). This applies to most street type vehicles. Faster, all-out race cars must meet more stringent requirements as in outlined in the NHRA rulebook.
1964 Dodge Polara 500