This article gives an outline of Formula One engines, also called Formula One power units since the hybrid era starting in 2014. Since its inception in 1947, Formula One has used a variety of engine regulations. Formulae limiting engine capacity had been used in Grand Prix racing on a regular basis since after World War I. The engine formulae are divided according to era.
Characteristics Formula One currently uses 1.6 litre four-stroke turbocharged 90 degree V6 double-overhead camshaft (DOHC) reciprocating engines. They were introduced in 2014 and have been developed over the subsequent seasons. Mostly from the 2023 season, specifications on Formula One engines, including the software used to control them and the maximum per-engine price to F1 teams of €15,000,000, were frozen until the end of 2025, when the completely new 2026 spec came into effect.
High revolutions The history of F1 engines has always been a quest for more power, and the enormous power a Formula One engine produces is generated by operating at a very high rotational speed, reaching over 20,000 revolutions per minute (rpm) during the 2004–2005 seasons. This is because an engine, theoretically, produces double the power when operated twice as fast if combustion (thermal) efficiency and energy loss remain the same. High-revving engines won races no matter how much fuel they consumed and how much wasted heat they generated, as long as they produced more power than the competition. However, with the increasing cost of the exotic materials and production methods that enabled the high-speed operation and the realisation that such advancements in technology were unlikely to ever apply to production vehicles (because the resultant product is very inefficient), it was decided to limit the maximum rotational speed (rpm) to 19,000 in 2007. The maximum rpm was further limited to 18,000 in 2009 and to 15,000 for the 2014–2021 seasons.Engine / gearbox Understanding the Sport, Official Formula 1 Website
Still, the high speed operation of F1 engines contrasts with road car engines of a similar size, which typically operate at less than 6,000 rpm.
Long conrods The high-speed rotation created a vibration problem caused by secondary imbalance inherent in piston engines. Tony Rudd found in BRM 1.5L P56 V8 engine (11,000 rpm redline) of 1961–1962 that a long conrod, much longer than required, was key to reducing the secondary vibration, enabling a high revolution. Coventry Climax FWMV Mk.III, using a much longer conrod in the same cylinder block as Mk.II, proved this concept in 1963.
The ratio of stroke to center-to-center conrod length determines the level of secondary imbalance/vibration, which occurs because the average piston speed is higher in the upper half of crank rotation than in the lower half (with engine/cylinder positioned upright) because the piston position at 90° BTDC/ATDC is lower than the stroke mid-point due to conrod tilt angle.
Other teams gradually found the secret of the long conrod, but this concept was not used in mass-produced cars for a long time because it was deemed very inefficient in terms of weight and space utilisation for the lower rev range of production engines. High-revving motorcycle engines, and high-end sports car makers used the concept beginning in the 1980's. The 2.0 litre Volvo B5204 five-cylinder was one of the exceptions, where a long conrod was needed to accommodate its 'Modular' production concept, sharing the same cylinder block with the 2.3L B5234. In October 2005, Daihatsu used a long conrod to the extremely long-stroke 1.5L 3SZ-VE engine introduced with desaxe crankshaft, 4-valves, and variable valve timing.
Valve springs Until the mid-1980s Formula One engines were limited to around 12,000 rpm due to the traditional metal springs used to close the valves. The speed required to close the valves at a higher rpm called for ever stiffer springs, which increased the power required to drive the camshaft to open the valves, to the point where the loss nearly offset the power gain through the increase in rpm. They were replaced by pneumatic valve springs introduced by Renault in 1986, which inherently have a rising rate (progressive rate) that allowed them to have an extremely high spring rate at larger valve strokes without much increasing the driving power requirements at smaller strokes, thus lowering the overall power loss. Since the 1990s, all Formula One engine manufacturers have used pneumatic valve springs with pressurised air.
Piston speed In addition to the use of pneumatic valve springs, a Formula One engine's high rpm output has been made possible due to advances in metallurgy and design, allowing lighter pistons and connecting rods to withstand the accelerations necessary to attain such high speeds. Improved design also allows narrower connecting rod ends and so narrower main bearings. This permits higher rpm with less bearing-damaging heat build-up. For each stroke, the piston goes from a virtual stop to almost twice the mean speed (approximately 40 m/s), then back to zero. This occurs once for each of the four strokes in the cycle: one Intake (down), one Compression (up), one Power (ignition-down), one Exhaust (up). Maximum piston acceleration occurs at top dead center (TDC) and is in the region of 95,000 m/s2, about 9,700 times standard gravity (9,700 G).
To lower the maximum piston/conrod acceleration, Formula One cars use short-stroke, multi-cylinder engines that result in lower average piston speed for a given displacement. The number of cylinders peaked at sixteen with the British Racing Motors V16, Coventry Climax FWMW, and BRM P75. It was limited to twelve in 1972, ten in 2000, eight in 2006 and six in 2014. These regulation changes made higher-speed designs more difficult and less efficient. To operate at high engine speeds under such limits, the stroke must be short to prevent catastrophic failure, usually from the connecting rod, which is under very large stresses. Having a short stroke means a relatively large bore is required to reach a given displacement. This results in less efficient combustion, due mostly to flame-front propagation having to travel the long distance (for a volume) of ever thinner disk (larger diameter with less height) -shaped combustion chamber deviating far away from the ideal sphere shape with the tip of spark plug at its center.
Efficiency Due to the higher speed operation and the tighter restriction on the number of cylinders, efficiency of a naturally aspirated Formula One engine did not improve much since the 1967 Ford Cosworth DFV and the mean effective pressure stayed at around 14 bar (1.4 MPa) for a long time.F1 Engine Power Secrets , Ian Bamsey, June 2000 RACER magazine
From the 2014 season, a new concept of limiting the maximum fuel flow rate was introduced, which limits the power if energy loss and air/fuel ratio are constant. While the bore and stroke figures are now fixed by the rules, this regulation promoted the competition to improve powertrain efficiency. Since fuel rate is limited, the rev limit became meaningless, so it was lifted in 2022. During the 2014–2025 turbo-hybrid era, F1 engines typically revved to about 13,000 rpm, while combustion efficiency rose to about 40 bar BMEP and beyond, using lean and rapid burn techniques enabling λ>1 (average air/fuel ratio much leaner than 14.7:1 by mass) and very high mechanical and effective compression ratios. Compression ratio is a primary determinant of internal-combustion engine efficiency. Current regulation limits mechanical compression ratio to 18:1, but effective compression ratio after turbocharging is not limited. Honda stated the 18:1 ratio was a target far beyond the imagination in 2014, but is "now starting to feel like a real limitation" in 2023. Intake runner-length tuning contributes to raising the effective compression ratio on production vehicles, but Honda says their F1 engines are using the same resonance effect instead to lower the peaks in intake manifold pressure, leaving the work to raise the pressure to the turbocharger. They say this improves anti-knocking properties, enabling a higher boost.
In addition, energy recovery systems from exhaust pressure (MGU-Heat) and engine-brake (MGU-Kinetic) are allowed to further improve efficiency. MGU-H is an electric motor/generator on the common shaft between the exhaust turbine and intake compressor of the turbocharger, while MGU-K is also an electric motor/generator driven by (or driving) crankshaft at a fixed ratio.
Together with improvements in fuel and these energy recovery systems, F1 engines increased power using the same amount of fuel in recent years. For example, Honda RA621H engine of 2021 season generated over more maximum power over RA615H of the 2015 season at the same 100 kg/h fuel flow rate.
With the hugely improved efficiency of the combustion, mechanicals, software and turbocharger, F1 engines are generating much less heat and noise compared to the levels in 2014. Stefano Domenicali said the 2026 regulation will impose intentionally louder exhaust sound to please the fans.
History Formula One engines have come through various regulations, manufacturers, and configurations. Throughout its history, Formula One has been the forefront for technological innovation in engine design. From the early naturally aspirated engines to the introduction of turbocharged units and hybrid powertrains, each era has pushed the boundaries of engineering. The shift towards hybrids and sustainable technologies reflects the sport's commitment to environmental responsibility and technological advancement. It is imperative to understand the distinction among the terms "Grand Prix", "World Championship" and "Formula One" to come to grips with the history.
Car racing in various forms began almost immediately after the invention of the automobile, and many of the first organised car racing events were held in Europe before 1900. In the case of the Pau – Tarbes – Bayonne – Pau (300km) road race held in 1900, there were no class divisions, and no prize on record was given to the winner, René de Knyff driving a Panhard et Levassor (2.1-litre, four-cylinder engine called the 'Phoenix' jointly developed with Gottlieb Daimler in Germany, about 20 hp), who became the commissioner of the CSI later. In 1901, the event was named "Semaine de Pau (Week in Pau)" held at Circuit de Pau-Ville (2.65km), and the prizes awarded to the winners were "Grand Prix de Pau (Grand Prize of Pau)" for the "650 kg or heavier" class, "Grand Prix du Palais d'Hiver (Grand Prize of the Winter Palace)" for "400 – 650 kg" class, and "Second Grand Prix du Palais d'Hiver" for the "under 400 kg" class. This event is significant not only because it called the prizes Grand Prix, but also because it was one of the very first automobile race events, including the fastest class of cars, held on a closed circuit.
It became obvious that the size of the engines (and whether they were supercharged) primarily determined how fast they could run, rather than the size and weight of the cars. After a period with series of fatal accidents and regulation changes, "under 1,500 cc with supercharger, or 4,500 cc without" was applied to the Grand Prix races for Voiture class in France, starting with the 1914 French Grand Prix. The Voiturette class was re-defined as "under 1,100 cc, no supercharger".
After World War I (1914–1918), countries outside of France started using the "Grand Prix" name for races with different regulations, and in 1922, Commission Sportive Internationale (CSI), an international race governing committee was established by Automobile Club of France on behalf of AIACR. This AIACR sanctioned the Automobile World Championship from 1925 to 1930, European Drivers' Championship from 1931 to 1939, and later became the Fédération Internationale de l'Automobile (FIA) in 1946.