Flat-12 engine

A flat-12 is a 12-cylinder internal combustion engine in a flat configuration. Rarer, wider, and less tall than a V12, the flat-12 design was used in Formula One and endurance racing and some exotic sports cars.

Flat-12 engines are generally not horizontally opposed engines (boxers), but rather 180° V-engines. A true boxer has one crankpin journal per piston, while in the 180° V-engine, two opposing pistons share the same crankpin journal. The engine also has a naturally lower center of gravity than a V12, but, with the exception of the Mercedes-Benz C291, is mounted somewhat higher in the engine bay to provide clearance for the exhaust system.

Ferrari Testarossa Motor
Ferrari Testarossa flat-twelve engine, mid-mounted

Racing cars

Porsche 360 / Cisitalia Grand Prix

Ferdinand Porsche can be credited for creating the first flat-12 engined car, the supercharged Porsche 360 / Cisitalia Grand Prix, near Gmünd in 1947 but the car never raced.[1]


In 1964-65, Ferrari introduced a flat-12 in the Ferrari 1512 F1 car [2] and won the F1 world championship with a flat-12 layout in the mid- and late 1970s with the Ferrari 312T.[3][4] However, when wing-cars requiring air-flow venturis came along in the late 1970s, the wide flat shape obstructed the airflow and was considered obsolete. A 4.4-5.0 L 180° flat-12 was also introduced by Ferrari in some of their production models, including the Berlinetta Boxer and Testarossa.

Alfa Romeo

The success of the flat-12 design had an influence on Italian manufacturers, including Alfa Romeo. They were unsuccessful with their return to Formula 1 with the flat-12 powered 177, but succeeded in endurance racing with the 33TT12 and 33SC12.

Porsche 917

The Porsche 917 endurance racing car (introduced in 1969, for the sport category) was powered by an air-cooled flat-12. This was an evolution of the Porsche flat-8 boxer engine and used identical cylinders to those found on the 908, but differed in that it used a V12 type crankshaft. The domination of the Porsche 917 over the V12-powered Ferrari 512 probably influenced Ferrari, because they returned to the flat-12 in three-litre water-cooled form for their prototypes and Formula One cars.

Motori Moderni

Motori Moderni designed a 3.5-litre flat-12 engine for Subaru, the 1235, which would be used in the 1990 Coloni Formula One car. The Coloni−Subaru was not competitive and did not start a Grand Prix. The Motori Moderni flat-12 engine also appeared in detuned form in the Jiotto Caspita supercar. This only appeared in a single prototype and was not put into production.

Tecno F1

The Tecno Formula One flat-12 was a failure.


In the early 1990s, Mercedes-Benz built a 3.5-litre M-291 flat-12 engine for endurance racing. This engine employed a cylinder-head design with exhaust ports where the intake ports would normally be (on top of the engine, pointing upwards). The intake ports are between the intake and exhaust camshafts, just above the spark-plugs, pointing at an outward angle from the vertical. Putting the exhaust system on top, rather than underneath, allowed the engine to ride much lower in the engine-bay of the C-291 (and later C-292).

The engine suffered from oil scavenging problems early in development, and although the problem was eventually solved, changes in the rules by the FIA and ACO doomed its prospects.

Military vehicles

Henry Meadows built a flat-12 petrol engine in World War II for the British Covenanter tank.

In 1954, Panhard fitted a flat-12 (based on its earlier air-cooled two-cylinder) in the EBR armored car.[5]


Franklin 12 was a series of air-cooled flat-12 aircraft engines produced by Franklin Engine Company in the 1940s and 1950s.

See also

Ferrari flat-12 engine


  1. ^ https://www.stuttcars.com/about-porsche/museum-gmund/ Retrieved 6 April 2017.
  2. ^ http://www.ultimatecarpage.com/car/139/Ferrari-1512-F1.html Retrieved 6 April 2017.
  3. ^ https://www.formula1.com/en/championship/drivers/hall-of-fame/Niki_Lauda.html Retrieved 6 April 2017.
  4. ^ https://www.formula1.com/en/championship/drivers/hall-of-fame/Jody_Scheckter.html Retrieved 6 April 2017.
  5. ^ Ogorkiewicz, R. M. AFV Weapons Profile 039 Panhard Armoured Cars (Windsor, Berks: Profile Publications).
1979 United States Grand Prix

The 1979 United States Grand Prix was a Formula One motor race held on October 7, 1979 at the Watkins Glen Grand Prix Race Course in Watkins Glen, New York. It was the fifteenth and final race of the 1979 World Championship of F1 Drivers and the 1979 International Cup for F1 Constructors. This event was also referred to as the United States Grand Prix East in order to distinguish it from the United States Grand Prix West held on April 8, 1979 in Long Beach, California.

The 59-lap race took place in wet conditions, and was won by Gilles Villeneuve, driving a Ferrari. René Arnoux finished second in a Renault, with Didier Pironi third in a Tyrrell-Ford. The win, Villeneuve's third of the season, enabled him to secure second place in the Drivers' Championship behind team-mate Jody Scheckter.

This was the final F1 race for the 1969 and 1970 championship runner-up Jacky Ickx and former Brabham driver Hans-Joachim Stuck, as well as the final race for the Wolf team. Villeneuve's win was also to be the last for a car with a flat-12 engine and the three points scored by Elio de Angelis would be the last points scored by the Shadow team.

Alfa Romeo Tipo 33

The Alfa Romeo Tipo 33 was a sports racing prototype raced by the Alfa Romeo factory-backed team between 1967 and 1977. These cars took part for Sport Cars World Championship, Nordic Challenge Cup, Interserie and CanAm series. A small number of road going cars were derived from it in 1967, called Alfa Romeo 33 Stradale.

With the 33TT12 Alfa Romeo won the 1975 World Championship for Makes, and with the 33SC12 the 1977 World Championship for Sports Cars, taking the first place in all eight of the championship races.

Alfa Romeo Tipo 512

The Alfa Romeo Tipo 512 was intended for replacement for Alfa Romeo 158 Voiturette racing car. Designed by Wifredo Ricart as his second car for Alfa Romeo after V16-engined Alfa Romeo Tipo 162. The car was first mid-engined Alfa Romeo model. This racing car has flat 12 engine (technically speaking it is 180 degree V12) using mid-engine layout. With two Roots type superchargers, the engine

could produce up to 225 bhp (168 kW) per litre. The engine had very short stroke compared to other Grands Prix cars at that time, only 54.2 millimetres (2.13 in). The potential of this machine is not so clear, since it is a prototype. The power of the engine measured at the bench was of 335 bhp (250 kW) at 8600 rpm. In the Alfa Romeo museum in Arese, alongside the 512 exposed is the following data:the maximum power (estimated) 500 hp (373 kW) at 11,000 rpm and maximum speed over 350 km/h (217 mph).

The car development was finished in 1940 and stopped during World War II, another chassis was built also but this car never raced.

The Tipo 512 was first tested on September 12, 1940, by Alfa Romeo chief test driver Consalvo Sanesi, despite being very powerful its handling was not good

enough. June 19, 1940 Alfa Romeo's test driver Attilio Marinoni was killed while testing 512 suspension fitted to an Alfetta 158.Alfa Romeo won the Formula 1 World Championship with the Alfetta 158 in 1950, taking the place for which 512 was originally designed.

Only 2 prototypes were created. Both are currently on display at the Alfa Romeo Historical Museum in Arese, Italy.

Alfa Romeo in Formula One

Italian motor manufacturer Alfa Romeo has participated many times in Formula One. It currently participates as Alfa Romeo Racing while being operated by Sauber Motorsport AG. The brand has competed in motor racing as both a constructor and engine supplier sporadically between 1950 and 1987, and later as a commercial partner since 2015. The company's works drivers won the first two World Drivers' Championships in the pre-war Alfetta: Nino Farina in 1950; and Juan Manuel Fangio in 1951. Following these successes Alfa Romeo withdrew from Formula One.

During the 1960s, although the company had no official presence in the top tier of motorsport a number of Formula One teams used independently developed Alfa Romeo engines to power their cars. In the early 1970s, Alfa provided Formula One support for their works driver Andrea de Adamich, supplying adapted versions of their 3-litre V8 engine from the Alfa Romeo Tipo 33/3 sports car to power Adamich's McLaren (1970) and March (1971) entries. None of these engine combinations scored championship points.

In the mid-1970s, Alfa engineer Carlo Chiti designed a flat-12 engine to replace the T33 V8, which achieved some success in taking the 1975 World Sportscar Championship. Bernie Ecclestone, then owner of the Brabham Formula One team, persuaded Alfa Romeo to supply this engine free for the 1976 Formula One season. Although the Brabham-Alfa Romeo's first season was relatively modest, during the 1977 and 1978 World Championships their cars took 14 podium finishes, including two race victories for Niki Lauda.

The company's sporting department, Autodelta, returned as the works team in 1979. This second period as a constructor was less successful than the first. Between the company's return and its withdrawal as a constructor at the end of 1985, Alfa works drivers did not win a race and the team never finished higher than sixth in the World Constructors' Championship. The team's engines were also supplied to Osella from 1983 to 1987, but they scored only two World Championship points during this period.

The Alfa Romeo logo returned to Formula One in 2015, appearing on the Scuderia Ferrari cars. In late 2017, Alfa Romeo announced that they were to become title sponsors for Sauber from 2018, and had entered into a technical and commercial partnership with the team. Alfa Romeo returned to the sport as their own team when Sauber was renamed at the beginning of 2019.

Brabham BT46

The Brabham BT46 is a Formula One racing car designed by Gordon Murray for the Brabham team, owned by Bernie Ecclestone, for the 1978 Formula One season. The car featured several radical design elements, one of which was the use of flat panel heat exchangers on the bodywork of the car to replace conventional water and oil radiators. This concept did not work in practice and was removed before the car's race debut, never to be seen again. The cars, however, powered by a flat-12 Alfa Romeo engine, raced competitively with modified nose-mounted radiators for most of the year, driven by Niki Lauda and John Watson, winning one race in this form and scoring sufficient points for the team to finish third in the constructors championship.

The "B" variant of the car, also known as the "fan car", was introduced at the 1978 Swedish Grand Prix as a counter to the dominant ground-effect Lotus 79. The BT46B generated an immense amount of downforce by means of a fan, claimed to be for increased cooling, but which also extracted air from beneath the car. The car only raced once in this configuration in the Formula One World Championship—when Niki Lauda won the 1978 Swedish Grand Prix at Anderstorp. The concept was withdrawn by Brabham after one race even though the FIA had ruled it could be used for the remainder of that season.

Carlo Chiti

Carlo Chiti (19 December 1924 – 7 July 1994) was an Italian racing car and engine designer best known for his long association with Alfa Romeo's racing department.

Born in Pistoia, Tuscany, Chiti graduated with a degree in aeronautical engineering from the University of Pisa in Italy in 1953. He joined Alfa Romeo in 1952 and designed the Alfa Romeo 3000 CM sports car,. When Alfa Romeo's competition department was closed down in the late 1950s Chiti was invited to join Scuderia Ferrari.

At Ferrari Chiti was involved with the design of the 1958 championship winning car Ferrari 246 F1 together with Vittorio Jano and the Ferrari 156 Sharknose car, with which Phil Hill won the 1961 championship. In 1962 Chiti walked out to join the breakaway ATS Formula One team formed by a number of disaffected ex-Ferrari personnel. The ATS project was not successful and did not last long and in 1963 Chiti re-entered competitive motor racing through a new project, Autodelta.

Autodelta enabled Chiti to rekindle his association with Alfa Romeo, for whom he designed a V8 and then a flat-12 engine for their Alfa Romeo Tipo 33 sportscars. These were eventually successful, winning the 1975 World Championship for Makes and 1977 World Championship for Sports Cars. At this time, Chiti became involved in Formula One again, through the Brabham team, who signed an agreement with Alfa Romeo to use Chiti's engines. There was some success – Niki Lauda won two races in a Brabham BT46 with the Alfa engine in the 1978 Formula One season. Brabham designer Gordon Murray persuaded Chiti to produce a V12 engine to allow ground effect to be exploited by the team. However, during the 1979 Formula One season, Brabham's owner Bernie Ecclestone announced that the team would switch to Ford for the next season, prompting Chiti to seek permission from Alfa Romeo to start developing a Formula One car on their behalf. The partnership with Brabham finished before the end of the season.

The Alfa Formula One project started with some promise but was never truly successful. The team achieved two pole positions, with Bruno Giacomelli leading much of the 1980 United States Grand Prix before retiring with electrical trouble. Tragedy also occurred when Patrick Depailler was killed testing for the 1980 German Grand Prix at the Hockenheimring. The team's best season was 1983, when Chiti designed a turbocharged 890T V8 engine, and Alfa Romeo achieved 6th place in the constructors' championship, largely thanks to two second-place finishes for Andrea de Cesaris.

In 1984 Chiti left Alfa Romeo to set up another company, Motori Moderni which concentrated on producing engines for Formula One. Initially the company produced a V6 turbo design, used briefly by the small Italian Minardi team. When the banning of turbos from Formula One was announced, Chiti designed a new 3.5 litre atmospheric flat-12 engine. This was eventually taken up by Subaru, who badged it for use in their brief and completely unsuccessful entry into Formula One with the tiny Coloni team in the 1990 Formula One season.

Carlo Chiti died in 1994 in Milan.

In 1999, Koenigsegg bought blueprints, machining tools and the patent for an unused 4 litre Chiti designed Formula One flat-12 engine.

Coloni C3

The Coloni C3 (also known as the Coloni FC189) was a Formula One racing car designed by Christian Vanderpleyn for the 1989 Formula One season. Built to replace the Coloni FC188 used in the previous season, the C3 used a 3.5-litre Cosworth DFR V8 engine. Although not ready for the start of the 1989 season, the C3 made its début at the 1989 Canadian Grand Prix in the hands of Roberto Moreno and Pierre-Henri Raphanel. The C3 was not successful and frequently failed to pre-qualify for races during 1989. It was updated to the C3B for the 1990 season, with the Cosworth DFR being replaced by a Subaru 1235 flat-12 engine; however, this engine was large, heavy and underpowered. Bertrand Gachot, Coloni's only driver for 1990, failed to pre-qualify in any of the eight races that he drove the C3B. Following a fallout between Enzo Coloni and Subaru, the C3C was developed, once again using the Cosworth DFR; although Gachot was usually able to pre-qualify this version, he never managed to qualify for a race. In 1991, the C3C was evolved into the C4, but results did not improve and Coloni folded at the end of that season.

Ferrari 212 E Montagna

The Ferrari 212 E Montagna was a one-off spyder sports racing car produced by Ferrari in 1968. The car was built on a Dino 206S chassis and used a unique 2-litre, 48-valve, flat-12 engine, a development of the 1512 1.5-litre Formula One engine. Driven by Peter Schetty, the car dominated the 1969 European Hill Climb Championship, placing first in every race it entered and setting many course records.

Ferrari 312T

The Ferrari 312T was a Ferrari Formula One car design, based on the 312B3 from 1974. In various versions, it was used from 1975 until 1980. It was designed by Mauro Forghieri for the 1975 season and was an uncomplicated and clean design that responded to mechanical upgrades.

The 312T series won 27 races, four Constructors' and three Drivers' Championships, making it the most successful car in the history of F1. It was replaced for the 1981 season by the 126 C, Ferrari's first turbocharged F1 car.

Ferrari 312 P

The Ferrari 312 P was a Group 6 Prototype-Sports Car used for racing in 1969 and 1970. The new 1971 version of the sports prototype came with a flat-12 engine, often referred to as a boxer engine. Many publications added the letter B after the P of its name to indicate its engine type, but this variation was never officially sanctioned by Ferrari which simply called it the 1971 312P.

Ferrari Berlinetta Boxer

The Ferrari Berlinetta Boxer (BB) is an automobile that was produced by Ferrari in Italy between 1973 and 1984. Replacing the front engined Daytona, it was the first in a series of Ferraris to use a mid-mounted flat-12 engine. The Boxer was designed by Leonardo Fioravanti and was the first mid-engined road-car to bear the Ferrari name and the Cavallino Rampante (prancing horse) logo. It was replaced by the Testarossa, which continued to use the Flat-12 engine.

The BB was not officially imported into the United States by the Ferrari company, as Enzo Ferrari believed that emerging environmental and safety regulations and a 55 MPH national speed limit suggested the company's 8 cylinder cars would suffice in the US market. Instead, dealers in the United States contracted with independent third parties that made the necessary EPA and US DOT modifications such as the installation of catalytic converters, and many of them are now in the United States.

Ferrari Mythos

The Ferrari Mythos is a mid-engine, rear wheel drive concept car based on the mechanical underpinnings of the Ferrari Testarossa. Designed by Italian design house Pininfarina and developed by automobile manufacturer Ferrari, its world premiere was at the 1989 Tokyo Motor Show.

Ferrari Pinin

The Ferrari Pinin was a one-off concept car created by Italian-design studio Pininfarina, to celebrate the design studios 50th anniversary. Discussed by Enzo Ferrari as being turned into a production model, the proposal was dropped and the car remains a singular concept model, the first four-door Ferrari ever built.

Ferrari Testarossa

The Ferrari Testarossa (Type F110) is a 12-cylinder mid-engine sports car manufactured by Ferrari, which went into production in 1984 as the successor to the Ferrari Berlinetta Boxer. The Pininfarina-designed car was originally produced from 1984 to 1991, with two model revisions following the end of Testarossa production called the 512 TR and F512 M, which were produced from 1992 to 1996. Including revised variations, almost 10,000 cars in total were produced, making it one of the most mass-produced Ferrari models.The Testarossa is a two-door coupé that premiered at the 1984 Paris Auto Show. All versions of the Testarossa were available with a rear-mounted, five-speed manual transmission. The rear mid-engine design (engine between the axles but behind the cabin) keeps the centre of gravity in the middle of the car, which increases stability and improves the car's cornering ability, and thus results in a standing weight distribution of 40% front: 60% rear. The original Testarossa was re-engineered for the 1992 model year and was introduced as the 512 TR (TR meaning TestaRossa), at the Los Angeles Auto Show, effectively as a completely new car, and an improved weight distribution of 41% front, 59% rear. Another new variant called the F512 M was introduced at the 1994 Paris Auto Show. The car dropped the TR initials and added the M which in Italian stood for modificata, or translated to modified, and was the final version of the Testarossa, which continued its predecessor's weight distribution improvement of 42% front, 58% rear. The F512 M was Ferrari's last mid-engine 12-cylinder car (apart from the flagship F50, Enzo and LaFerrari models), and it featured the company's last flat-12 engine. The Testarossa was replaced in 1996 by the front-engine 550 Maranello grand tourer.

Ferrari flat-12 engine

The Ferrari flat-12 engine family is a series of 180° V12 DOHC petrol engines produced by Ferrari from 1973 to 1996. Introduced with the 365 GT4/BB, this engine shared its construction with the flat-12 race-engines used in the 312B and 312 PB, but its displacement, bore & stroke, rods and pistons were the same as the Tipo 251 60° V12 Colombo engine powering the Daytona it replaced.Design and development of the new engine was overseen by Ferrari engineers Giuliano de Angelis and Angelo Bellei.The engine was the first flat-12 cylinder configuration fitted in a Ferrari road car and had factory type reference F102A. It had two valves per cylinder and twin overhead camshafts per bank, although these were now belt driven, instead of by chain as on earlier Ferrari 12-cylinder engines. It was fitted with two banks of two triple-choke Weber 40IF3C carburettors and an electronic ignition system. The block and cylinder heads were constructed from light alloy and featured wet sump lubrication.

In 1976 Ferrari launched a revised version of the BB, the 512 BB, with a flat-12 engine enlarged to 4943cc. Named F102B, it featured a dry sump lubrication system to help the car scavenge oil.In 1981 the 512 BBi replaced the outgoing model’s four triple-choke carburettors with a Bosch K-Jetronic mechanical fuel injection. The new engine got factory type reference F110A but otherwise it was mechanically identical to its predecessor.With the debut of Testarossa in 1984, the evolution of the flat-12 engine saw it equipped with four valves per cylinder: with 390 PS (287 kW; 385 hp) it was the most powerful engine mounted on a production sports car at the time of its launch. It maintained the same cubic capacity of 4943cc of the 512 BBi model, and had factory type reference number F113A. It was fitted with a Marelli Microplex MED120 electronic ignition system and Bosch K-Jetronic fuel injection. Export versions for United States, Canada and Japan had catalytic converter and KE-Jetronic fuel injection. European versions got those features in 1986 and the revised engine was known as F113B.The 1991 512 TR had an upgraded version of the engine used in the Testarossa, maintaining the same cubic capacity of 4.9 L, and had factory type reference number F113D. Changes were made to the porting, with redesigned inlet plenums and larger valves providing more efficient fuel/air mix ingress, whilst the fuel injection and ignition system were changed to a combined Bosch Motronic M2.7 system.For the 1994 F512M the engine was further upgraded with a lightened crankshaft, titanium alloy connecting rods, new pistons and a stainless steel low backpressure exhaust system.The flat-12 production ceased with the F512M, being replaced by the front-engined 550 Maranello which featured the new 65° V12 F133 engine.

Flat engine

A flat engine is an internal combustion engine with horizontally-opposed cylinders. Typically, the layout has cylinders arranged in two banks on either side of a single crankshaft and is otherwise known as the boxer, or horizontally-opposed engine. The concept was patented in 1896 by engineer Karl Benz, who called it the "contra engine."A boxer engine should not be confused with the opposed-piston engine, in which each cylinder has two pistons but no cylinder head. Also, if a straight engine is canted 90 degrees into the horizontal plane, it may be thought of as a "flat engine". Horizontal inline engines are quite common in industrial applications such as underfloor mounting for buses.

True boxers have each crankpin controlling only one piston/cylinder while the 180° engines, which superficially appear very similar, share crankpins. The 180° engine, which may be thought of as a type of V engine, is quite uncommon as it has all of the disadvantages of a flat engine, and few of the advantages.


Mazdaspeed (マツダスピード, Matsudasupīdo) (often stylized in all-caps as MAZDASPEED) is Mazda's in-house performance division. The company is a grassroots racing team in Japan. Now owned by Mazda Motor Corporation, they build production model vehicles, become involved in motorsports development, and offer performance parts and accessories.

Mulsanne Straight

The Mulsanne Straight (Ligne Droite des Hunaudières in French) is the name used in English for a formerly 6 km (3.7 mi) long straight of the Circuit des 24 Heures around which the 24 Hours of Le Mans auto race takes place. Since 1990, the straight is interrupted by two chicanes, with the last section, that includes a kink and a hump, leading to the sharp corner near the village of Mulsanne.

Porsche 917

The Porsche 917 is a sports prototype race car developed by German manufacturer Porsche. The 917 gave Porsche its first overall wins at the 24 Hours of Le Mans in 1970 and 1971. Powered by the Type 912 flat-12 engine of 4.5, 4.9, or 5 litres, the 917/30 Can-Am variant was capable of a 0-62 mph (100 km/h) time of 2.3 seconds, 0–124 mph (200 km/h) in 5.3 seconds, and a test track top speed of up to 240 mph (390 km/h).In 1971 the car featured in the Steve McQueen film Le Mans. In 2017 the car driven by McQueen in the film was sold at auction for $14m, a record price for a Porsche. For the 40th anniversary of the 917 in 2009 Porsche held a special celebration at the Goodwood Festival of Speed (3–5 July).

Stroke cycles
& number of cylinders


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