If you are a hardcore racer, occasional fan, or first time spectator; here are some basics regarding the sand drag racing that you will see at National Sand Drag Association events:
Track
A sand drag racing track is 300 feet (100 yards) long, which is the same distance as a football field. The surface consists of a dirt/sand/clay mix that creates optimal traction for the sand drag racing vehicles. Track grooming is necessary to maintain a competitive and safe race surface for all competitors.
Basics
Sand drag racing is very similar to our asphalt drag racing counter parts. The major exceptions are obviously the surface and track distance. Many sand drag vehicles previously raced on asphalt and some are even dual-purpose cars set up to run in both types of drag racing.
Christmas Tree
The Christmas tree is the starting apparatus hooked to a high tech electronic timing system. 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 LED lights, a green bulb, and a red bulb. To understand how the system works, you have to understand that there is a series of electronic beams hooked to the timing system. As you will understand, the beams are what are used to time the cars and ensure a fair race.
The top bulb on each lane is the Pre-Stage indicator. When the racer’s car breaks the electronic beam that is six inches before the Stage beam, the Pre-stage light will illuminate. The racer will then move six inches forward to light the second light from the top on the tree, which indicates they have broken the Stage beam. The Stage beam is approximately 14” ahead of the Guard Beam. The Guard Beam is the start of the 300’ race track and will start the timers for the racer’s Elapsed Time as well as how close the racer reacts to the Green light (Reaction Time). Once in the stage beam, the racer will wait for the count down on the tree. The next three lights (yellow) indicate to the racer how soon the green light will come on. There are two types of tree countdowns that will be discussed in the next section. The second to the bottom light on the tree is the indication for the racer to go. If the racer trips the Guard Beam after it is time for the racer to go, then the Green light will illuminate. If the racer trips the Guard beam before it is his or her time to go, then the bottom bulb on the tree will light up, which is known as a red light. This is an infraction that in most cases results in disqualification. The racers will continue down track until they reach a series of electronic sensors. The first sensor is 280’ from the Guard Beam, this sensor is the start of the speed trap that calculates the average speed within the last 15’ of the 300’ long sand drag race track. The Finish Beam is exactly 300’ from the Guard Beam, this is the finish line. Elapsed Time (ET) is calculated from the Guard Beam to the Finish Beam. This sensor is also used in the calculation of the finish line speed, as stated above.
Tree Countdown
There are two different Tree Countdown scenarios. The first is called the Pro Tree; which is when the third, fourth, and fifth bulbs on the Christmas tree turn on for four-tenths of a second (.400) before it is a legal time for the racer to leave the starting line. The other tree countdown is called a Sportsman Tree. The Sportsman Tree is when each of the 3rd, 4th, and 5th bulbs on the tree turns for four-tenths of a second per bulb in sequence. This basically gives the driver a countdown of 1.2 seconds before they may legally leave the starting line.
Determining a Winner
The first vehicle across the finish line wins, unless, in applicable categories, it runs quicker than its dial-in or index. A racer also may be disqualified for leaving the starting line too soon, leaving the lane boundary (either by crossing the centerline, touching the guard wall or guardrail, or striking a track fixture such as the photocells), failing to stage, or failing a post-run inspection.
Professional Series
Top Fuel
The Top Fuel class is equivalent to the Top Fuel Dragsters you see on TV in NHRA competition. These Nitromethane burning, 8000 Horsepower, 25 feet long machines are the quickest accelerating machines on the Earth. They accelerate from 0-160 MPH in 2.3 seconds over the 300’ race course. There are virtually NO rules in this class besides safety considerations. Watch for the header flames from these Nitromethane burning machines at night. These are truly the Kings of the Sand.
Top Alcohol
The Top Alcohol class is the NHRA Top Alcohol Dragster of the sand. 
These high revving 3000 HP Methanol burning Dragsters can cover the 300’ course nearly as fast as their Top Fuel counterparts. This highly competitive category can see finishes decided in thousandths of a second (.001). One of the distinct differences from the Top Fuel dragsters is that the Top Alcohol dragsters often leave with their engines revved way up to around 7000 RPM as opposed to Top Fuel cars that leave from an idle. This is due to the clutch differences between the two types of cars. Keep an eye out for these Methanol burning machines.
Top Eliminator
Top Eliminator is a bit different from the Top Fuel and Top Alcohol categories in that it is an Index class. An Index class is where a racer tries to run a specified ET within going faster, which in this class’ case is 2.950. This category sees a wide variety of race cars competing on an even playing field; everything from Blown Methanol Funny Cars to Nitromethane Turbo Four-Cylinder Buggies to Naturally Aspirated Nitrous Injected Jeeps and everything in between. This diverse class sees some of the tightest racing in NSDA competition and finish line margins of mere inches. You won’t want to miss the Top Eliminator class as it is sure to be a crowd pleaser.
Super Eliminator
The Super Eliminator class is new for 2010 and very similar to the Top Eliminator category in that it is an Index class. The Index for Super Eliminator is 2.800 seconds. These cars are no slouches often topping 120MPH at the end of the 300’ race track. This offers a way for racers to race heads-up without spending a Top Fuel or Top Alcohol budget to go racing. These guys put on a great show with close racing and high action.
Pro Bracket Classes
In NSDA competition, there are Pro Bracket classes that make up the Sunday race program. These grassroots racers compete in the Pro 1, Pro 2, Pro 3, Motorcycle Pro 1, and Motorcycle Pro 2 categories. A bracket racing system is used consisting of dial-ins to create an even playing field and fierce competition. In these classes you will see everything from Dragsters to Buggies to Jeeps to ATV’s. If you want to see the best of the best bracket racers, these are the classes to watch.
Pro Specialty Classes
The NSDA has two Pro Specialty classes that run within Saturday’s race program. These are the Pro Mod and Pro Outlaw categories. Pro Mod is a heads-up, first to the finish line wins class designed for Jeeps, Trucks, and basically anything under 125” wheelbase. The limiting factor is the mandatory use of a Sand Tires Unlimited 20.00 paddle tire. This gives the racer the challenge of putting as much power down to the race track as possible with limited traction. These racers are truly some of the most entertaining to watch in NSDA competition. Pro Outlaw is a venue for Pro Bracket Racers from multiple classes battling it out in one big class during the Saturday show. You will see Jeeps, Dragsters, Buggies, and Trucks battling for the prestigious class win. These racers will put on a great show for all.
Sportsman Bracket Classes
There are four Sportsman classes in NSDA competition; Sportsman 1, Sportsman 2, Motorcycle Sportsman 1, and Motorcycle Sportsman 2. These are truly the entry level classes in sand drag racing competition. Low entry fees and a trophy only payout allow racers an opportunity to break into competition as well as learn bracket racing without breaking the bank. Bring out your sand car, Jeep, Truck, or ATV to compete in these classes with the best NSDA has to offer.
Junior Classes
The Junior divisions of the NSDA offer today’s youth an opportunity to learn how to race and have fun in bracket-style racing. The Junior Dragster category leads the Junior classes with advanced kids up to 16 years old racing in a safe environment. Youth categories are reserved for younger and novice racers to have fun along side all the best in the sport of sand drag racing. These classes are typically run on Sunday mornings at NSDA events.
Sand Drag Racing Terms
These are some words you may hear at a NSDA event and may wonder what the meaning of the word is.
Bigger Digger: A form of tire produced by Skat-Trak that is based on a drag racing slick with vulcanized “paddles” adhered on. The Bigger Digger is a long blade that spans the full width of the tire. These are typically used on Top Fuel Dragsters.
Breakout: Used only in handicap racing, “breakout” refers to a contestant running quicker than he or she “dialed” his or her vehicle (predicted how quick it would run). Unless the opponent commits a more serious foul (e.g., red-lights, crosses the centerline, or fails a post-race inspection), the driver who breaks out loses. If both drivers break out, the one who runs closest to his or her dial is the winner.
Christmas Tree: Also called the Tree, it is the noticeable electronic starting device between the lanes on the starting line. It displays a calibrated-light countdown for each driver.
Deep stage: to roll a few inches farther into the beams after staging, which causes the pre-stage lights to go out. In that position, a driver is closer to the finish line but dangerously close to a foul start.
Elapsed time: the time it takes a vehicle to travel from the starting line to the finish line. Also called E.T.
Eliminations: After qualifying, vehicles race two at a time, resulting in one winner from each pair. Winners continue in tournament-style competition until one remains.
Foul start: indicated by a red light on the Christmas Tree when a car has left the starting line before the green light, or starting signal.
Hemi: A Hemi engine has a hemispherical shaped cylinder-head combustion chamber, like a ball cut in half.
Holeshot: when a driver reacts quicker to the Christmas Tree to win a race against an opponent with a quicker E.T.
Hooker: A form of tire produced by Skat Trak that is based on a drag racing slick with vulcanized “paddles” adhered on. The Hooker is a blade that typically spans approximately ¾ of the width of the tire and is often staggered in placement on the tire. This style of tire is used on most high horsepower vehicles.
Methanol: pure methyl alcohol produced by synthesis; used in the Top Alcohol class as well as many other categories.
Nitromethane: Produced specifically as a fuel for drag racing, it is the result of a chemical reaction between nitric acid and propane.
Paddle Tire: A paddle tire is a rubber tire with "paddles" stretching across the full width of the tire that is produced from a mold. Sand Tires Unlimited and Xtreme Tire Company are the two most common manufacturers of paddle tires. Most moderate and lower horsepower vehicles as well as all ATV’s run this type of tire.
Pre-stage: to position the front wheels about seven inches behind the starting line so the small yellow lights atop that driver’s side of the Christmas Tree are glowing. The next step is to stage and be ready to race.
Pro Tree: All three large amber lights on the Christmas Tree flash simultaneously, followed four-tenths of a second later by the green starting light. This is used in heads-up competition.
Reaction Time: the time it takes a driver to react to the green starting light on the Christmas Tree, measured in thousandths of a second. The reaction-time counter begins when the last amber light flashes on the Tree and stops when the vehicle trips the guard beam.
Sixty-foot time: the time it takes a vehicle to cover the first 60 feet of the racetrack. It is the most accurate measure of the launch from the starting line and in most cases determines how quick the rest of the run will be.
Speed trap: the final 15 feet to the finish line where speed is recorded.
Sportsman Tree: A handicap starting system used to equalize competition. The three amber bulbs on the Christmas Tree flash consecutively four-tenths of a second apart, followed four-tenths later by the green starting light. A perfect reaction time on a full Tree is .000.
Stage: to position the front wheels right on the starting line so the small yellow lights below the pre-stage lights are glowing. Once both drivers are staged, the calibrated countdown (see Christmas Tree) may begin.
Supercharger: a crank-driven air/fuel-mixture compressor, also called a blower. It increases atmospheric pressure in the engine to produce more horsepower.
Super Scooper: A form of tire produced by Skat Trak that is based on a drag racing slick with vulcanized “paddles” adhered on. The Super Scooper is a blade that typically spans approximately ¾ of the width of the tire and is often staggered in placement on the tire. This style of tire is used on most high horsepower vehicles.
Wedge: an engine with a combustion chamber resembling a wedge in shape.
Wheelie bar(s): used to prevent excessive front-wheel lift.
Links:
[1] http://www.sand-drags.com/print/nsda-basics