Top fuel

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Two TF-Funny Cars in a night race. The so-called "header flames" are clearly visible

Under the term Top Fuel (class abbreviation TF) in " drag racing " (a type of motor sport which is about maximum acceleration) those vehicle types are summarized in which nitromethane (empirical formula CH 3 NO 2 ) is used as fuel. In dragsters with supercharging the chassis design is made between pursuant Top Fuel Dragster and Funny Car .

Dragsters with nitromethane injection without compressor charging are grouped as so-called "A-Fuelers" in the Top Methanol class . There they compete against vehicles that run on the less powerful methanol but with compressor assistance.

The as drag bikes designated motorcycles , there are the classes Top Fuel Bike (four-cylinder) and Top Fuel Super Twin (twin cylinder).

The widespread term “Nitro” (for nitromethane) should not be confused with “Nitrous” , the English abbreviation for Nitrous oxide (empirical formula N 2 O), which is used in nitrous oxide injection .

Top fuel dragster

Basic technical information on a TF dragster in "rear engine" design. For comparison, a "front engine" on the same scale.
Start of a Top Fuel Dragster at the Santa Pod Raceway.

Top Fuel Dragsters are uncompromising vehicles geared towards performance, traction, maximum straight-line stability and the safety regulations to be observed. In the early days of drag racing, the form of the front engine dragster dominated. The safety of the pilots was largely disregarded at the time. With the increasing performance and the increasing dangers of an "engine blow-up" (dt .: "burst engine") for the driver sitting directly behind, this configuration became a problem in the 1960s. Don Garlits , one of the leading protagonists of this time, developed the new concept of the engine installed behind the driver after a serious accident with his front engine. This construction also prevailed because of the additional positive effects on drivability. Today, the original “Front-Engine-TF” can only be seen at popular nostalgia events. In the USA, however, there is a series that retains the front engine concept in dragsters and equips the vehicles with modern engines, aerodynamic components and the latest safety systems.

  • Formerly "Fueler" from 1958

  • Front engine TF with the Keith Black engine, which was widely used at the time (second half of the 1960s)

  • TF dragster of the only German top fuel pilot and FIA champion 1997 Rico Anthes in the Museum Sinsheim.

  • Start of a Top Fuel Dragster (Jndia Erbacher, CH) in a race at the Rico Anthes Quartermile 2019.

Top Fuel Funny Car

Top Fuel Funny Car with body folded up (approx. 2008)

Top Fuel Funny Cars (class abbreviations FC or TFFC) have a significantly shorter wheelbase than the TF dragsters (3175 mm compared to 7620 mm). The body is a one-piece plastic cast (mainly carbon nowadays), which is often based on a US production vehicle. Common models are, for example, the Chevy Camaro Z 28 , Chevy Monte Carlo , Ford Mustang or the Dodge Charger . These "bodies" are completely folded up for the driver to get in and out of the vehicle and have been aerodynamically modified to such an extent that they are reminiscent of the underlying production model. The engine is placed in front of the driver, which together with the short wheelbase makes handling much more difficult and often leads to spectacular rides over the quartermile ; this fact ultimately gave the class its name.

The now mandatory covering of the engine with Kevlar fabric (so-called "explosive mats"), a massive protective plate between driver and engine, as well as on-board fire extinguishing systems now offer sufficient protection.

  • Nostalgia Funny Car
    (ca.1970s)

  • TF / FC by Don Prudhomme
    (1990)

  • Robert Hight in his 2012 JFR Ford Mustang Funny car

  • TF-Funny Car by John Force with Chevy Camaro Body (2017)

technology

Top fuel engine based on the Ford 427 SOHC. This engine was one of the most widely used TF engines in the front-engine dragsters of the 1960s / 70s
Connecting rods of a TopFuel Dragster and a Ferrari 458

Engines

To burn the fuel, conventional engines require the oxygen in the ambient air, which is supplied either via a carburetor or to increase performance via a turbocharger and compressor. The advantage of nitromethane is that it can burn without oxygen, according to the reaction 2 CH 3 NO 2 → 2 CO + 2 H 2 O + H 2 + N 2 . The resulting hydrogen burns in the outside air, which is why meter-long exhaust flames (so-called "header flames") occur.

The regulations limit the engine size of the TF dragsters and funny cars to a displacement of 500  cubic inches - that is 8193 cm³. The design of the engines is based on the Chrysler Hemi unit from the 1960s and is kept extremely simple - there is only one central camshaft that actuates two valves per cylinder via push rods. Because the evaporative cooling of the injected fuel is sufficient for cooling over the short racing distance, there are no water ducts in the engine block or cylinder heads, which increases the rigidity. The maximum output is approx. 6000 kW (approx. 8160 HP), the drive of the huge compressor alone consumes approx. 700 HP. The power required for this is achieved using a fuel with a mixture ratio of 90% nitromethane and 10% methanol and an engine charger . This also results in a corresponding consumption of around 1.5 gallons (5.7 l) per second under full load and around 10–12 gallons (rounded: 42 liters) for a complete race run (including burn-out ). At full load, the fuel pump delivers 64 gallons (242.26 liters) of fuel to the cylinders. The engines use up the electrodes of their two, sometimes three spark plugs per combustion chamber completely in one run, which is not a problem, because the engines start to "diesel" at the latest after half of the run due to the high compression and the extremely hot exhaust valves. d. H. the mixture ignites automatically as a result of the heat. When idling, these "nitro burners" can be recognized by the dry, hard exhaust noise. A Top Fueler starting at full throttle generates a sound pressure of around 150  dB , so that staying in the immediate vicinity is only possible with hearing protection. The compressor pushes the fuel-air mixture into the combustion chambers with an overpressure of up to 5 bar. For charged street cars, charging pressures of up to one bar or just above are common. At maximum engine speed, the exhaust gases from the open exhaust manifolds generate up to 3.6 kN contact pressure. The specially developed V8 engines are dismantled and checked after each run and some parts, e.g. B. Bearing, exchanged across the board.

Performance measurement

Thanks to the energy-rich fuel nitromethane and the enormous boost pressure, the engines are able to mobilize several thousand horsepower for a few seconds. The dragsters of the European teams generate between 6,000 and 7,000 hp. The maximum performance is adjusted to the grip of the track. The most powerful dragsters come from the USA, the country of origin of drag racing, and achieve outputs of more than 8,000 hp, those of the top teams up to 10,000 hp. Due to the short operating time, the maximum power is not exactly determined on an engine test bench , but is calculated as precisely as possible with the help of strain gauges in the drive train with the formula power = torque × speed .

tires

In racing, high demands are made on the tires, the demands in drag racing, especially on the rear wheels, are enormous. Currently (as of 2020) only one make of tire is approved for TF: The " Goodyear Eagle Dragway Special" This tire is certified up to 563 km / h.

The rear tires are huge at 36.0 × 17.5–16 and have a circumference of around 3 meters. They are designed so that they change in diameter and width with increasing speed. The static diameter of about 92 cm increases to 150 cm, while the width shrinks from 46 cm to about 26 cm. This effect leads to a “variable transmission ratio” in terms of speed (distance covered per tire revolution). The sidewalls of the tires are designed in such a way that they “fold” as it were when you accelerate, as the rim of the wheel rotates faster than the tire and the sidewalls during initial acceleration. The resulting twist is called "wrapping". When the tire is wrapped to the maximum, the contact with the track is as long as possible and offers maximum traction. This phenomenon can be seen well in numerous super slow motion videos. As soon as the TF has left the start line, the tires quickly become higher and thus narrower, which leads to less contact with the track surface. At the beginning of this process, a so-called “tire shake” can occur. The reason for this is that the tire does not detach itself from the twist, but rather “rolls over” itself in this state, shaking the car violently.

The tires are made from a very heat-resistant and hard-wearing rubber compound called "D2A". At the center of the tire, this mixture is about 0.20 inches (5.08 mm) thick. That is less than 1% of the total tire structure. The load-bearing structure is a fabric carcass, which consists mainly of nylon and ensures the required flexibility and deformability of the tire. Tire wear is measured through small holes in the rubber, which the team can use to estimate how thick the tread is and when a change is required.

Although “ tire warmers ” would be available for TF dragsters, burn-out has become the main method for increasing the temperature of rear slicks. The dragster drives through a small amount of water and then lets the tires spin, causing them to smoke. During this process, the temperature rises up to 120 ° C. The “high art” in the following is to keep the heat in the tire until the actual start by the driver, with the help of his guide, steer the car back in his own “hot” rubber tracks that he has just laid and additional heat ( and traction) by scrubbing old "rubber compound" off of his tires and adding fresh rubber to the track for extra grip. After a run, the tire temperature can briefly be 160 ° C to 180 ° C, not because of the frictional heat during burn-out , but primarily because of the enormous flexing work (mechanical stress / deformation) of the tire.

Comparison of data

Size comparison of a Hadman Top Fuel Dragster (2005) and a Ferrari F300 (1998)

In order to present the performance values ​​in top fuel drag racing, which are sometimes difficult to believe for the layman, more clearly, comparisons are often made with more familiar processes, devices and situations:

  • Acceleration: The sprint from 0 to 100 mph (160 km / h) is completed in just under 0.8 seconds, after around 200 m, depending on the start and gear ratio, around 450 km / h (280 mph) is reached. The most powerful vehicles of the North American professional series NHRA reach speeds of up to 530 km / h in about 3.8 seconds.
  • Fuel: A TF consumes approx. 5.6 liters of fuel per second under full load. This is roughly the same amount of liquid that a fully loaded Boeing 747 consumes at cruising altitude, or the consumption of 8 bathroom showers running at the same time.
  • Downforce: The exhaust gases escaping from a TF engine under full load produce a contact pressure of around 800-1000 pounds, plus the front and rear wings.
  • Power: A single cylinder of a TF achieves a calculated power of around 940 hp. (As of 2015).
  • Forces: When a TF is started, the driver is affected by around 6G, which roughly corresponds to a space shuttle start. Almost the same forces have a negative effect when braking.
  • Ignition: Each spark plug has the energy output of an arc welder (approx. 55,000 volts or 44 amps). From around half of the distance, the spark plugs burned away and the engine ignites only through the force of the nitro explosions. The only way to stop this is to mechanically cut off the fuel supply.
  • Compressor: The mechanical, belt-driven compressor pushes approx. 180,250 cm³ of air into the combustion chambers at 11,000 rpm. The drive of the supercharger devours more power than an average production V8.
  • Speed: In an average race, a TF motor only makes about 540 revolutions of the crankshaft between start and finish. Together with the burn-out, it comes to about 900 revolutions.
  • Nitro costs: The liter of nitro-methanol costs around 11 euros (as of 2015). Average consumption per run (quarter mile) approx. 38–46 liters. That means approx. 62 liters per kilometer (rounded) = 68,200 euros on (fictitious) 100 kilometers.
  • Costs per run: "If all the equipment has been paid for, the crew works for free and nothing breaks, US professional teams estimate the running second at US $ 2,000." (Quote)
  • Tires: The slicks on the rear axle have a width of 45 cm, a circumference of almost 3 meters and are filled with a pressure of only 0.6 bar. The front wheels are only 6 cm wide and have a pressure of 6.5 bar. All tires must be approved for speeds of up to 563 km / h. US professional teams use a rear tire for 4 to 5 runs (about 2 kilometers). A series production car tire for the EU market has a mileage of around 25,000 to 50,000 km. A TF rear slick costs around US $ 500-600.
  • Brakes: The often mistaken as "parachutes" designated parachutes are used primarily to support and stabilize the 30-cm-carbon brakes, as the high, filled with low air pressure rear tires offer little lateral stability.
  • Pit crew: After each race, the engine of a TF is almost completely dismantled: pistons, connecting rods, clutch are replaced, inspection for any damage, installation of spare parts, reassembly, test run, preparation for the next race (refueling, packing umbrellas). Duration: approx. One and a half hours.

(Source: )

Race distance

After Scott Kalitta's fatal accident in 2008, the NHRA shortened the classic racing distance over the " quartermile " (402.32 meters) for cars in the top fuel category to 1,000 feet (304.80 m). The main objective was to reduce the top speeds, reduce damage to engines and tires, and lengthen the run-off zone. In 2012 the FIA ​​incorporated this distance into the European regulations. For the bikes in the TF category, the regular race distance still applies (as of July 2020)

Records

See: Section Records in Dragster

Drag bikes

Top fuel bike at burn-out before the start
FIM Super Twin Bike on the start line

In the Top Fuel Bike (TF / B) and Super Twin Bike (ST / TF) classes, there are hardly any restrictions on possible modifications. A minimum of 3 cylinders is required for TF bikes. The motors are custom-made, which are usually milled from solid. The main fuel used is nitromethane , but the use of pure methanol and unleaded petrol has recently been permitted. The use of compressors or turbochargers is permitted. When using purely naturally aspirated engines, one or two engines with a maximum displacement of 3278 cm³ are permitted. The maximum permissible displacement for turbocharged 4-cylinder engines is 1700 cm³. Top fuel bikes produce over 1000 hp. Currently (as of 07.2020) the European best times on the quartermile (402.32 m) are 5.662 seconds and 403.6 km / h.

The two-cylinder "STTF" generally come from US American specialist companies and outwardly resemble the V-engines of the traditional Harley-Davidson brand; however, very good results have already been achieved with parallel twins . For naturally aspirated engines , the displacement is limited to 3000 cm³. Charging with compressors or turbochargers is permitted, the maximum permissible displacement is then 2000 cm³ when using 90% nitromethane and 1700 cm³ when using up to 100% nitromethane. The engines deliver over 800 hp and allow quarter mile times of 6.229 seconds and top speeds of 363.88 km / h. (As of 07.2020)

  • FIM / E Top Fuel Bike. Rikard Gustafsson (SWE)

  • FIM / E Super Twin Top Fuel Bike in parallel twin design. Per Bengtson (SWE)

Web links

Individual evidence

  1. ↑ FIA Drag Racing: Technical Regulations and Race Procedures (Section 7)
  2. ^ Robert C. Post: High Performance: The Culture and Technology of Drag Racing, 1950-2000. Revised edition. Johns Hopkins University Press 2001 ISBN 978-0-8018666-4-7 , p. 181
  3. ↑ Phil Burgess: Nostalgia Top Fuelers and Funny Cars will add to 60th Winternationals celebration. In: nhra.com. January 15, 2020, accessed on July 13, 2020 .
  4. ↑ FIA Drag Racing: Technical Regulations and Race Procedures (Section 6 / 4.9)
  5. ↑ Source: Program booklet "NitrOlympX" 2017, starter lists, p. 32
  6. ↑ FIA Drag Racing: Technical Regulations and Race Procedures (Section 6 / 7.4)
  7. ↑ FIA Drag Racing: Technical Regulations and Race Procedures (Section 6 / 9.2)
  8. ↑ FIA Drag Racing: Technical Regulations and Race Procedures (Section 7 / 1.1)
  9. ↑ Heiko Stritzke: 0 to 540 km / h in 3.659 seconds: New dragster record! In: motorsport-total.com. June 11, 2019, accessed July 13, 2020 .
  10. ↑ Markus Stier: Nitrolympx dragster spectacle: Explosive asphalt inferno in Hockenheim. November 2, 2013, accessed July 15, 2020 .
  11. ^ Timmy Calloway: NHRA Top Fuel Dragster fuel pump demo. In: topspeed.com. March 5, 2012, accessed July 15, 2020 .
  12. ↑ https://www.youtube.com/watch?v=mfJejgODr3E Here you can see the difference between the controlled "wrapping" and the uncontrolled "shake" quite clearly.
  13. ↑ a b c Dan Welberry: Top Fuel Dragster / Owner's Workshop Manual . Ed .: Haynes Publishing. Haynes Publishing, Somerset, UK 2014, ISBN 978-0-85733-265-3 , pp. 44-46 .
  14. ↑ a b c Hockenheim-Ring GmbH: Motodrom Insight / The official Hockenheimring magazine . Ed .: Hockenheim-Ring GmbH. Edition 2020. Hockenheim 2020, p. 23 .
  15. ↑ Source: "NitrOlympX" 2015 program, "What you always wanted to know about TF, but ...", pp. 28-29
  16. ↑ FIA: circuit _-_ fia_procedures_for_the_recognition_of_drag_strips _-_ 2016.pdf . Ed .: FIA. No. 7.1. . FIA, S. 3 .
  17. ↑ a b c DR14 FIM EUROPE Technical Rules for Drag Bikes 2020 Point: DR14.4.1 / Engine
  18. ↑ DR14 FIM EUROPE Technical Rules for Drag Bikes 2020 Point: DR14.4.3 / Fuel
  19. ↑ a b Timing data, european bests 2019. In: eurodragster.com. Retrieved July 15, 2020 .