Top Fuel racing is a class of
drag racingDrag racing is a competition in which specially prepared automobiles or motorcycles compete two at a time to be the first to cross a set finish line, from a standing start, in a straight line, over a measured distance, most commonly a ¼-mile straight track....
in which the cars are run on a mix of approximately 90%
nitromethaneNitromethane is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent...
and 10%
methanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
(also known as racing alcohol) rather than
gasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
or simply methanol. The cars are purpose-built for drag racing, with an exaggerated layout that in some ways resembles open-wheel circuit racing vehicles. However, top fuel dragsters are much longer, much narrower, and are equipped with large tires in back and small tires in front, all in order to maximize their straight-line acceleration and speed.
Top fuel dragsters are the fastest category of drag racers, with the fastest competitors reaching speeds of 330 mph (531 kmh) and finishing quarter mile (402 m) runs in less than 4.5 seconds and 1,000 foot races in under 3.8 seconds. The raw speed and power of these cars is such that, at some events, races are run over 1000-foot (304m) distances rather than the traditional 1320 foot quarter mile, particularly when races are held at locations with insufficient room for cars to slow down after having completed the race.
This practice was instituted by the National Hot Rod Association (NHRA) following the fatal crash of driver
Scott KalittaScott Kalitta was an American drag racer who competed in the Funny Car and Top Fuel classes in the National Hot Rod Association Full Throttle Drag Racing Series. He was killed at Old Bridge Township Raceway Park, after an accident during qualifying...
. Kalitta was killed in an accident while qualifying for an NHRA event held at
Old Bridge Township Raceway ParkOld Bridge Township Raceway Park, originally known as Madison Township Raceway Park, is an American auto racing facility. It is located on 230 Pension Road in Old Bridge Township, near Englishtown, New Jersey, just off of County Route 527...
in Englishtown, NJ, in June 2008. Other sanctioning bodies still commonly use the longer 1320 ft (402 m) distance, although the FIA has, on occasion, used the shorter distance when venues have lacked sufficient "shutdown area."
A top fuel dragster accelerates from a standstill to 100 mph (160 km/h) in as little as 0.7 seconds (less than one fifth the time required by a production Porsche 911 Turbo to reach 60 mph) and can exceed 280 mph (450 km/h) in just 660 feet (0.2 km). This acceleration subjects the driver to an average force of about 4.0 G over the duration of the race.
Facts about Top Fuel
Before their run, racers often perform a
burnout in order to clean and heat tires. Additionally, the burnout applies a layer of fresh rubber to the track surface, which greatly improves traction during launch. A burnout may cover up to one quarter of the track's distance.
At maximum throttle and RPM, the exhaust gases escaping from a dragster's open
headersIn automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.In contrast, an inlet manifold is the part of an engine...
produce about 800–1000
poundsThe pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(3.6 kilonewtons) of
downforceDownforce is a downwards thrust created by the aerodynamic characteristics of a car. The purpose of downforce is to allow a car to travel faster through a corner by increasing the vertical force on the tires, thus creating more grip....
. The massive foil over and behind the rear wheels produces much more, peaking at around 12,000 lb
f (53 kN) when the car reaches a speed of about 324 mi/h.
The engine of a Top Fuel dragster generates around 150 dB of sound at full throttle, enough to cause physical pain or even permanent damage. A sound that intense is not just heard, but also felt as pounding vibrations all over one's body, leading many to compare the experience of watching a Top Fuel dragster make a pass to 'feeling as though the entire drag strip is being bombed'. Prior to a run, race announcers usually advise spectators to cover or plug their ears. Ear plugs and even earmuffs are often handed out to fans at the entrance of a Top Fuel event.
Dragsters are limited to a maximum length of 300 inches.
The fuel
NHRA regulations limit the composition of the fuel to a maximum of 90%
nitromethaneNitromethane is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent...
(as of 2008); the remainder is largely
methanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
. However, this mixture is not mandatory, and less nitromethane may be used if desired.
Kenny BernsteinKenny Bernstein is an American drag racer and former NASCAR and IndyCar team owner. He is nicknamed the "Bud King" for his success in the Budweiser King dragster, he has also been nicknamed "The King of Speed," because he was the first driver to break 300 miles per hour in the standing-start...
was the first drag racer in NHRA history to break 300 mi/h in such a class of car on the 1/4 mile in March, 1992.
While nitromethane has a much lower energy density (11.2 MJ/kg) than either gasoline (44 MJ/kg) or methanol (22.7 MJ/kg), an engine burning nitromethane can produce up to 2.3 times more power than an engine burning gasoline. This is made possible by the fact that, in addition to fuel, an engine must burn air in order to generate force: 14.7 kg of air is required to burn one kilogram of gasoline, compared to only 1.7 kg of air for one kilogram of nitromethane. This means that an engine can burn 8.7 times more nitromethane than gasoline.
Nitromethane also has a high temperature of vaporization, meaning that it will absorb substantial engine heat as it vaporizes, providing an invaluable cooling mechanism. The laminar
flame speedThe flame speed is the measured rate of expansion of the flame front in a combustion reaction. Whereas flame speed is generally used for a fuel, a related term is explosive velocity, which is the same relationship measured for an explosive. Combustion engineers differentiate between the laminar...
and combustion temperature are higher than gasoline at 0.5 m/s and 2400 °C respectively. Power output can be increased by using very rich air fuel mixtures. This is also something that helps prevent pre-ignition, something that is usually a problem when using nitromethane.
Due to the relatively slow burn rate of nitromethane, very rich fuel mixtures are often not fully ignited and some remaining nitromethane can escape from the exhaust pipe and ignite on contact with atmospheric oxygen, burning with a characteristic yellow
flameA flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...
. Additionally, after sufficient fuel has been combusted to consume all available oxygen, nitromethane can combust in the absence of atmospheric oxygen, producing
hydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, which can often be seen burning from the exhaust pipes at night as a bright white flame. In a typical run the engine can consume as much as 103 litres (22.75 gallons) of fuel during warmup, burnout, staging, and the quarter-mile run.
Rules
Like many other motor sport formulas originating in the United States, NHRA-sanctioned drag racing favors heavy restrictions on engine configuration, sometimes to the detriment of technological development. In some regards, teams are forced to use technologies that may be decades old, resulting in cars that may seem substantially less advanced than the average family car. However, while some basic facets of engine configuration are heavily restricted, other technologies, such as fuel injection, clutch operation, ignition, and car materials and design, are under constant development.
NHRA competition rules limit the
engine displacementEngine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...
to 500 cubic inch (8194 cc). A 4.1875 in. (106.4 mm) bore with a 4.5 in. (114.3 mm) stroke are customary dimensions. Larger bores have been shown to weaken the cylinder block.
Compression ratioThe 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
is about 6.5:1, as is common on engines with overdriven
superchargerA supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
s (that is, the supercharger is driven faster than the crankshaft).
Engine
The engine used to power a Top Fuel drag racing car has its roots in the second generation Chrysler Hemi 426 "Elephant Engine" made 1964-71. Although the Top Fuel engine is built exclusively of specialist parts, it retains the basic configuration with two valves per cylinder activated by pushrods from a centrally-placed camshaft. The engine has hemispherical combustion chambers, a 90 degree V angle; 4.8 in. bore pitch and a .54 in. cam lift. The configuration is identical to the overhead valve, single camshaft-in-block "Hemi" V-8 engine which became available for sale to the public in selected Chrysler Corporation (Chrysler brand) automotive products in 1950 (model year 1951).
The
blockA cylinder block is an integrated structure comprising the cylinder of a reciprocating engine and often some or all of their associated surrounding structures...
is machined from a piece of
forgedForging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...
aluminium. It has press-fitted, ductile iron liners. There are no water passages in the block, which adds considerable strength and stiffness. The engine is cooled by the incoming air/fuel mixture. Like the original Hemi, the racing cylinder block has a long skirt (to reduce piston "rocking" at the lower limit of piston travel). There are five main bearing caps, which are fastened with aircraft-standard-rated steel studs, with additional reinforcing main studs and side bolts. There are three approved suppliers of these custom blocks.
The
cylinder headIn an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...
s are machined from aluminum
billetsSemi-finished casting products are intermediate castings produced in a foundry that need further processing before being a finished good. There are four types: ingots, billets, blooms, and slabs.-Ingot:...
. As such, they, too, lack water jackets and rely entirely on the incoming air/fuel mixture for their cooling. The original Chrysler design of two large valves per cylinder is used. The intake valve is made from solid
titaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
and the exhaust from solid
Nimonic 80ANimonic is a registered trademark of Special Metals Corporation that refers to a family of nickel-based superalloys. Nimonic alloys typically consist of more than 50% nickel and 20% chromium with additives such as titanium and aluminium. The main use is in gas turbine components and extremely high...
or similar. Seats are of
ductile ironDuctile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spherulitic graphite cast iron and SG iron, is a type of cast iron invented in 1943 by Keith Millis...
.
Beryllium-copperBeryllium copper , also known as copper beryllium, beryllium bronze and spring copper, is a copper alloy with 0.5—3% beryllium and sometimes with other alloying elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has excellent metalworking, forming...
has been tried but its use is limited due to cost. Valve sizes are around 2.45 in. (62.2 mm) for the intake and 1.925 in. (48.9 mm) for the exhaust. In the ports there are integral tubes for the push rods. The heads are sealed to the block by copper gaskets and
stainless steelIn metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
o-ringAn O-ring, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a disc-shaped cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.The O-ring...
s. Securing the heads to the block is done with aircraft-rated steel studs.
The camshaft is billet steel, made from 8620 carbon steel or similar. It runs in five oil pressure lubricated bearing shells and is driven by gears in the front of the engine. Mechanical roller lifters ride atop the cam lobes and drive the steel push rods up into the steel rockers that actuate the valves. The rockers are of roller type on the intake side, but high exhaust pressure limits their use to the intake side only. The steel roller rotates on a steel roller bearing and the steel rocker arms rotate on a pair of titanium shafts within bronze bushings. Intake rockers are billet while the exhausts are investment cast. The dual valve springs are of coaxial type and made out of titanium. Valve retainers are also made of titanium, as are the rocker covers.
Billet steel
crankshaftThe crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
s are used; they all have a cross plane a.k.a. 90 degree configuration and run in five conventional bearing shells. 180 degree crankshafts have been tried and they can offer increased power, even though the exhaust is of open type. A 180 degree crankshaft is also about 10 kg lighter than 90 degree crankshaft, but they create a lot of vibration. Such is the strength of a top fuel crankshaft that in one incident, the entire engine block was split open and blown off the car during an engine failure, and the crank, with all eight connecting rods and pistons, was left still bolted to the clutch.
PistonA piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...
s are made of forged aluminium. They have three
ringA piston ring is a split ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine.The three main functions of piston rings in reciprocating engines are:...
s and aluminium buttons retain the 1.156 x 3.300 in. steel pin. The piston is anodized and
TeflonPolytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon....
coated to prevent galling during high temperature operation. The top ring is an L-shaped Dykes ring that provides a good seal during combustion but a second ring must be used to prevent oil from entering the combustion chamber during intake strokes as the Dykes-style ring offers less than optimal combustion gas sealing. The third ring is an oil scraper ring whose function is helped by the second ring.
The
connecting rodIn a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion....
s are of forged aluminium and do provide some shock damping, which is why aluminum is used in place of titanium, because titanium connecting rods transmit too much of the combustion impulse to the big-end rod bearings, endangering the bearings and thus the crankshaft and block. Each con rod has two bolts, shell bearings for the big end while the pin runs directly in the rod.
Superchargers
The
superchargerA supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
is a 14-71 type Roots blower. It has twisted lobes and is driven by a toothed belt. The supercharger is slightly offset to the rear to provide an even distribution of air. Absolute manifold pressure is usually 3.8-4.5 bar (56-66 PSI), but up to 5.0 bar (74 PSI) is possible. The manifold is fitted with a 200 psi burst plate. Air is fed to the compressor from
throttleA throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases , but usually decreased. The term throttle has come to refer, informally and incorrectly, to any mechanism by which...
butterflies with a maximum area of 65 sq. in. At maximum pressure, it takes approximately 900 hp to drive the supercharger.
These superchargers are in fact derivatives of
General MotorsGeneral Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
scavenging-air blowers for their two-cycle
diesel engineA diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s, which were adapted for automotive use in the early days of the sport. The model name of these superchargers delineates their size – the once commonly used 6-71 and 4-71 blowers were designed for General Motors diesels having six cylinders of 71 cubic inches each, and four cylinders of 71 cubic inches each, respectively. Thus, the currently used 14-71 design can be seen to be a huge increase in power delivery over the early designs.
Mandatory safety rules require a secured Kevlar-style blanket over the supercharger assembly as "blower explosions" are not uncommon. The absence of a protective blanket exposes the driver, team and spectators to shrapnel in the event that nearly any irregularity in the induction of the air/fuel mixture, the conversion of combustion into rotating crankshaft movements, or in the exhausting of spent gasses is encountered.
Oil and fuel systems
The oil system has a wet sump which contains 16 quarts of SAE 70 mineral or synthetic racing oil. The pan is made of titanium or aluminium. Titanium can be used to prevent oil spills in the event of a blown rod. Oil pressure is somewhere around 160–170
PSI-Alphabetic letters:* Psi 23rd letter of the Greek alphabet* Psi , a letter of the early Cyrillic alphabet, adopted from Greek-Mathematics:* Tangential angle of a curve*Chebyshev function*Dedekind psi function*Digamma function...
during the run, 200 PSI at start up, but actual figures differ between teams.
Fuel is injected by a constant flow injection system. There is an engine driven mechanical fuel pump and about 42 fuel nozzles. The pump can flow 100 gallons per minute at 8000 rpm and 500 PSI fuel pressure. In general 10 injectors are placed in the injector hat above the supercharger, 16 in the intake manifold and two per cylinder in the cylinder head. Usually a race is started with a leaner mixture, then as the clutch begins to tighten as the engine speed builds, the air/fuel mixture is enriched. As the increased engine speed builds up pump pressure, the mixture is made leaner to maintain a predetermined ratio that is based on many factors, one of which is primary one of race track surface friction. The
stoichiometryStoichiometry is a branch of chemistry that deals with the relative quantities of reactants and products in chemical reactions. In a balanced chemical reaction, the relations among quantities of reactants and products typically form a ratio of whole numbers...
of both
methanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
and
nitromethaneNitromethane is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent...
is considerably greater than that of racing gasoline, as they have oxygen atoms attached to their carbon chains and gasoline does not. This means that a "fueler" engine will provide power over a very broad range from very lean to very rich mixtures. Thus, to attain maximum performance, before each race, by varying the level of fuel supplied to the engine, the mechanical crew may select power outputs barely below the limits of tire traction. Power outputs which create tire slippage will "smoke the tires" and the race is often lost.
Ignition and timing
The air/fuel mixture is ignited by two 14 mm
spark plugA spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed fuels such as aerosol, gasoline, ethanol, and liquefied petroleum gas by means of an electric spark.Spark plugs have an insulated central electrode which is connected by...
s per cylinder. These plugs are fired by two 44-
ampereThe ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
magnetosA magneto is an electrical generator that uses permanent magnets to produce alternating current.Magnetos adapted to produce pulses of high voltage are used in the ignition systems of some gasoline-powered internal combustion engines to provide power to the spark plugs...
. Normal
ignition timingIgnition timing, in a spark ignition internal combustion engine , is the process of setting the angle relative to piston position and crankshaft angular velocity that a spark will occur in the combustion chamber near the end of the compression stroke...
is 58-65 degrees BTDC. (This is dramatically greater spark advance than in a petrol engine as "nitro" and alcohol burn far slower.) Directly after launch the timing is typically decreased by about 25 degrees for a short time as this gives the tires time to reach their correct shape. The ignition system limits the engine speed to 8400 rpm. The ignition system provides initial 50,000 volts and 1.2 amperes. The long duration spark (up to 26 degrees) provides energy of 950 millijoules. The plugs are placed in such a way that they are cooled by the incoming charge. The ignition system is not allowed to respond to real time information (no computer-based spark lead adjustments), so instead a timer-based retard system is used.
Exhaust
The engine is fitted with eight individual open exhaust pipes, 2.75" in diameter and 18" long. These are made of
steelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
and fitted with
thermocoupleA thermocouple is a device consisting of two different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a...
s for measuring of the exhaust temperature. They are called "zoomies" and exhaust gases are directed upward and backwards. Exhaust temperature is about 500°F (260°C) at idle and 1796°F (980°C) by the end of a run. During a nighttime event, the slow-burning nitromethane can extend flames many feet out from the exhaust pipes.
The engine is warmed up for about 80 seconds. After the warm up the valve covers are taken off, oil is changed and the car is refueled. The run including tire warming is about 100 seconds which results in a "lap" of about three minutes. After each lap, the entire engine is disassembled and examined, and worn or damaged components are replaced.
Performance
Measuring the power output of a top fuel engine directly is not always feasible. Certain models use a torque sensor incorporated as part of the RacePak data system. Dynamometers that can measure the output of a Top Fuel engine exist; however, the main limitation is that a Top Fuel engine cannot be run at its maximum power output for more than 10 seconds without overheating or possibly destroying itself explosively. The engine power output can also be calculated based upon the car's weight and its performance. The calculated
PowerIn thermodynamics, motive power is an agency, as water or steam, used to impart motion. Generally, motive power is defined as a natural agent, as water, steam, wind, electricity, etc., used to impart motion to machinery; a motor; a mover. The term may also define something, as a locomotive or a...
output of these engines is most likely somewhere between 8500 and 10,000
horsepowerHorsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
(approximately 4500-6000 kilowatts), with a
torqueTorque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
output of approximately 6000 lbf·ft (8135 N·m) and a
brake mean effective pressureThe mean effective pressure is a quantity related to the operation of an reciprocating engine and is a valuable measure of an engine's capacity to do work that is independent of engine displacement. When quoted as an indicated mean effective pressure or imep , it may be thought of as the average...
of 80–100 bar (8.0-10 MPa).
For the purposes of comparison, a 2010
Bugatti Veyron Super SportThe Bugatti Veyron EB 16.4 is a mid-engined grand touring car. The Super Sport version is the fastest road-legal production car in the world, with a top speed of . The original version has a top speed of...
, the world's most powerful production automobile at the time, produces 1184 bhp of power and 1106 lb
f·ft (1500 N·m) of torque.
Engine weight
- Block with liners 187 lbs (85 kg)
- Heads 40 lbs (18 kg) each
- Crankshaft 81.5 lbs (37 kg)
- Complete engine 496 lbs (225 kg)
Mandatory safety equipment
Much of organized drag-racing is sanctioned by the National Hot Rod Association. Since 1955, the Association has held regional and national events (typically organized as single elimination tournaments, with the winner of each two car race advancing) and has set rules for safety, with the more powerful cars requiring ever more safety equipment.
Typical safety equipment for contemporary top fuel dragsters: full face helmets with fitted
HANS deviceThe HANS device is a safety item compulsory in many car racing sports...
s; multi-point, quick release safety restraint harness; full body fire suit made of
NomexNomex is a registered trademark for flame resistant meta-aramid material developed in the early 1960s by DuPont and first marketed in 1967.- Properties:...
or similar material, complete with face mask, gloves, socks, shoes, and outer sock-like boots, all made of fire-resistant materials; on board fire extinguishers; kevlar or other synthetic "bullet-proof" blankets around the superchargers and clutch assemblies to contain broken parts in the event of failure or explosion; damage resistant fuel tank, lines, and fittings; externally accessible fuel and ignition shut-offs (built to be accessible to rescue staff); braking parachutes; and a host of other equipment, all built to the very highest standards of manufacturing. Any breakthrough or invention that is likely to contribute to driver, staff, and spectator safety is likely to be adopted as a mandated rule for competition. The 54-year history of NHRA has provided hundreds of examples of safety upgrades.
In 2000, the NHRA mandated the maximum concentration of nitromethane in a car's fuel be no more than 90%. In the wake of a
Gateway International RacewayGateway Motorsports Park is a race track in Madison, Illinois, USA, just east of St. Louis, Missouri. After being shuttered by former owner Dover Motorsports Inc., on Nov. 3, 2010, it was announced Sept. 8, 2011, that the facility would re-open and host an NHRA Full Throttle Series event Oct. 5-7,...
fatality in 2004, involving racer
Darrell RussellDarrell Russell was an NHRA drag racer. He was the 2001 NHRA Rookie Of The Year. At the time, he was only the third driver to win in his Professional debut....
, the fuel ratio was reduced to 85%. Complaints from teams in regards to cost, however, has resulted in the rule being rescinded starting in 2008, when the fuel mixture returns to 90%, as NHRA team owners, crew chiefs, and suppliers complained about mechanical failures that can result in oildowns or more severe crashes caused by the reduced nitromethane mixture.
The NHRA also mandated that different rear tires be used (in both Top Fuel
DragsterDrag racing is a competition in which specially prepared automobiles or motorcycles compete two at a time to be the first to cross a set finish line, from a standing start, in a straight line, over a measured distance, most commonly a ¼-mile straight track....
{TFD} and Top Fuel
Funny CarFunny Car is a drag racing car class. In the United States, other "professional" classes are Top Fuel, Pro Stock, and Pro Stock Motorcycle. Funny cars have forward-mounted engines and carbon fiber automotive bodies over the chassis, giving them an appearance vaguely approximating manufacturers'...
{TF/FC}) to try to prevent them from failing, and that a titanium "shield" be attached around the back-half of the roll-cage in Top Fuel Dragsters (although some Funny Car teams adopted this) to prevent any debris from entering the cockpit. This also was the result of the fatal crash at Gateway International Raceway. The rear tire pressure is also heavily regulated by Goodyear Tire and Rubber on behalf of the NHRA, at 7psi, the absolute minimum pressure allowed.
At present, final drive ratios higher than 3.20 (3.2 engine rotations to one rear axle rotation) are prohibited, in an effort to limit top speed potential, thus reducing the perceived level of danger.
External links