V6 engine
Overview
 
A V6 engine is a V engine
V engine
A V engine, or Vee engine is a common configuration for an internal combustion engine. The cylinders and pistons are aligned, in two separate planes or 'banks', so that they appear to be in a "V" when viewed along the axis of the crankshaft...

 with six cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

s mounted on the crankcase
Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...

 in two banks of three cylinders, usually set at either a right angle or an acute angle to each other, with all six piston
Piston
A 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 driving a common crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

. It is the second most common engine configuration in modern cars after the inline four
Straight-4
The inline-four engine or straight-four engine is an internal combustion engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft....

.

The V6 is one of the most compact engine configurations, shorter than the straight 4 and in many designs narrower than the V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

, and is well suited to the popular transverse engine
Transverse engine
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the long axis of the vehicle. Many modern front wheel drive vehicles use this engine mounting configuration...

 front-wheel drive
Front-wheel drive
Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel drive and...

 layout.
Encyclopedia
A V6 engine is a V engine
V engine
A V engine, or Vee engine is a common configuration for an internal combustion engine. The cylinders and pistons are aligned, in two separate planes or 'banks', so that they appear to be in a "V" when viewed along the axis of the crankshaft...

 with six cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

s mounted on the crankcase
Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...

 in two banks of three cylinders, usually set at either a right angle or an acute angle to each other, with all six piston
Piston
A 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 driving a common crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

. It is the second most common engine configuration in modern cars after the inline four
Straight-4
The inline-four engine or straight-four engine is an internal combustion engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft....

.

The V6 is one of the most compact engine configurations, shorter than the straight 4 and in many designs narrower than the V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

, and is well suited to the popular transverse engine
Transverse engine
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the long axis of the vehicle. Many modern front wheel drive vehicles use this engine mounting configuration...

 front-wheel drive
Front-wheel drive
Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel drive and...

 layout. It is becoming more common as the space allowed for engines in modern cars is reduced at the same time as power requirements increase, and has largely replaced the inline-6, which is too long to fit in many modern engine compartments. Although it is more complicated and not as smooth as the inline 6, the V6 is more rigid for a given weight, more compact and less prone to torsional vibrations in the crankshaft for a given displacement. The V6 engine has become widely adopted for medium-sized cars, often as an optional engine where a straight-4 is standard, or as a base engine where a V8 is a higher-cost performance option.

Recent forced induction
Forced induction
Forced induction is the process of compressing air on the intake of an internal combustion engine . A forced induction engine uses a gas compressor to increase the pressure, temperature and density of the air...

 V6 engines have delivered horsepower and torque output comparable to contemporary larger displacement, naturally aspirated  V8 engines, while reducing fuel consumption and emissions, such as the Volkswagen Group
Volkswagen Group
Volkswagen Group is a German multinational automobile manufacturing group. , Volkswagen was ranked as the world’s third largest motor vehicle manufacturer and Europe's largest....

's 3.0 TFSI which is supercharged
Supercharger
A 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,...

 and directly injected
Gasoline direct injection
In internal combustion engines, gasoline direct injection , also known as petrol direct injection or direct petrol injection, is a variant of fuel injection employed in modern two-stroke and four-stroke gasoline engines...

, and Ford Motor Company
Ford Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...

's turbocharged
Turbocharger
A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...

 and directly injected EcoBoost V6, both of which have been compared to Volkswagen's 4.2 V8 engine.

Modern V6 engines commonly range in displacement
Engine displacement
Engine 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...

 from 2.5 to 4.3 l (152.4 to 262.2 cuin), though larger and smaller examples have been produced.

History

Some of the first V6-cars were built in 1905 by Marmon. Marmon was something of a V-Specialist which began with V2-engines, then built V4's and V6's, later V8's and in the 1930s Marmon was one of the few car-makers of the world which ever built a V16 car.

From 1908 to 1913 the Deutz Gasmotoren Fabrik produced benzene electric trainsets (Hybrid) which used a V6 as generator-engine.

Another V6-car was designed in 1918 by Leo Goosen for Buick Chief Engineer Walter L. Marr. Only one prototype Buick V6 car was built in 1918 and was long used by the Marr family.

The first series production V6 was introduced by Lancia
Lancia
Lancia Automobiles S.p.A. is an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia and which became part of the Fiat Group in 1969. The company has a long history of producing distinctive cars and also has a strong rally heritage. Some modern Lancias are seen as presenting a more...

 in 1950 with the Lancia Aurelia
Lancia Aurelia
The Lancia Aurelia is a car that was produced by the Italian manufacturer Lancia. Designed by Vittorio Jano, the Aurelia was launched in 1950 and production lasted until the summer of 1958....

. Other manufacturers took note and soon other V6 engines were in use. In 1959, GM
GMC (General Motors division)
GMC is a manufacturer of trucks, vans, military vehicles, and SUVs marketed in North America and the Middle East by General Motors Company. In January 2007, GMC was GM's second-largest-selling North American vehicle division after Chevrolet, ahead of Pontiac....

 introduced a heavy-duty 305 in³ (5 L
Litér
- External links :*...

) 60° V6 for use in their pickup trucks and Suburbans
Chevrolet Suburban
Chevrolet offered a station wagon body, built on the 1/2 ton truck frame. This model was specifically built for National Guard units and Civilian Conservation Corps units. Much of the body was constructed from wood, and could seat up to eight occupants....

, an engine design that was later enlarged to 478 in³ (7.8 L) for heavy truck and bus use.

1962 saw the introduction of the Buick Special
Buick Special
In 1962, the Special was the first American car to use a V6 engine in volume production; it earned Motor Trends Car of the Year for 1962. This 198 in³ Fireball was engineered down from the 215 and used many of the same design parameters, but was cast in iron. Output was 135 hp at...

, which offered a 90° V6 with uneven firing intervals that shared some parts commonality with a small Buick V8
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

 of the period. Consequently the Buick Special met consumer resistance due to its excessive vibration. In 1983, Nissan produced Japan's first V6 engine with the VG series
Nissan VG engine
The VG engine family consists of V6 piston engines designed and produced by Nissan for several vehicles in the Nissan lineup. The VG series started in 1983 becoming Japan's first mass produced V6 engine. VG engines displace between 2.0 L and 3.3 L and feature an iron block and aluminum...

.

Balance and smoothness

Due to the odd number of cylinders in each bank, V6 designs are inherently unbalanced
Engine balance
Engine balance is the design, construction and tuning of an engine to run smoothly. Improving engine balance reduces vibration and other stresses and can improve the overall performance, efficiency, cost of ownership and reliability of the engine, as well as reducing the stress on other machinery...

, regardless of their V-angle. All straight engine
Straight engine
Usually found in four- and six-cylinder configurations, the straight engine, or inline engine is an internal-combustion engine with all cylinders aligned in one row, with no offset...

s with an odd number of cylinders suffer from primary dynamic imbalance
Engine balance
Engine balance is the design, construction and tuning of an engine to run smoothly. Improving engine balance reduces vibration and other stresses and can improve the overall performance, efficiency, cost of ownership and reliability of the engine, as well as reducing the stress on other machinery...

, which causes an end-to-end rocking motion. Each cylinder bank in a V6 has an odd number of pistons, so the V6 also suffers from the same problem unless steps are taken to mitigate it. In the horizontally opposed flat-6
Flat-6
A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase...

 layout, the rocking motions of the two straight cylinder banks offset each other, while in the inline-6 layout, the two ends of engine are mirror images of each other and compensate every rocking motion. Concentrating on the first order rocking motion, the V6 can be assumed to consist of two separate straight-3 where counterweights on the crankshaft and a counter rotating balancer shaft compensate the first order rocking motion. At mating, the angle between the banks and the angle between the crankshafts can be varied so that the balancer shafts cancel each other 90° V6 (larger counter weights) and the even firing 60° V6 with 60° flying arms (smaller counter weights. The second order rocking motion can be balanced by a single co-rotating balancer shaft.).

A 90° V6 can use almost the same technique that balances an even firing 90° crossplane V8
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

 in primary and secondary order. A flatplane V8
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

 is in primary balance because each 4-cylinder bank is in primary balance. In a crossplane V8, balance is achieved at each cylinder pair, since the primary imbalance of a 90° pair is a special case that can be cancelled with a crankshaft counterweight. Secondary balance is achieved by the staggered arrangement of the crossplane crank. A simple 90° V6 with crankshaft counterweights achieves good balance for similar reasons, although the uneven firing intervals will be perceived as roughness at low RPM, making this an unpopular solution. Therefore, designing a smooth V6 engine is a much more complicated problem than the straight-6, flat-6, and V8 layouts. Although the use of offset crankpins, counterweights, and flying arms has reduced the problem to a minor second-order vibration in modern designs, all V6s can benefit from the addition of auxiliary balance shaft
Balance shaft
In piston engine engineering, a balance shaft is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced...

s to make them completely smooth.

When Lancia
Lancia
Lancia Automobiles S.p.A. is an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia and which became part of the Fiat Group in 1969. The company has a long history of producing distinctive cars and also has a strong rally heritage. Some modern Lancias are seen as presenting a more...

 pioneered the V6 in 1950, they used a 60° angle between the cylinder banks and a six-throw crankshaft to achieve equally spaced firing intervals of 120°. This still has some balance and secondary vibration problems. When Buick designed a 90° V6 based on their 90° V8, they initially used a simpler three-throw crankshaft laid out in the same manner as the V8 with pairs of connecting rods sharing the same crankpin, which resulted in firing intervals alternating between 90° and 150°. This produced a rough-running design which was unacceptable to many customers. Arguably, the roughness is in the exhaust note, rather than noticeable vibration, so the perceived smoothness is rather good at higher RPM. Later, Buick and other manufacturers refined the design by using a split-pin crankshaft which achieved a regular 120° firing interval by staggering adjacent crankpins by 15° in opposite directions to eliminate the uneven firing and make the engine reasonably smooth. Some manufacturers such as Buick in later versions of their V6 and Mercedes Benz have taken the 90° design a step further by adding a balancing shaft to offset the primary vibrations and produce an almost fully balanced engine.

Some designers have reverted to a 60° angle between cylinder banks, which produces a more compact engine, but have used three-throw crankshafts with flying arms between the crankpins of each throw to achieve even 120° angles between firing intervals. This has the additional advantage that the flying arms can be weighted for balancing purposes. This still leaves an unbalanced primary couple, which is offset by counterweights on the crankshaft and flywheel to leave a small secondary couple, which can be absorbed by carefully designed engine mounts.

Six-cylinder designs are also more suitable for larger displacement engines than four-cylinder ones because power strokes of pistons overlap. In a four-cylinder engine, only one piston is on a power stroke at any given time. Each piston comes to a complete stop and reverses direction before the next one starts its power stroke, which results in a gap between power strokes and noticeable vibrations. In a six-cylinder engine (other than odd-firing V6s), the next piston starts its power stroke 60° before the previous one finishes, which results in smoother delivery of power to the flywheel. In addition, because inertial forces are proportional to piston displacement, high-speed six-cylinder engines will suffer less stress and vibration per piston than an equal displacement engine with fewer cylinders.

Comparing engines on the dynamometer
Dynamometer
A dynamometer or "dyno" for short, is a device for measuring force, moment of force , or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed .A dynamometer can also be used to determine...

, a typical even-fire V6 shows instantaneous torque peaks of 150% above mean torque and valleys of 125% below mean torque, with a small amount of negative torque (engine torque reversals) between power strokes. On the other hand, a typical four-cylinder engine shows peaks of nearly 300% above mean torque and valleys of 200% below mean torque, with 100% negative torque being delivered between strokes. In contrast, a V8 engine shows peaks of less than 100% above and valleys of less than 100% below mean torque, and torque never goes negative. The even-fire V6 thus ranks between the four and the V8, but closer to the V8, in smoothness of power delivery. An odd-fire V6, on the other hand, shows highly irregular torque variations of 200% above and 175% below mean torque, which is significantly worse than an even-fire V6, and in addition the power delivery shows large harmonic vibrations that have been known to destroy the dynamometer.

60 degrees

The most efficient cylinder bank angle for a V6 is 60 degrees, minimizing size and vibration. While 60° V6 engines are not as well balanced as inline-6 and flat-6
Flat-6
A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase...

 engines, modern techniques for designing and mounting engines have largely disguised their vibrations. Unlike most other angles, 60-degree V6 engines can be made acceptably smooth without the need for balance shafts. When Lancia
Lancia
Lancia Automobiles S.p.A. is an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia and which became part of the Fiat Group in 1969. The company has a long history of producing distinctive cars and also has a strong rally heritage. Some modern Lancias are seen as presenting a more...

 pioneered the 60° V6 in 1950, a 6-throw crankshaft was used to give equal firing intervals of 120°. However, more modern designs often use a 3-throw crankshaft with what are termed flying arms between the crankpins, which not only give the required 120° separation but also can be used for balancing purposes. Combined with a pair of heavy counterweights on the crankshaft ends, these can eliminate all but a modest secondary imbalance which can easily be damped out by the engine mounts.

This configuration is a good fit in cars which are too big to be powered by four-cylinder engines, but for which compactness and low cost are important. The most common 60° V6s were built by General Motors
General Motors
General 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...

 (the heavy duty commercial models, as well as a design used in many GM front wheel drive cars) and Ford European subsidiaries (Essex V6
Ford Essex V6 engine (UK)
The Ford Essex V6 engine was a 60° V6 engine built between 1966 and 1981 by the Ford Motor Company in the United Kingdom at their engine plant in Dagenham, Essex, which gave the engine its name. It was produced in two main capacities, 2.5 L and 3.0 L, and was fitted to a wide range of...

, Cologne V6
Ford Cologne V6 engine
The original Ford Cologne V6, also known as the 'Ford Taunus V6', is a series of 60° cast iron block V6 engines produced continuously by the Ford Motor Company in Cologne, Germany since 1968...

 and the more recent Duratec V6). Other 60° V6 engines are the Chrysler 3.3 V6 engine, the Nissan VQ engine
Nissan VQ engine
The VQ is a V6 piston engine produced by Nissan with displacements varying from 2.0 L to 4.0 L. It is an aluminum block DOHC 4-valve design with aluminum heads. It is fitted with Nissan's EGI/ECCS sequential multi-point fuel injection system...

, the Mazda K engine
Mazda K engine
The Mazda K-series automobile engine is a short stroke, 60° V6 24-valve with belt-driven DOHC and aluminum-alloy cylinder heads and block. Their displacements range from a tiny 1.8 L to 2.5 L. They all use a 27-degree DOHC valvetrain with directly actuated hydraulic bucket lifters...

, the Alfa Romeo V6 engine
Alfa Romeo V6 engine
Alfa Romeos in-house V6 engine design made its initial début in 1979 in the Alfa 6. Introduced in 2.5 L guise, production engines would eventually range from 2.0 L to 3.2 L displacement. With modifications it is possible to increase engine displacement to...

, many Toyota V6 engines, and later versions of the Mercedes-Benz V6 engine.

90 degrees

90° V6 engines are also produced, usually so they can use the same production-line tooling set up to produce V8
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

 engines (which normally have a 90° V angle). Although it is relatively easy to derive a 90° V6 from an existing V8 design by simply cutting two cylinders off the engine, this tends to make it wider and more vibration-prone than a 60° V6. The design was first used by Buick
Buick
Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...

 when it introduced its 198 CID Fireball V6 as the standard engine in the 1962 Special
Buick Special
In 1962, the Special was the first American car to use a V6 engine in volume production; it earned Motor Trends Car of the Year for 1962. This 198 in³ Fireball was engineered down from the 215 and used many of the same design parameters, but was cast in iron. Output was 135 hp at...

. Other examples include the Maserati
Maserati
Maserati is an Italian luxury car manufacturer established on December 1, 1914, in Bologna. The company's headquarters is now in Modena, and its emblem is a trident. It has been owned by the Italian car giant Fiat S.p.A. since 1993...

 V6 used in the Citroën SM
Citroën SM
The Citroën SM is a high-performance coupé produced by the French manufacturer Citroën from 1970 to 1975. The SM placed third in the 1971 European Car of the Year contest, trailing its stablemate Citroën GS, and won the 1972 Motor Trend Car of the Year award in the U.S. in 1972.-History:In 1961,...

, the PRV
PRV engine
The PRV engine is an automobile petrol V6 engine that was developed jointly by Peugeot, Renault and Volvo Cars – and sold from 1974 to 1998. It was gradually replaced after 1994 by another joint PSA-Renault design, known as the ES engine at PSA and the L engine at Renault.-Corporate history:The...

 V6, Chevrolet
Chevrolet
Chevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...

's 4.3 L Vortec 4300 and Chrysler's 3.9 L (238 in³) Magnum V6 and 3.7 L (226 in³) PowerTech V6. The Buick V6 was notable because it introduced the concept of uneven firing, as a result of using the 90° V8 cylinder angle without adjusting the crankshaft design for the V6 configuration. Rather than firing every 120° of crankshaft rotation, the cylinders would fire alternately at 90° and 150°, resulting in strong harmonic vibrations at certain engine speeds. These engines were often referred to by mechanics as "shakers", due to the tendency of the engine to bounce around at idle speed.

More modern 90° V6 engine designs avoid these vibration problems by using crankshafts with offset split crankpins to make the firing intervals even, and often add balancing shafts to eliminate the other vibration problems. Examples include the later versions of the Buick V6, and earlier versions of the Mercedes-Benz V6. The Mercedes V6, although designed to be built on the same assembly lines as the V8, used split crankpins, a counter-rotating balancing shaft, and careful acoustic design to make it almost as smooth as the inline-6 it replaced. However, in later versions Mercedes changed to a 60° angle, making the engine more compact and allowing elimination of the balancing shaft. Despite the difference in V angles, the Mercedes 60° V6s were built on the same assembly lines as 90° V8s.

120 degrees

120° might be described as the natural angle for a V6 since the cylinders fire every 120° of crankshaft rotation. Unlike the 60° or 90° configuration, it allows pairs of pistons to share crank pin
Crank pin
In a reciprocating engine, the crankpins, also known as crank journals are the journals of the big end bearings, at the ends of the connecting rods opposite to the pistons....

s in a three-throw crankshaft without requiring flying arms or split crankpins to be even-firing. However, unlike the crossplane
Crossplane
The crossplane or cross-plane is a crankshaft design for V8 engines with a 90° angle between the cylinder banks.The crossplane crankshaft has four crankpins, each offset at 90° from the adjacent crankpins...

 crankshaft V8, there is no way to arrange a V6 so that unbalanced forces from the two cylinder banks will completely cancel each other. As a result, the 120° V6 acts like two straight-3
Straight-3
A straight-three engine, also known as inline-three engine, or a triple, is a reciprocating piston internal combustion engine with three cylinders arranged in a straight line or plane, side by side....

s running on the same crankshaft and, like the straight-3, suffers from a primary dynamic imbalance which requires a balance shaft
Balance shaft
In piston engine engineering, a balance shaft is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced...

 to offset.

The 120° layout also produces an engine which is too wide for most automobile engine compartments, so it is more often used in racing cars where the car is designed around the engine rather than vice-versa, and vibration is not as important. By comparison, the 180° flat-6
Flat-6
A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase...

 boxer engine is only moderately wider than the 120° V6, and unlike the V6 is a fully balanced configuration with no vibration problems, so it is more commonly used in aircraft and in sports/luxury cars where space is not a constraint and smoothness is important.

Spanish truck manufacturer Pegaso
Pegaso
Pegaso was a Spanish make of trucks, omnibuses, tractors, armored vehicles, and, for a while, sports cars. The parent company, Enasa, was created in 1946 and based in the old Hispano-Suiza factory, under the direction of the renowned automotive engineer Wifredo Ricart...

 built the first production 120° V6 for the Z-207
Pegaso Z-207
The Pegaso Z-207 was a truck model produced in Spain by Enasa from 1955 to 1959. It featured a splendid V6 engine and a stylishly unforgettable cab...

 mid size truck in 1955. The engine, a 7.5-litre alloy Diesel designed under the direction of engineer Wifredo Ricart
Wifredo Ricart
Wifredo Pelayo Ricart Medina was a Spanish engineer, designer and executive manager in the automotive industry, who spent his professional career in Spain and Italy.- The Barcelona "Happy Twenties" :...

 uses a single balance shaft rotating at the speed of the crankshaft

Ferrari
Ferrari
Ferrari S.p.A. is an Italian sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari in 1929, as Scuderia Ferrari, the company sponsored drivers and manufactured race cars before moving into production of street-legal vehicles as Ferrari S.p.A. in 1947...

 introduced a very successful 120° V6 racing engine in 1961. The Ferrari Dino 156 engine was shorter and lighter than the 65° Ferrari V6 engines that preceded it, and the simplicity and low center of gravity of the engine was an advantage in racing. It won a large number of Formula One
Formula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...

 races between and . However, Enzo Ferrari
Enzo Ferrari
Enzo Anselmo Ferrari Cavaliere di Gran Croce OMRI was an Italian race car driver and entrepreneur, the founder of the Scuderia Ferrari Grand Prix motor racing team, and subsequently of the Ferrari car manufacturer...

 had a personal dislike of the 120° V6 layout, preferring a 65° angle, and after that time it was replaced by other engines.

Bombardier
Bombardier Aerospace
Bombardier Aerospace is a division of Bombardier Inc. and is the third-largest airplane manufacturer in the world. It is headquartered in Dorval, Quebec, Canada.- History :...

 designed 120° V220/V300T V6 engines for use in light aircraft. The ignition sequence was symmetrical, with each cylinder firing 120° after the previous cylinder resulting in smooth power delivery. A balance shaft on the bottom of the engine offset the primary dynamic imbalance. The straight, pin-type crankshaft journals in the 120° V-6 layout allowed a shorter and stiffer crankshaft than competing flat-6 engines, while water cooling resulted in better temperature control than air cooling. These engines could run on automotive gasoline rather than avgas
Avgas
Avgas is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas , which is the everyday gasoline used in cars and some non-commercial light aircraft...

. However, the design was shelved in 2006 and there are no plans for production.

Other angles

Narrower angle V6 engines are very compact but can suffer from severe vibration problems unless very carefully designed. Notable V6 bank angles include:
  • The 10.6° and 15° Volkswagen
    Volkswagen
    Volkswagen is a German automobile manufacturer and is the original and biggest-selling marque of the Volkswagen Group, which now also owns the Audi, Bentley, Bugatti, Lamborghini, SEAT, and Škoda marques and the truck manufacturer Scania.Volkswagen means "people's car" in German, where it is...

     VR6, which is such a narrow angle it can use a single cylinder head and double overhead camshafts for both cylinder banks. With seven main bearings, it is more like a staggered-bank in-line six rather than a normal V6, but is only slightly longer and wider than a straight-4.
  • The 45° Electro-Motive 6-cylinder version of their model 567
    EMD 567
    The EMD 567 is a line of diesel engines built by General Motors' Electro-Motive Division. This engine, which succeeded Winton's 201-A, was used in EMD's locomotives from 1938 until its replacement in 1966 by the EMD 645. It has a bore of , a stroke of and a displacement of 567 in³ per cylinder...

     Diesel locomotive
    Diesel locomotive
    A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...

     engine. This angle is optimum for the more common 16-cylinder
    V16 engine
    A V16 engine is a V engine with 16 cylinders. Engines of this number of cylinders are uncommon in automotive use.A V16 engine is perfectly balanced regardless of the V angle without requiring counter-rotating balancing shafts which are necessary to balance Straight-4 and odd number of cylinder...

     version.
  • The 54° GM/Opel V6
    GM 54-Degree V6 engine
    General Motors' Opel subsidiary in Europe designed a compact V6 engine with an odd 54° vee angle. It was an iron block/aluminum head DOHC design with 4 valves per cylinder. All 54° engines were assembled at Ellesmere Port in England....

    , designed to be narrower than normal for use in small front-wheel drive
    Front-wheel drive
    Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel drive and...

     cars.
  • The 65° Ferrari Dino V6, allowing larger carburetors (for potentially higher power in race tuning) than a 60° angle, while suffering a slight increase in vibrations.
  • The 72° Mercedes-Benz
    Mercedes-Benz
    Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...

     Bluetec
    BlueTec
    BlueTec is Daimler AG's marketing name for engines equipped with advanced NOx reducing technology for vehicle emissions control in diesel-powered vehicles...

     Diesel
    Diesel engine
    A 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...

     V6 utilizes a counter-rotating balance shaft and crankpins offset by 48° to eliminate vibration problems and make the engine even-firing.
  • The 75° Isuzu Rodeo and Isuzu Trooper
    Isuzu Trooper
    The Isuzu Trooper was a mid-size SUV produced by the Japanese automaker Isuzu between 1981 and 2005. It was exported worldwide as the Isuzu Bighorn, Isuzu Trooper, Isuzu Trooper II , Caribe 442, Acura SLX, Chevrolet Trooper, Subaru Bighorn, Honda Horizon, Opel/Vauxhall Monterey, Holden Jackaroo,...

     V6 of 3.2 and 3.5 L in both SOHC and DOHC versions.
  • The 80° Honda RA168-E Formula One
    Formula One
    Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...

     engine in the McLaren MP4/4
    McLaren MP4/4
    The McLaren MP4/4 was a highly successful Formula 1 car that competed in the 1988 Formula One season. It was designed by Gordon Murray, who based the design on his lowline Brabham BT55 car of 1986, and American engineer Steve Nichols. It is one of the most dominant Formula One cars ever built,...

    .

Odd and even firing

Many older V6 engines were based on V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....

 designs, in which a pair of cylinders was cut off the front of V8 without altering the V angle or using a more sophisticated crankshaft to even out the firing interval. Most V8 engines share a common crankpin between opposite cylinders in each bank, and a 90° V8 crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

 has just four pins shared by eight cylinders, with two pistons per crankpin, allowing a cylinder to fire every 90° to achieve smooth operation.

Early 90° V6 engines derived from V8 engines had three shared crankpins arranged at 120° from each other, similar to an inline 3-cylinder
Straight-3
A straight-three engine, also known as inline-three engine, or a triple, is a reciprocating piston internal combustion engine with three cylinders arranged in a straight line or plane, side by side....

. Since the cylinder banks were arranged at 90° to each other, this resulted in a firing pattern with groups of two cylinders separated by 90° of rotation, and groups separated by 150° of rotation, causing a notorious odd-firing behavior, with cylinders firing at alternating 90° and 150° intervals. The uneven firing intervals resulting in rough-running engines with unpleasant harmonic vibrations at certain engine speeds.

An example is the Buick 231 odd-fire, which has a firing order
Firing order
The firing order is the sequence of power delivery of each cylinder in a multi-cylinder reciprocating engine.This is achieved by sparking of the spark plugs in a gasoline engine in the correct order, or by the sequence of fuel injection in a Diesel engine...

 1-6-5-4-3-2. As the crankshaft is rotated through the 720° required for all cylinders to fire, the following events occur on 30° boundaries:
Angle 90° 180° 270° 360° 450° 540° 630°
Odd firing 1 6 5 4 3 2
Even firing 1 4 5 6 3 2


More modern 90° V6 engines avoid this problem by using split crankpins
Crank pin
In a reciprocating engine, the crankpins, also known as crank journals are the journals of the big end bearings, at the ends of the connecting rods opposite to the pistons....

, with adjacent crankpins offset by 15° in opposite directions to achieve an even 120° ignition pattern. Such a 'split' crankpin is weaker than a straight one, but modern metallurgical techniques
Metallurgy
Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...

 can produce a crankshaft that is adequately strong.

In 1977, Buick
Buick
Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...

 introduced the new "split-pin crankshaft" in the 231. Using a crankpin that is 'split' and offset by 30° of rotation resulted in smooth, even firing every 120°. However, in 1978 Chevrolet
Chevrolet
Chevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...

 introduced a 90° 200/229 V6, which had a compromise 'semi-even firing' design using a crankpin that was offset by only 18°. This resulted in cylinders firing at 108° and 132°, which had the advantage of reducing vibrations to a more acceptable level and did not require strengthening the crankshaft. In 1985, Chevrolet's 4.3 (later the Vortec 4300) changed it to a true even-firing V6 with a 30° offset, requiring larger crank journals to make them adequately strong.

In 1986, the similarly designed 90° PRV engine
PRV engine
The PRV engine is an automobile petrol V6 engine that was developed jointly by Peugeot, Renault and Volvo Cars – and sold from 1974 to 1998. It was gradually replaced after 1994 by another joint PSA-Renault design, known as the ES engine at PSA and the L engine at Renault.-Corporate history:The...

 adopted the same 30° crankshaft offset design to even out its firing. In 1988, Buick
Buick
Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...

 introduced a V6 engine that not only had split crankpins, but had a counter-rotating balancing shaft between the cylinder banks to eliminate almost all primary and secondary vibrations, resulting in a very smooth-running engine.

Racing use

The V6 engine was introduced into racing by Lancia
Lancia
Lancia Automobiles S.p.A. is an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia and which became part of the Fiat Group in 1969. The company has a long history of producing distinctive cars and also has a strong rally heritage. Some modern Lancias are seen as presenting a more...

 in the early 1950s. After good results with privately entered Aurelia
Lancia Aurelia
The Lancia Aurelia is a car that was produced by the Italian manufacturer Lancia. Designed by Vittorio Jano, the Aurelia was launched in 1950 and production lasted until the summer of 1958....

 saloons Lancia set a works competition department in 1951. Four B20 Coupes were entered in the '51 Mille Miglia
Mille Miglia
The Mille Miglia was an open-road endurance race which took place in Italy twenty-four times from 1927 to 1957 ....

 and the one driven by Giovanni Bracco
Giovanni Bracco
Giovanni Bracco was an Italian racing car driver,remembered for losing control of his Delage 3000, killing five spectators at the 1947 Italian Grand Prix....

 and Umberto Maglioli
Umberto Maglioli
Umberto Maglioli was a racing driver from Italy. He participated in 10 Formula One World Championship Grands Prix, debuting on 13 September 1953. He achieved 2 podiums, and scored a total of 3.33 championship points...

 caused quite a stir by finishing second overally after the 4.1-litre Ferrari driven by Villoresi and Cassani, a car which had three times more power than the Lancia. After that encouraging start Lancia decided to carry on with the endurance racing program, first with specially prepared Aurelias (called Da Corsa) and then with specially built prototypes. A D24 with a 3102 cc V6 making 230 PS won the 1953 Carrera Panamericana
Carrera Panamericana
The Carrera Panamericana was a border-to-border sports car racing event on open roads in Mexico similar to the Mille Miglia and Targa Florio in Italy. Running for five consecutive years from 1950 to 1954, it was widely held by contemporaries to be the most dangerous race of any type in the world...

 with Juan Manuel Fangio
Juan Manuel Fangio
Juan Manuel Fangio , nicknamed El Chueco or El Maestro , was a racing car driver from Argentina, who dominated the first decade of Formula One racing...

 at the wheel.

After that came the Ferrari
Ferrari
Ferrari S.p.A. is an Italian sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari in 1929, as Scuderia Ferrari, the company sponsored drivers and manufactured race cars before moving into production of street-legal vehicles as Ferrari S.p.A. in 1947...

 Dino V6. Alfredo Ferrari
Alfredo Ferrari
Alfredo Ferrari , nicknamed Alfredino or Dino, was the son of Enzo Ferrari. Enzo decided to name Alfredo after his grandfather...

 (nicknamed Dino), son of Enzo Ferrari
Enzo Ferrari
Enzo Anselmo Ferrari Cavaliere di Gran Croce OMRI was an Italian race car driver and entrepreneur, the founder of the Scuderia Ferrari Grand Prix motor racing team, and subsequently of the Ferrari car manufacturer...

, suggested to him the development of a 1.5 L DOHC V6 engine for Formula Two
Formula Two
Formula Two, abbreviated to F2, is a type of open wheel formula racing. It was replaced by Formula 3000 in 1985, but the FIA announced in 2008 that Formula Two would return for 2009 in the form of the FIA Formula Two Championship...

 at the end of 1955. The Dino V6 underwent several evolutions, including an increased engine displacement
Engine displacement
Engine 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 2417 cc, for use in the Ferrari 246
Ferrari 246 F1
The Ferrari 246 F1 was a Ferrari racing car built for the Formula One World Championship of 1958. The regulations for 1954–1960 limited naturally aspirated engines to 2500 cc and for the 1958 season there was a change from alcohol fuels to AvGas....

 Formula One
Formula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...

 car in 1958.

The use of a wide 120° bank angle is appealing for racing engine designers as it permits a low center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...

. This design is even considered superior to the flat-6
Flat-6
A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase...

 in that it leaves more space under the engine for exhaust pipes; thus the crankshaft can be placed lower in the car. The Ferrari 156 built for new Formula One 1.5 L regulations used a Dino V6 engine with this configuration.

The Dino V6 engine saw a new evolution in 1966 when it was adapted to road use and produced by a Ferrari-Fiat joint-venture for the Fiat Dino and Dino 206 GT (this car was made by Ferrari but sold under the brand Dino). This new version was redesigned by Aurelio Lampredi
Aurelio Lampredi
Aurelio Lampredi was an Italian automobile and aircraft engine designer.Born in Livorno, he began his career at Piaggio, makers of the Vespa scooter, but quickly moved up to larger engines...

 initially as a 65° 2 l (122 cu in) V6 with an aluminum block but was replaced in 1969 by a 2.4 l (146.3 cu in) cast-iron block version (the Dino car was renamed the 246GT).

The Fiat Dino and Dino 246GT were phased out in 1974, but 500 engines among the last built were delivered to Lancia
Lancia
Lancia Automobiles S.p.A. is an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia and which became part of the Fiat Group in 1969. The company has a long history of producing distinctive cars and also has a strong rally heritage. Some modern Lancias are seen as presenting a more...

, who was like Ferrari already under the control of Fiat
Fiat
FIAT, an acronym for Fabbrica Italiana Automobili Torino , is an Italian automobile manufacturer, engine manufacturer, financial, and industrial group based in Turin in the Italian region of Piedmont. Fiat was founded in 1899 by a group of investors including Giovanni Agnelli...

. Lancia used them for the Lancia Stratos
Lancia Stratos
The Lancia Stratos HF, widely and more simply known as Lancia Stratos, is a car made by Italian car manufacturer Lancia. The HF stands for High Fidelity...

 which would become one of the most successful rally
Rallying
Rallying, also known as rally racing, is a form of auto racing that takes place on public or private roads with modified production or specially built road-legal cars...

 cars of the decade.

The Alfa Romeo V6
Alfa Romeo V6 engine
Alfa Romeos in-house V6 engine design made its initial début in 1979 in the Alfa 6. Introduced in 2.5 L guise, production engines would eventually range from 2.0 L to 3.2 L displacement. With modifications it is possible to increase engine displacement to...

 was designed in the 1970s by Giuseppe Busso
Giuseppe Busso
Giuseppe Busso was an Alfa Romeo and Ferrari technical designer.Born in Turin, he graduated as an industrial designer, and In 1937 began working for Fiat in its aviation engine department....

, the first car to use them being the Alfa Romeo 6. The over-square V6, with aluminium alloy block and heads, has seen continuous use in road vehicles, from the Alfetta GTV6 onwards. A notable use of the Bussone Sei (Busso's big Six) V6 was the Alfa Romeo 155 V6 TI. Turbocharged, it had a peak power of 490 PS at 11,900 rpm. The 164 introduced a 3 l (182.9 cu in) V6, a 2.0 V6 turbocharged in 1991 and in 1992, a 3.0 L DOHC 24-valve version. The Alfa 156
Alfa Romeo 156
The Alfa Romeo 156 is a compact executive car introduced by Italian automaker Alfa Romeo at the 1997 Frankfurt Motor Show as the replacement for the Alfa Romeo 155...

 introduced a 2.5 L DOHC 24-valve version in 1997. The engine capacity was later increased to 3.2 l (195.1 cu in), where it found application in the 156 GTA, 147 GTA, 166, GT, GTV and Spider 916. Production was discontinued in 2005.

Another influential V6 design was the Renault
Renault
Renault S.A. is a French automaker producing cars, vans, and in the past, autorail vehicles, trucks, tractors, vans and also buses/coaches. Its alliance with Nissan makes it the world's third largest automaker...

-Gordini
Gordini
Gordini is a French sports car manufacturer. The firm was founded by Amédée Gordini nicknamed "Le Sorcier" .Gordini competed in Formula One from 1950 to 1956....

 CH1 V6, designed by François Castaing
François Castaing
François J. Castaing is a 27-year veteran automotive executive with Renault, American Motors, and Chrysler. He is an engineering graduate from École Nationale Supérieure d'Arts et Métiers in Paris, and worked in Europe for Gordini and Renault before being named Vice President for Product...

 and Jean-Pierre Boudy, and introduced in 1973 in the Alpine
Alpine (car)
Alpine was a French manufacturer of racing and sports cars that used rear-mounted Renault engines.Jean Rédélé , the founder of Alpine, was originally a Dieppe garage proprietor, who began to achieve considerable competition success in one of the few French cars produced just after World War...

-Renault A440. The CH1 was a 90° cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...

 block V6, similar to the mass-produced PRV engine in those two respects but otherwise dissimilar. It has been suggested that marketing purposes made the Renault-Gordini V6 adopt those characteristics of the PRV in the hope of associating the two in the public's mind.

Despite such considerations, this engine won the European 2 L prototype championship in 1974 and several European Formula Two
Formula Two
Formula Two, abbreviated to F2, is a type of open wheel formula racing. It was replaced by Formula 3000 in 1985, but the FIA announced in 2008 that Formula Two would return for 2009 in the form of the FIA Formula Two Championship...

 titles. This engine was further developed in a turbocharged 2 L version that competed in Sports car and finally won the 24 Hours of Le Mans
24 Hours of Le Mans
The 24 Hours of Le Mans is the world's oldest sports car race in endurance racing, held annually since near the town of Le Mans, France. Commonly known as the Grand Prix of Endurance and Efficiency, race teams have to balance speed against the cars' ability to run for 24 hours without sustaining...

 in 1978 with a Renault-Alpine A 442 chassis.

The capacity of this engine was reduced to 1.5 L to power the Formula One Renault RS01. Despite frequent breakdowns that resulted in the nickname of the 'Little Yellow Teapot', the 1.5 L finally saw good results in 1979.

Ferrari followed Renault in the turbo revolution by introducing a turbocharged derivative of the Dino design (a 1.5 L 120° V6) with the Ferrari 126. However, the 120° design was not considered optimum for the wing cars
Ground effect in cars
Ground effect is term applied to a series of aerodynamic effects used in car design, which has been exploited to create downforce, particularly in racing cars. This has been the successor to the earlier dominant aerodynamic theory of streamlining...

 of the era and later engines used V angles of 90° or less.

Both Renault and Ferrari failed in their attempt to win the Drivers' Championship with V6 Turbo engines. The first turbocharged engine to win the championship was the Straight-4
Straight-4
The inline-four engine or straight-four engine is an internal combustion engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft....

 BMW
BMW
Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...

.

They were followed by a new generation of Formula One engines, the most successful of these being the TAG V6 (designed by Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....

) and the Honda
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...

 V6. This new generation of engines were characterized by odd V angles (around 80°). The choice of these angles was mainly driven by aerodynamic consideration. Despite their unbalanced designs these engines were both quickly reliable and competitive; this is generally viewed as a consequence of the quick progress of CAD techniques in that era.

In 1989 Shelby tried to bring back the Can-Am series, using the Chrysler 3.3 L (201 cu in)
Chrysler 3.3 engine
This engine was Chrysler's first 60° V6 engine designed and built in-house for front wheel drive vehicles, and their first V6 not based on a V8. It was designed as a larger, more powerful option to the Mitsubishi 3.0 V6 in the minivans and debuted in 1990....

 V6 (not yet offered to the general public) as the powerplant in a special racing configuration making 255 hp. This was the same year that the Viper concept was showed to the public.

Originally the plan was to produce two versions of this race car, a 255 hp version and a 500 hp model, the 255 hp version being the entry circuit. The cars were designed to be a cheap way for more people to enter auto racing. Since all the cars were identical, the winners were to be the people with the best talent, not the team with the biggest pockets. The engines had Shelby seals on them and could only be repaired by Shelby's shop, ensuring that all the engines are mechanically identical.

Only 100 of these 3.3s were ever built. Of these 100, 76 were put into Shelby Can-Am cars (the only 76 that were ever sold). No significant amount of spare parts were produced, and the unsold engines were used for parts/spares. The Shelby specific parts, such as the upper intake manifold, were never made available to the general public. According to a small article in the USA Today (in 1989), these cars were making 250 hp (stock versions introduced in 1990 produced 150 hp) and hitting 160 mph (257.5 km/h) on the track. The engine itself was not that far from a standard-production 3.3. The Shelby engine is only making about 50 hp more than the newest 3.3 factory engines from Chrysler. The Can-Am engine has a special Shelby Dodge upper intake manifold, a special Shelby Dodge throttle body, and a special version of the Mopar 3.3 PCM (which had this engine redlining at 6800 rpm).

Nissan also has a quite successful history of using V6's for racing in both IMSA and the JGTC. Development of their V6s for sports cars began in the early 1980s with the VG engine
Nissan VG engine
The VG engine family consists of V6 piston engines designed and produced by Nissan for several vehicles in the Nissan lineup. The VG series started in 1983 becoming Japan's first mass produced V6 engine. VG engines displace between 2.0 L and 3.3 L and feature an iron block and aluminum...

 initially used in the Z31 300ZX. The engine began life as a SOHC, turbocharged 3.0L power plant with electronic fuel injection, delivering 230 PS. The VG30ET was later revised into the VG30DETT for the Z32 300ZX in 1989. The VG30DETT sported both an additional turbocharger and an extra pair of camshafts, making the engine a genuine DOHC twin-turbo V6 producing 300 PS. Nissan used both of these engines in its IMSA racing program throughout the 1980s and 1990s each producing well over 800 hp. In the Japan Grand Touring Car Championship, or JGTC, Nissan opted for a turbocharged version of its VQ30 making upwards of 500 hp to compete in the GT500 class.

Motorcycle use

Laverda
Laverda
Laverda was an Italian manufacturer of high performance motorcycles. The motorcycles in their day gained a reputation for being robust and innovative....

 showed a 996 cc V6-engined motorcycle at the 1977 Milan show. The motorcycle was raced in the 1978 Bol d'Or.

Marine use

V6 engines are popular powerplants in medium to large outboard motor
Outboard motor
An outboard motor is a propulsion system for boats, consisting of a self-contained unit that includes engine, gearbox and propeller or jet drive, designed to be affixed to the outside of the transom and are the most common motorized method of propelling small watercraft...

s

External links

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