Inlet manifold
In automotive engineering
Automotive engineering
Modern automotive engineering, along with aerospace engineering and marine engineering, is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles,...

, an inlet manifold or intake manifold is the part of an engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

 that supplies the fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

/air mixture to the 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. The word manifold comes from the Old English word manigfeald (from the Anglo-Saxon manig [many] and feald [fold]) and refers to the folding together of multiple inputs and outputs.

In contrast, an exhaust manifold
Exhaust manifold
In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.In contrast, an inlet manifold is the part of an engine...

collects the exhaust gas
Exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline/petrol, diesel fuel, fuel oil or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack or propelling nozzle.It often disperses...

es from multiple cylinders into one pipe.

The primary function of the intake manifold is to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake port in the cylinder head(s). Even distribution is important to optimize the efficiency and performance of the engine. It may also serve as a mount for the carburetor, throttle body, fuel injectors and other components of the engine.

Due to the downward movement of the 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 and the restriction caused by the throttle valve, in a reciprocating spark ignition piston engine, a partial vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...

 (lower than atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

) exists in the intake manifold. This manifold vacuum
Manifold vacuum
Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere....

 can be substantial, and can be used as a source of automobile ancillary power
Automobile ancillary power
]Automobile accessory power can be transferred by several different means. However, it is always ultimately derived from the automobile's internal combustion engine, battery, or other "prime mover" source of energy...

 to drive auxiliary systems: power assisted brake
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....

s, emission control devices, cruise control
Cruise control
Cruise control is a system that automatically controls the speed of a motor vehicle. The system takes over the throttle of the car to maintain a steady speed as set by the driver.-History:...

, ignition
Ignition system
An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol engines used to power the majority of motor vehicles, but they are also used in many other applications such as in oil-fired and...

 advance, windshield wipers, power window
Power window
Power windows or electric windows as well as electric or power window lifts are automobile windows which can be raised and lowered by depressing a button or switch, as opposed to using a hand-turned crank handle.- History :Packard introduced the first power windows in the 1940 Packard...

s, ventilation system valves, etc.

This vacuum can also be used to draw any piston blow-by gases from the engine's 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...

. This is known as a positive crankcase ventilation system. This way the gases are burned with the fuel/air mixture.

The intake manifold has historically been manufactured from aluminum or cast iron but use of composite plastic materials is gaining popularity (e.g. most Chrysler 4 cylinders, Ford Zetec 2.0, Duratec 2.0 and 2.3, and GM's Ecotec
GM Family II engine
The Family II is a straight-4 piston engine that was originally developed by Opel in the early 1970s. It was used in the Opel Ascona and Opel Kadett and their corresponding sister models the Vauxhall Cavalier and Vauxhall Astra...



The carburetor
A carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....

 or the fuel injectors
Fuel injection
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....

 spray fuel droplets into the air in the manifold. Due to electrostatic forces some of the fuel will form into pools along the walls of the manifold, or may converge into larger droplets in the air. Both actions are undesirable because they create inconsistencies in the air-fuel ratio
Air-fuel ratio
Air–fuel ratio is the mass ratio of air to fuel present in an internal combustion engine. If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometric mixture, often abbreviated to stoich...

. Turbulence in the intake causes forces of uneven proportions in varying vectors to be applied to the fuel, aiding in atomization. Better atomization
Atomization or Atomizer may refer to:* The conversion of a vaporized sample into atomic components in atomic spectroscopy* An apparatus using an atomizer nozzle* Atomizer Geyser, a cone geyser in Yellowstone National Park...

 allows for a more complete burn of all the fuel and helps reduce engine knock
Engine knocking
Knocking in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.The...

 by enlarging the flame front. To achieve this turbulence it is a common practice to leave the surfaces of the intake and intake ports in the cylinder head rough and unpolished.

Only a certain degree of turbulence is useful in the intake. Once the fuel is sufficiently atomized additional turbulence causes unneeded pressure drops and a drop in engine performance.

Volumetric efficiency

The design and orientation of the intake manifold is a major factor in the volumetric efficiency
Volumetric efficiency
Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More specifically, volumetric efficiency is a ratio of what quantity of fuel and air actually enters the cylinder during induction to the...

 of an engine. Abrupt contour changes provoke pressure drops, resulting in less air (and/or fuel) entering the combustion chamber; high-performance manifolds have smooth contours and gradual transitions between adjacent segments.

Modern intake manifolds usually employ runners, individual tubes extending to each intake port on the cylinder head which emanate from a central volume or "plenum" beneath the carburetor. The purpose of the runner is to take advantage of the Helmholtz resonance
Helmholtz resonance
Helmholtz resonance is the phenomenon of air resonance in a cavity, such as when one blows across the top of an empty bottle. The name comes from a device created in the 1850s by Hermann von Helmholtz, the "Helmholtz resonator", which he, the author of the classic study of acoustic science, used to...

 property of air. Air flows at considerable speed through the open valve. When the valve closes, the air that has not yet entered the valve still has a lot of momentum and compresses against the valve, creating a pocket of high pressure. This high-pressure air begins to equalize with lower-pressure air in the manifold. Due to the air's inertia, the equalization will tend to oscillate: At first the air in the runner will be at a lower pressure than the manifold. The air in the manifold then tries to equalize back into the runner, and the oscillation repeats. This process occurs at the speed of sound, and in most manifolds travels up and down the runner many times before the valve opens again.

The smaller the cross-sectional area of the runner, the higher the pressure changes on resonance for a given airflow. This aspect of Helmholz resonance reproduces one result of the Venturi effect
Venturi effect
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe. The Venturi effect is named after Giovanni Battista Venturi , an Italian physicist.-Background:...

. When the piston accelerates downwards, the pressure at the output of the intake runner is reduced. This low pressure pulse runs to the input end, where it is converted into an over-pressure pulse. This pulse travels back through the runner and rams air through the valve. The valve then closes.

To harness the full power of the Helmholtz resonance effect, the opening of the intake valve must be timed correctly, otherwise the pulse could have a negative effect. This poses a very difficult problem for engines, since valve timing is dynamic and based on engine speed, whereas the pulse timing is static and dependent on the length of the intake runner and the speed of sound. The traditional solution has been to tune the length of the intake runner for a specific engine speed where maximum performance is desired. However, modern technology has given rise to a number of solutions involving electronically controlled valve timing (for example Valvetronic
The Valvetronic system is a variable valve timing system to offer continuous and precisely variable intake valve lift, from ~0 to 10 mm, and duration. It typically works in conjunction with the independent Double VANOS system that continuously varies the timing...

), and dynamic intake geometry (see below).

As a result of "resonance tuning", some naturally aspirated intake systems operate at a volumetric efficiency above 100%: the air pressure in the combustion chamber before the compression stroke is greater than the atmospheric pressure. In combination with this intake manifold design feature, the exhaust manifold design, as well as the exhaust valve opening time can be so calibrated as to achieve greater evacuation of the cylinder. The exhaust manifolds achieve a vacuum in the cylinder just before the piston reaches top dead center. The opening inlet valve can then—at typical compression ratios—fill 10% of the cylinder before beginning downward travel. Instead of achieving higher pressure in the cylinder, the inlet valve can stay open after the piston reaches bottom dead center while the air still flows in.

In some engines the intake runners are straight for minimal resistance. In most engines, however, the runners have curves...and some very convoluted to achieve desired runner length. These turns allow for a more compact manifold, with denser packaging of the whole engine, as a result. Also, these "snaked" runners are needed for some variable length/ split runner designs, and allow the size of the plenum to be reduced. In an engine with at least six cylinders the averaged intake flow is nearly constant and the plenum volume can be smaller. To avoid standing waves within the plenum it is made as compact as possible. The intake runners each use a smaller part of the plenum surface than the inlet, which supplies air to the plenum, for aerodynamic reasons. Each runner is placed to have nearly the same distance to the main inlet. Runners, whose cylinders fire close after each other, are not placed as neighbors.

"180 degree intake manifolds"....Originally designed for carburetor V8 engines, the two plane, split plenum intake manifold separates the intake pulses which the manifold experiences by 180 degrees in the firing order. This minimizes interference of one cylinder's pressure waves with those of another, giving better torque from smooth mid-range flow. Such manifolds may have been originally designed for either two or four barrel carburetors, but now are used with both throttle-body and multi-point fuel injection. An example of the latter is the Honda J engine
Honda J engine
The J-series was Honda's second V6 engine family, introduced in 1996. It is a 60° V6 – Honda's existing C-series was a 90° engine. The J-series was designed for transverse mounting. It has a shorter bore spacing , shorter connecting rods, and a special smaller crankshaft than the C-series for...

 which converts to a single plane manifold around 3500 rpm for greater peak flow and horsepower.

"Heat Riser" obsolete, earlier manifolds ...with 'wet runners' for carbureted engines...used exhaust gas diversion through the intake manifold to provide vaporizing heat. The amount of exhaust gas flow diversion was controlled by a heat riser valve in the exhaust manifold, and employed a bi-metallic spring which changed tension according to the heat in the manifold. Today's fuel injected engines do not require such devices.

Variable length intake manifold

Variable Length Intake Manifold (VLIM) is an internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 manifold technology.
Four common implementations exist. First, two discrete intake runners with different length are employed, and a butterfly valve can close the short path. Second the intake runners can be bent around a common plenum, and a sliding valve separates them from the plenum with a variable length. Straight high-speed runners can receive plugs, which contain small long runner extensions. The plenum of a 6 or 8 cylinder engine can be parted into halves, with the even firing cylinders in one half and the odd firing cylinders in the other part. Both sub-plenums and the air intake are connected to an Y (sort of main plenum). The air oscillates between both sub-plenums, with a large pressure oscillation there, but a constant pressure at the main plenum. Each runner from a sub plenum to the main plenum can be changed in length. For V engines this can be implemented by parting a single large plenum at high engine speed by means of sliding valves into it when speed is reduced.

As the name implies, VLIM can vary the length of the intake tract in order to optimize power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...

 and torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

, as well as provide better fuel efficiency
Fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...


There are two main effects of variable intake geometry:
  • Venturi effect - At low rpm, the speed of the airflow is increased by directing the air through a path with limited capacity (cross-sectional area). The larger path opens when the load increases so that a greater amount of air can enter the chamber. In dual overhead cam (DOHC) designs, the air paths are often connected to separate intake valves
    Poppet valve
    A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...

     so the shorter path can be excluded by deactivating the intake valve itself.
  • Pressurization - A tuned
    Engine tuning
    Engine tuning is the adjustment, modification or design of internal combustion engines to yield optimal performance, to increase an engine's power output, economy, or durability....

     intake path can have a light pressurizing effect similar to a low-pressure 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,...

     due to Helmholtz resonance. However, this effect occurs only over a narrow engine speed range which is directly influenced by intake length. A variable intake can create two or more pressurized "hot spots." When the intake air speed is higher, the dynamic pressure pushing the air (and/or mixture) inside the engine is increased. The dynamic pressure is proportional to the square of the inlet air speed, so by making the passage narrower or longer the speed/dynamic pressure is increased.

Many automobile manufacturers use similar technology with different names. Another common term for this technology is Variable Resonance Induction System (VRIS).

  • Audi
    Audi AG is a German automobile manufacturer, from supermini to crossover SUVs in various body styles and price ranges that are marketed under the Audi brand , positioned as the premium brand within the Volkswagen Group....

     - 2.8-liter V6 gas engine (1991–98); 3.6 and 4.2 liter V8 engines, 1987–present
  • Alfa Romeo
    Alfa Romeo
    Alfa Romeo Automobiles S.p.A. is an Italian manufacturer of cars. Founded as A.L.F.A. on June 24, 1910, in Milan, the company has been involved in car racing since 1911, and has a reputation for building expensive sports cars...

     - 2.0 TwinSpark 16v - 155 ps(114 kW)
  • 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...

      DISA and DIVA systems
  • Dodge
    Dodge is a United States-based brand of automobiles, minivans, and sport utility vehicles, manufactured and marketed by Chrysler Group LLC in more than 60 different countries and territories worldwide....

     - 2.0 A588 - ECH (2001–2005) used in the 2001-2005 model year Dodge Neon R/T
  • 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...

     - 360 Modena, 550 Maranello
  • Ford
    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...

      VIS (Variable-resonance Intake System) - on their 2.9 liter 24V Cosworth (BOB) based on the Ford Cologne V6 engine
    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...

     in the later model Ford Scorpio
    Ford Scorpio
    The Ford Scorpio is an automobile that was produced by the Ford Motor Company from 1985 through to 1998.It was the replacement for the European Ford Granada line...

  • Ford DSI (Dual-Stage Intake) - on their Duratec 2.5 and 3.0 liter V6s and it was also found on the Yamaha V6 in the Taurus SHO
    Ford Taurus
    The Ford Taurus is an automobile manufactured by the Ford Motor Company in the United States. Originally introduced in the 1986 model year, it has remained in near-continuous production for more than two decades, making it the fourth oldest nameplate that is currently sold in the North American...

  • Ford - The Ford Modular V8 engines
    Ford Modular engine
    The Ford Modular engine is Ford Motor Company's overhead camshaft V8 and V10 engine family, which has been produced in 4.6L, 5.0L , 5.4L, and 6.8L variations. Contrary to popular belief, the Modular engine did not get its name from its design or sharing of certain parts among the engine family...

     sport either the Intake Manifold Runner Control (IMRC) for 4V engines, or the Charge Motion Control Valve (CMCV) for 3V engines.
  • Ford - The 2.0L Split Port engine in the Ford Escort and Mercury Tracer feature an Intake Manifold Runner Control variable geometry intake manifold.
  • 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...

     - 3.9L LZ8/LZ9
    GM High Value engine
    The High Value engine family from General Motors is a group of Cam in Block or "Overhead valve" V6 engines. They use the same 60° vee bank as the 60° V6 family they are based on, but the new bore required offsetting the bores by away from the engine centerline...

     V6, 3.2L LA3
    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....

     V6, and the 4.3L LF4 V6 in some second generation S10s and Sonomas
  • GM Daewoo
    GM Daewoo
    GM Korea Company is South Korea's second largest automobile manufacturer and is a division of the General Motors Company. GM Korea's roots go back to the former Daewoo which was split from its parent company, Daewoo Group, in 2001...

     - DOHC versions of E-TEC II engines
  • Holden
    GM Holden Ltd is an automaker that operates in Australia, based in Port Melbourne, Victoria. The company was founded in 1856 as a saddlery manufacturer. In 1908 it moved into the automotive field, before becoming a subsidiary of the U.S.-based General Motors in 1931...

     - Alloytec
  • 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...

     - Integra
    Honda Integra
    The Honda Integra is a compact luxury performance coupe made by Honda during the years 1985 to 2006. The sporty front wheel drive car is able to house five passengers with a two door hatch or four door sedan available.The Integra was on Car and Driver magazine's annual Ten Best list six times, in...

    , Legend
    Honda Legend
    The Honda Legend is a mid-size luxury car made by the Japanese automaker Honda. It was the result of Project XX, a joint agreement started in November 1981 with the Austin Rover Group of Great Britain and was mechanically related to the Rover 800 series....

    , NSX
    Honda NSX
    The Honda NSX, or Acura NSX, is a sports car that was produced between 1990 and 2005 by the Japanese automaker Honda. It is equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline engine featuring Honda's Variable Valve Timing and Lift Electronic Control ...

    , Prelude
    Honda Prelude
    The Honda Prelude was a sports coupe produced by Japanese automaker Honda from 1978 until 2001. It replaced the Honda S800, a front-engined, front wheel drive sports car...

  • Hyundai
    Hyundai ) is a global conglomerate company, part of the Korean chaebol, that was founded in South Korea by one of the most famous businessmen in Korean history: Chung Ju-yung...

     - XG V6
  • Isuzu
    , is a Japanese car, commercial vehicle and heavy truck manufacturing company, headquartered in Tokyo. In 2005, Isuzu became the world's largest manufacturer of medium to heavy duty trucks. It has assembly and manufacturing plants in the Japanese city of Fujisawa, as well as in the prefectures...

     - Isuzu Rodeo Used in the second generation V6, 3.2L (6VD1) Rodeos.
  • Jaguar
    Jaguar (car)
    Jaguar Cars Ltd, known simply as Jaguar , is a British luxury car manufacturer, headquartered in Whitley, Coventry, England. It is part of the Jaguar Land Rover business, a subsidiary of the Indian company Tata Motors....

     - AJ-V6
    Jaguar AJ-V6 engine
    The Jaguar AJ-V6 engine is a specialized version of Ford's Duratec 25/30 V6. One notable addition is the use of variable valve timing, a feature also shared with Mazda's version of the engine. It is available in 2.0 L, 2.5 L and 3.0 L displacements.Jaguar's AJ-V6 engine has an...

  • 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...

  • Mazda
    is a Japanese automotive manufacturer based in Fuchū, Aki District, Hiroshima Prefecture, Japan.In 2007, Mazda produced almost 1.3 million vehicles for global sales...

      VICS (Variable Inertia Charging System) is used on the Mazda FE-DOHC engine
    Mazda FE-DOHC engine
    The Mazda FE-DOHC was the DOHC variant of the FE. The official Mazda engine codes are FE-DE and FE-ZE, depending on output level. It is still commonly called the FE3 because of its head castings. The FE-DOHC shares the same dimensions as the original FE-SOHC, including the square 86 mm bore ×...

     and Mazda B engine
    Mazda B engine
    The Mazda B-series engine is a small-sized, iron-block, inline four-cylinder with belt-driven SOHC and DOHC valvetrain ranging in displacement from 1.1L to 1.8L. It was used from front-wheel drive economy applications to the turbocharged full-time 4WD 323 GTX and rear-wheel drive Miata as well as...

     family of 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....

    s, and VRIS (Variable Resistance Induction System) in 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...

     family of V6 engines. An updated version of this technology is employed on the new Mazda Z engine
    Mazda Z engine
    The Mazda Z-series is a smaller inline 4-cylinder gasoline engine ranging in displacements from 1.3L to 1.6L. They are the evolution of the cast-iron block B-engine....

    , which is also used by Ford as the Duratec
    Ford Duratec engine
    The Duratec is a range of four, five, and six-cylinder gasoline engines produced by the Ford Motor Company, used in Ford, Mazda, Volvo, Caterham, Morgan, Tiger, Ginetta cars and by specialist engine tuner Cosworth....

  • 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...

  • Mitsubishi
    The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...

      Cyclone is used on the 2.0L I4 4G63 engine family.
  • Nissan I4, V6, V8
  • Opel
    Adam Opel AG, generally shortened to Opel, is a German automobile company founded by Adam Opel in 1862. Opel has been building automobiles since 1899, and became an Aktiengesellschaft in 1929...

     (or Vauxhall) TwinPort - modern versions of Ecotec Family 1 and Ecotec Family 0 straight-4 engines; a similar technology is used in 3.2 L 54° 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....

  • Peugeot
    Peugeot is a major French car brand, part of PSA Peugeot Citroën, the second largest carmaker based in Europe.The family business that precedes the current Peugeot company was founded in 1810, and manufactured coffee mills and bicycles. On 20 November 1858, Emile Peugeot applied for the lion...

     2.2 L I4, 3.0 L V6
  • 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....

     VarioRam - 964
    Porsche 964
    The Porsche 964 is the company's internal name for the version of the Porsche 911 model manufactured and sold between 1989 and 1994. It featured significant styling revisions over previous versions of the 911, most prominently the more integrated bumpers , although it was still obviously a 911...

    , 993
    Porsche 993
    The Porsche 993 is the company's internal name for the version of the Porsche 911 model manufactured and sold between late 1993 and early 1998, replacing the 964...

    , 996
    Porsche 996
    The Porsche 996 is the internal designation for the Porsche 911 model manufactured and sold between 1998 and 2005. It has since been replaced by the Type 997...

    , Boxster
    Porsche Boxster
    The Porsche Boxster is a mid-engined roadster built by Porsche. The Boxster is Porsche's first road vehicle to be originally designed as a roadster since the 550 Spyder....

  • Proton Campro CPS and VIM - Proton Gen-2 CPS
    Proton Gen-2
    Sometime after the launch of the standard Gen-2, comes the special edition. It is fitted with a full body-kit, leather seats and lightweight sport rims. Handling is slightly better with the broader tires fitted and it is more aerodynamic...

     and Proton Waja CPS
    Proton Waja
    The Proton Waja is a saloon car designed in-house by Malaysian automotive company, Proton, first released in August 2000. The Waja is the first Malaysian-designed car. The name Waja, which means "the king", meaning it is the "king" of all of the previous models. The name was chosen partly to...

    ; Proton Campro IAFM - 2008 Proton Saga
    Proton Saga
    - Saga :The Proton Saga was launched in September 1985 by Malaysia's then Prime Minister, Mahathir bin Mohamad. Before the production of Proton Saga, a contest was held to choose the name of the first national car, and the name Saga was chosen from the winner of the contest, Ismail Jaafar, a...

  • 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...

     - Clio 2.0RS
    Renault Clio
    The Renault Clio is a supermini car produced by the French automobile manufacturer Renault. Originally launched in 1990, it is currently in its third generation...

  • Subaru Legacy 1989-1994 JDM EJ20 2.0 liter naturally aspirated DOHC 16 valve flat-4
  • Subaru SVX 1992-1997 EG33 3.3 liter naturally aspirated DOHC 24 valve flat-6
  • Subaru Legacy and Subaru Impreza1999-2001 JDM EJ20 2.0 liter naturally aspirated DOHC 16 valve flat-4
  • Toyota T-VIS
    Toyota Variable Induction System, or T-VIS, is a variable intake system designed by Toyota to improve the low-end performance of multi-valve engines....

    - (Toyota Variable Induction System) used in the early versions of the 3S-GE, 7M-GE, and 4A-GE engines, and ACIS
    Acoustic Control Induction System
    Acoustic Control Induction System, or ACIS, is an implementation of a Variable Length Intake Manifold system designed by Toyota.Simply put, the ACIS system uses a single intake air control valve located in the intake to vary the length of the intake tract in order to optimize power and torque, as...

    - (Acoustic Control Induction System).
  • 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...

     - 1.6 L I4, VR6, W8
    W8 or W-8 may be:* W8, a postcode district in the W postcode area* W8 engine, an eight cylinder piston engine in a W configuration* Cargojet Airways, IATA airline designator* Worms 3D, the eighth game in the Worms series...

  • Volvo
    AB Volvo is a Swedish builder of commercial vehicles, including trucks, buses and construction equipment. Volvo also supplies marine and industrial drive systems, aerospace components and financial services...

     - VVIS (Volvo Variable Induction System) Volvo B52 engine as found on the Volvo 850
    Volvo 850
    The Volvo 850 is a compact executive car produced by Volvo Cars from 1992 to 1997 and designed by Jan Wilsgaard. Available in sedan/saloon and station wagon/estate body styles, the Volvo 850 was notable as the first front-wheel drive vehicle from this Swedish manufacturer to be exported to North...

     and S70/V70
    Volvo S70
    The Volvo S70 is a mid-size luxury car produced by the Swedish automaker Volvo Cars from 1998 to 2000. The S70 was the saloon/sedan, and the similar V70 the estate/station wagon; they both represented mainly new styling and revised suspensions from the 1993 through 1997 Volvo 850...

    vehicles, and their successors. Longer inlet ducts used between 1500 and 4100 rpm at 80% load or higher.
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