Top Fuel is the fastest class of many classes competing on the national level. The vehicles bear no resemblance to any conventional automobile except the number of wheels but are still considered “race cars”. Each Top Fuel car represents a large investment that goes well beyond the car itself. This large investment includes the vehicle, spare parts, a highly trained full-time race track crew and additional staff operating in a large home base shop. In this shop the staff maintains the car and transporter between races and performs development work to maintain the team's competitiveness.
The designation “Top Fuel” originated in the early years of organized drag racing. As racers began experimenting with methods to increase performance, the use of nitromethane and methanol as fuel delivered extreme improvements. Adding a supercharger also made dramatic performance increases. To take advantage of these enhancements, racers had to spend much more money. A separation between teams using exotic fuels and teams using gasoline produced significantly different race car styles. The gasoline-powered cars were not competitive against the exotic fueled cars.
Early sanctioning bodies established rules and class designations to separate the gasoline and exotic fuel camps. The fastest gasoline-powered vehicles were designated AA Gas Dragsters. (AA/GD) soon to be called Top Gas and the fastest exotic fueled vehicles were originally AA Fuel Dragsters (AA/FD) which eventually became Top Fuel (T/F). The Top Gas designation eventually fell aside as spectators showed an obvious preference for the violent action of the exotic fueled breed.
Double letters have always been used to designate supercharged classes.
Today, injected, nitro-fueled dragsters (without superchargers) compete as A Fuel dragsters (A/FD) in the TAD (Top Alcohol dragster) sportsman category against supercharged dragsters running alcohol (methanol) without nitro. (At one time these were called “Blown Alcohol Dragsters” or BAD)
The amount of prize money paid out to competitors at the race tracks will not come close to meeting the expenses of a top fuel team. The teams all rely on revenue from advertising contracts with sponsors and from various marketing endeavors centered around the race car and driver to pay expenses and hopefully deliver a profit to team owners. All the companies whose names appear on the race car have paid to have that name on the car. The placement and size of the sign determines how much the sponsor pays.
Top Fuel operations are the drag racing equivalent of Formula 1 teams - the best each sport has to offer to both sponsors and spectators. In the world there are probably less than one hundred active Top Fuel teams. Top fuel drivers are members of a very exclusive club. Top Fuel crew chiefs possess a unique set of skills in tuning and adjusting the subtle parameters of a brute force mechanical machine. Unlike formula 1, drag racing does not use real-time telemetry to collect data. Each Top fuel car has on-board data collection systems that are downloaded to computers after each pass down the drag strip. Crew chiefs use the collected data, in combination with their experience to make adjustments.
Semi-technical Information
Most drag racing fans have some grasp of the basic technical aspects of Top Fuel cars. After all the cars are designed and built for one very simple task: traversing 1000 feet (once a quarter mile) as quickly as possible from a standing start. The challenges of this task make it much harder to accomplish than it sounds. Each pass down the track is different. Air temperatures, track temperatures, track conditions, humidity, barometric pressures...etc change as the day progresses. The competition is always between two cars and the winner is the car that crosses the finish line first. The effects of changing conditions require subtle adjustments to several components, making the crew chief's skills and experience at least as important as the driver's.
The majority of early rules governing fuel drag racing were centered on safety. The violence of early fuel cars put drivers and spectators in danger. Safety rules continue to be the most important rules but certain standardized components and restrictions have become part of the rule books.
Engine size is now limited to 500 cubic inches displacement. Fuel is limited to 90% nitromethane. There is a minimum weight for the car/driver/fuel and there is a specified rear drive ratio. Tires are specified units built especially for top fuel racing. There are many other rules and specifications in the official rule books and every car is weighed and inspected after winning. There are some rules that make drag racing easier to watch and safer for all concerned. Some rules are intended to keep competition costs consistent so that less well funded teams can remain competitive. The very technical aspects found in Formula 1 racing are not permitted here. Telemetry, electronic traction controls, electronic fuel injection, electronic timers for clutch application and other advanced technology are not allowed. Crew chiefs and drivers have computers to look at data recorded during the runs but the cars are never controlled by computer systems.
Engines are specially constructed aluminum blocks equipped with the strongest components the teams can find or have made. All engines are conventional push-rod v-eight configuration . Overhead cams or other exotic configurations are not used. Cylinder heads are the same basic configuration that has been in use since the 1950s. The actual design and material has changed but each cylinder still has only two valves operated by rocker arms and push rods. Superchargers must meet certain specifications and the air inlet area is limited. NHRA has been trying to keep the speeds below 300MPH by adding restrictions (and shortening the race to 1000 feet from 1320 feet.) There are no cooling systems.
The engines are coupled to the rear end through a multi-disk, pneumatically controlled slip clutch. The trimming of the clutch application is one of the crew chiefs' primary tuning adjustments. Getting this adjustment wrong will cause the car to spin the tires severely or accelerate too slowly. Adjustments are made using pneumatic flow controls to manage when and how quickly the clutch stages are applied. At some point down the track, the clutch becomes fully engaged – sometimes welding itself together due to friction and heat.
Some other adjustments available to crew chiefs are ignition timing mapping, fuel mixture, supercharger overdrive ratio, tire pressure and even the percentage of nitromethane in the fuel (up to 90%). Every successful run depends on the crew chief hitting the combination that matches the conditions at the time of the run. Missing even one of these adjustments will mean loosing a race. Missing more than one adjustment or missing a major setting like clutch timing will likely mean a spectacular loss (tire smoke or explosion and fire.) Every mechanical component on the car is critical and operating at it's mechanical limit. A successful run destroys certain mechanical pieces like pistons that must be replaced every run. Their effective life is measured in seconds. There are some situations where a driver can save a run that would have otherwise be a loss.
The NHRA Top Fuel Dragster exists in a world of edges. The engines barely live 6 seconds at full throttle because they are at the edge between controlled and exploding. The tires are always right on the edge between slipping and gripping. The driver must always try to achieve a near perfect reaction time just at the edge between perfect and foul (a red light). Overall, the cars themselves are always on two edges: Going straight under driver's control or making some out of control move too quick for the driver to correct and keeping the front wheels on the track for steering control or flipping over backwards.
The world's fastest motorsport is the fastest because every person or thing involved is pushed right up against limits. It exists in a brute force world of controlled explosions and overstressed mechanicals. The super-high-tech world of formula 1 racing lives on technology and money. Top fuel drag racing lives in the hearts, minds and skillsets of the people involved.
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