Toyota Supra

The Toyota Supra was a sports car produced by Toyota. Production began in 1979. The Supra was built and designed on the legacy of Toyota's former super sports car, the 2000GT. It bore the common chassis code of "A".

Toyota Celica Supra Mk 1 (1979-1981)

Toyota Celica Supra MkI

The first generation Supra was based largely upon the Toyota Celica liftback, but was longer by 5.1 inches (doors and rear section same length as celica but rear panels differ). Most importantly, the Celica's 4-cylinder engine was replaced by an inline 6. Toyota's original plan for the Supra at this time was to make it a competitor to the very popular Datsun (now Nissan) 240Z; it, in some degree, succeded.

The 1979 (1978 Japan market) Mk 1 was originally equipped with a 110 hp (82 kW) single overhead cam inline-6 motor, the 2.6 L 4M-E (MA46 chassis code) (which was the first Toyota engine with electronic fuel injection). [1] In 1981, the Supra received the 2.8 L 5M-E, (MA47 Chassis code) making 116 hp (87 kW) and 145 ft·lbf (197 N·m) of torque. It was also available in Japan with the 2.0 L M-EU engine MA45 chassis code) and possibly the M-TEU turbo.[2]

As with all subsequent versions of the Supra, the Mk 1 was equipped with either 5 speed manual (W50) or 4 speed automatic transmission, and it also came standard with 4-wheel disc brakes, but retained the T series solid rear axle configuration of the celica in the MA45 version and a larger F series (and optional LSD) In the MA46 and MA47

1981 was the last year that a Celica Supra could be purchased equipped with an 8-track stereo. [3]

Toyota Celica Supra Mk 2 (1982-1986)

Toyota Celica Supra Mk2

Though the Celica name was still used, in its second generation the Supra stood more apart from the Celica. The Mk 2, with its all-new design, quickly became a success in the US where it was awarded the Import Car of the Year by Motor Trend. It also made Car and Driver magazine's Ten Best list for 1983 and 1984.

In the US, the engine was changed from the SOHC 2.8 L 5M-E to the DOHC 2.8 L 5M-GE. The MK2 came in 2 flavors: the P-type (Performance type) and the L-type (Luxury type). They were differentiated by the available options, tire/wheel combo, and body trim: the P-type had fiberglass fender flares over the wheel wells, while the L-type had simple smaller flares molded into the metal above the wheel wells. Typically the P-type came with either 4.10:1 or 4.30:1 rear gearing, while the L-type came with 3.727:1 rear gearing. Both were offered with either the W58 manual 5-speed transmission or the A43DL (1982 only)/A43DE (1983-1986.5) 4-speed automatic transmission. The P-type came with 14X7 wheels and 225/60/14 tires, and the L-type came with 14x5.5 wheels and 195/70/14 tires. As a complement to the superb engine, the Celica Supra's suspension was specially designed by Lotus.

Around the world, the Mk 2 came with a variety of other engines. Some models sent to countries (like Sweden, Switzerland and Australia) retained the Mk 1's 5M-E (In Australia, the only petrol available at that time was leaded), while in Japan the MK2 (MA-63) offered the option of the turbocharged SOHC M-TE engine or the 2 litre twin turbo 1G-GTE (GA61). Also in Japan, where the Mk 2 was badged the Celica XX, some came with the 2.0 L 1G-GEU, since taxes were less on lower-displacement engines. Typically, non-US 5M-GE's made around 170 hp (127 kW), while the US-market version made around 145 hp (108 kW), since the exhaust system was more restrictive to comply with emissions requirements. 1984 and 1985 US models had around 165 hp (123 kW) due to 9.2:1 compression vs the former 8.8:1.

1985 was the end of the Mk 2, but delays in the manufacture of the Mk 3 led to leftover 1985 Mk 2s being offered for sale in the first half of 1986. These were just 1985 models with minor cosmetic changes, as well as the addition of the rear-mounted third brakelight on the hatch.

A popular engine replacement for the Mk 2 is the 6M-GEU, which is a 190 hp (142 kW) 3.0 L version of the 5M-GE. This engine was never available in the Mk 2, but was offered in the JDM-only Crown and Chaser models.

Some possible chassis codes are: MA60, MA61, MA63, MA67, GA60, GA61. (After the body code L & R represented Left hand or Right hand Drive i.e., the MA61L is Left hand Drive, whereas the MA61R is Right hand Drive)

Toyota Supra Mk 3 (1986-1992)

Toyota Supra MA70

In the middle of 1986, Toyota was ready to release its next version of the Supra. The bonds between the Celica and the Supra were cut; now they were two completely different kind of models. The Celica changed to front wheel drive (FWD), while the Supra kept its rear wheel drive (RWD). Though the A60 (Mk II) and A70 (MK III) had similar designs, the engine was a more powerful version than the earlier 2.8 L and 3.0 L engine with two versions*: one with a CT-26 turbo (the 7M-GTE) and one without (the 7M-GE). The non-turbo 7M-GE models came standard with the W58 manual transmission, and the 7M-GTE came standard with the R154. Both were available with an optional automatic transmission, the A340E. During the 1989 year, the car received new tail lights, front bumper, badging and side trim amongst other features.

In 1988 the Turbo-A model was introduced, it was a special design aimed at winning the Group-A touring car championships around the world. There were only 500 Turbo-As ever made. The Turbo-A was a special 7M-GTEU with 267 PS (263 hp/196 kW), making it the fastest Japanese road car until the Nissan Skyline R32-GTR was introduced. The Turbo-A model was only produced in black, all featured leather interiors, a front intercooler inlet, were hardtops and only used MAP engine sensors. Other enhancements include higher boost (7.8psi), long lift cams, larger injectors, larger intercooler and a high flowed version of the CT26 turbocharger.

The A70 Supra was also available in two non export models in Japan, the JZA70 with a 2.5L 280 hp (209 kW) twin-turbo 1JZ-GTE , and the GA70 with a 2.0L 210 hp (157 kW) twin-turbo 1G-GTE.

The third-generation Supra represented a great deal of new technology. In 1986, Supras were already equipped with ABS, TEMS (Toyota Electronically Modulated Suspension). By 1990, airbags became standard.

The 7M-GE MA70 is capable of propelling itself 0-60 in just over 6 seconds with 6.8 psi of boost.

Some possible chassis codes are: MA70, MA71, JZA70, GA70.

Toyota Supra Mk 4 (1993-1998/2002)

Toyota Supra MkIV

With the fourth generation of the Supra, Toyota took a big leap in the direction of a more super sports car. The new Supra was redesigned from the ground up and featured two completely new engines: naturally aspirated 2JZ-GE 220hp and 210lb-ft of torque, or a twin turbocharged 2JZ-GTE making a whopping 320hp, 315 lb-ft of torque. The turbocharged variant could achieve 0–60 in 4.6 seconds and 1/4 mile in just under 13.1 seconds at over 109 mph. The stock turbos are capable of running around 400bhp with an unrestricted airflow/exhaust system and an aftermarket boost controller (commonly known as a BPU setup).

The MKIV Supra's twin turbos actually operated in sequential mode instead of parrallel mode as the "twin turbo" name usually implies. The way that the sequential mode operated was the first turbo starts spooling at low rpms & as the rpms increased, the second turbo joins in. This helped in reducing turbo lag. Most cars which are advertised as "twin turbo" operate by having the two equally sized turbos constantly running in parrallel; the turbos spool up at the same time. For this generation, the Supra received a new 6-speed Getrag transmission on the Turbo models

MKIV Supras have been modified (larger turbos running 30+ psi of boost and other, undisclosed tweaks) to produce over 1200hp and run the 1/4 mile in 7.9 seconds. The stock engines are astonishingly tough, running 600bhp+ as daily drivers without having to uprate any internal components.

In 1998, Toyota ceased to export the cars from Japan, and they stopped production altogether in 2002 due to a decline in sales. Toyota has hinted at a possible revival of the Supra in 2006/2007 pointing at different directions. There is indication that Toyota will base the future Supra on the next generation Altezza, which will be powered by a Twin-Turbocharged V6 Engine, while other speculate that the future Supra will become the next flagship model for the company, knocking the Toyota Century off the flagship spot.


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There is indication that Toyota will base the future Supra on the next generation Altezza, which will be powered by a Twin-Turbocharged V6 Engine, while other speculate that the future Supra will become the next flagship model for the company, knocking the Toyota Century off the flagship spot. In 1887 the Michelson-Morley experiment, using an interferometer to attempt to detect the change in the speed of light caused by the Earth moving with respect to the aether, was a famous null result, showing that there really was no static, pervasive medium throughout space and through which the Earth moved as though through a wind. Toyota has hinted at a possible revival of the Supra in 2006/2007 pointing at different directions. This evolved into the luminiferous aether of the 19th century, but the idea was known to have significant shortcomings - specifically that if the Earth is moving through a material medium, the medium would have to be both extremely tenuous (because the earth is not being detectably slowed in its orbit), and extremely rigid (because vibrations propagate so fast). In 1998, Toyota ceased to export the cars from Japan, and they stopped production altogether in 2002 due to a decline in sales. In the 17th century, theories of the nature of light had required the idea of an aethereal medium which would be the medium to convey waves of light (Newton relied on this idea to explain refraction and radiated heat). The stock engines are astonishingly tough, running 600bhp+ as daily drivers without having to uprate any internal components. This led to the development of the vacuum tube.

MKIV Supras have been modified (larger turbos running 30+ psi of boost and other, undisclosed tweaks) to produce over 1200hp and run the 1/4 mile in 7.9 seconds. A number of electrical properties become observable at this vacuum level, and this renewed interest in vacuum. For this generation, the Supra received a new 6-speed Getrag transmission on the Turbo models. The study of vacuum then lapsed until 1855 when Heinrich Geissler invented the mercury displacement pump and achieved a record vacuum of about 0.1 Torr. Most cars which are advertised as "twin turbo" operate by having the two equally sized turbos constantly running in parrallel; the turbos spool up at the same time. In 1654, Otto von Guericke conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been evacuated. This helped in reducing turbo lag. Robert Boyle later conducted experiments on the properties of vacuum.

The way that the sequential mode operated was the first turbo starts spooling at low rpms & as the rpms increased, the second turbo joins in. Some people believe that although Torricelli produced the first vacuum, it was Blaise Pascal who recognized it for what it was. The MKIV Supra's twin turbos actually operated in sequential mode instead of parrallel mode as the "twin turbo" name usually implies. Following work by Galileo, Evangelista Torricelli argued in 1643 that there was a vacuum at the top of a mercury barometer. The stock turbos are capable of running around 400bhp with an unrestricted airflow/exhaust system and an aftermarket boost controller (commonly known as a BPU setup). Opposition to the idea of a vacuum existing in nature continued into the Scientific Revolution, with scholars such as Paolo Casati taking an anti-vacuist position. The turbocharged variant could achieve 0–60 in 4.6 seconds and 1/4 mile in just under 13.1 seconds at over 109 mph. This speculation became irrelevant after the Paris condemnations of Bishop Tempier, which required there to be no restrictions on the powers of God, which led to the conclusion that God could create a vacuum if he so wished.

The new Supra was redesigned from the ground up and featured two completely new engines: naturally aspirated 2JZ-GE 220hp and 210lb-ft of torque, or a twin turbocharged 2JZ-GTE making a whopping 320hp, 315 lb-ft of torque. There was much discussion of whether the air moved in quickly enough as the plates were separated, or, following William Burley whether a 'celestial agent' prevented the vacuum arising—that is, whether nature abhorred a vacuum. With the fourth generation of the Supra, Toyota took a big leap in the direction of a more super sports car. Medieval thought experiments into the idea of a vacuum considered whether a vacuum was present, if only for an instant, between two flat plates when they were rapidly separated. Some possible chassis codes are: MA70, MA71, JZA70, GA70. The absence of anything implied the absence of God, and hearkened back to the void prior to the story of creation in the book of Genesis. The 7M-GE MA70 is capable of propelling itself 0-60 in just over 6 seconds with 6.8 psi of boost. In the Middle Ages, the idea of a vacuum was thought to be immoral or even heretical.

By 1990, airbags became standard. Later Greek philosophers thought that a vacuum could exist outside the cosmos, but not inside it. In 1986, Supras were already equipped with ABS, TEMS (Toyota Electronically Modulated Suspension). Similarly, Aristotle considered the creation of a vacuum impossible—nothing could not be something. The third-generation Supra represented a great deal of new technology. He believed that all physical things were instantiations of an abstract Platonic ideal, and could not imagine an "ideal" form of a vacuum. The A70 Supra was also available in two non export models in Japan, the JZA70 with a 2.5L 280 hp (209 kW) twin-turbo 1JZ-GTE , and the GA70 with a 2.0L 210 hp (157 kW) twin-turbo 1G-GTE. Plato found the idea of a vacuum inconceivable.

Other enhancements include higher boost (7.8psi), long lift cams, larger injectors, larger intercooler and a high flowed version of the CT26 turbocharger. Ancient Greek philosophers did not like to admit the existence of a vacuum, asking themselves "how can 'nothing' be something?". The Turbo-A model was only produced in black, all featured leather interiors, a front intercooler inlet, were hardtops and only used MAP engine sensors. Historically, there has been much dispute over whether such a thing as a vacuum can exist. The Turbo-A was a special 7M-GTEU with 267 PS (263 hp/196 kW), making it the fastest Japanese road car until the Nissan Skyline R32-GTR was introduced. String theory is believed to be analogous to quantum field theory but one with a huge number of vacua - with the so-called anthropic landscape. There were only 500 Turbo-As ever made. If the theory is obtained by quantization of a classical theory, each stationary point of the energy in the configuration space gives rise to a single vacuum.

In 1988 the Turbo-A model was introduced, it was a special design aimed at winning the Group-A touring car championships around the world. In free (non-interacting) quantum field theories, this state is analogous to the ground state of a quantum harmonic oscillator. During the 1989 year, the car received new tail lights, front bumper, badging and side trim amongst other features. In quantum field theory and string theory, the term "vacuum" is used to represent the ground state in the Hilbert space, that is, the state with the lowest possible energy. Both were available with an optional automatic transmission, the A340E. The best support for vacuum fluctuations is the Casimir effect. The non-turbo 7M-GE models came standard with the W58 manual transmission, and the 7M-GTE came standard with the R154. Vacuum fluctuations may also be related to the so-called cosmological constant in the theory of gravitation, if indeed this entity were to be observed in nature on a macroscopic scale.

Though the A60 (Mk II) and A70 (MK III) had similar designs, the engine was a more powerful version than the earlier 2.8 L and 3.0 L engine with two versions*: one with a CT-26 turbo (the 7M-GTE) and one without (the 7M-GE). While most agree that this represents a significant part of particle physics, it is a concept that would benefit from a deeper understanding than currently available. The Celica changed to front wheel drive (FWD), while the Supra kept its rear wheel drive (RWD). This is called vacuum fluctuation. The bonds between the Celica and the Supra were cut; now they were two completely different kind of models. The lowest possible energy state is called the zero-point energy and consists of a seething mass of virtual particles that have brief existence. In the middle of 1986, Toyota was ready to release its next version of the Supra. More fundamentally, quantum mechanics predicts that vacuum energy can never be exactly zero.

(After the body code L & R represented Left hand or Right hand Drive i.e., the MA61L is Left hand Drive, whereas the MA61R is Right hand Drive). Even the space between molecules is not a perfect vacuum. Some possible chassis codes are: MA60, MA61, MA63, MA67, GA60, GA61. Each atom exists as a probability function of space, which has a certain non-zero value everywheres in a given volume. This engine was never available in the Mk 2, but was offered in the JDM-only Crown and Chaser models. Another reason that perfect vacuum is impossible is the Heisenberg uncertainty principle which states that no particle can ever have an exact position. A popular engine replacement for the Mk 2 is the 6M-GEU, which is a 190 hp (142 kW) 3.0 L version of the 5M-GE. If this soup of photons is in thermodynamic equilibrium with the walls, it can be said to have a particular temperature, as well as a pressure.

These were just 1985 models with minor cosmetic changes, as well as the addition of the rear-mounted third brakelight on the hatch. One reason is that the walls of a vacuum chamber emit light in the form of black-body radiation: visible light if they are at a temperature of thousands of degrees, infrared light if they are cooler. 1985 was the end of the Mk 2, but delays in the manufacture of the Mk 3 led to leftover 1985 Mk 2s being offered for sale in the first half of 1986. Even an ideal vacuum, thought of as the complete absence of anything, will not in practice remain empty. 1984 and 1985 US models had around 165 hp (123 kW) due to 9.2:1 compression vs the former 8.8:1. 1913, p.720). Typically, non-US 5M-GE's made around 170 hp (127 kW), while the US-market version made around 145 hp (108 kW), since the exhaust system was more restrictive to comply with emissions requirements. (See "Polar Magnetic Phenomena and Terrella Experiments", in The Norwegian Aurora Polaris Expedition 1902-1903 (publ.

Also in Japan, where the Mk 2 was badged the Celica XX, some came with the 2.0 L 1G-GEU, since taxes were less on lower-displacement engines. It does not seem unreasonable therefore to think that the greater part of the material masses in the universe is found, not in the solar systems or nebulae, but in "empty" space. Some models sent to countries (like Sweden, Switzerland and Australia) retained the Mk 1's 5M-E (In Australia, the only petrol available at that time was leaded), while in Japan the MK2 (MA-63) offered the option of the turbocharged SOHC M-TE engine or the 2 litre twin turbo 1G-GTE (GA61). We have assumed that each stellar system in evolutions throws off electric corpuscles into space. Around the world, the Mk 2 came with a variety of other engines. He wrote: "It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. As a complement to the superb engine, the Celica Supra's suspension was specially designed by Lotus. In 1913, Norwegian explorer and physicist Kristian Birkeland may have been the first to predict that space is not only a plasma, but also contains "dark matter".

The P-type came with 14X7 wheels and 225/60/14 tires, and the L-type came with 14x5.5 wheels and 195/70/14 tires. The deep vacuum of space could make it an attractive environment for certain processes, for instance those that require ultraclean surfaces. Both were offered with either the W58 manual 5-speed transmission or the A43DL (1982 only)/A43DE (1983-1986.5) 4-speed automatic transmission. The idea of using this wind with a solar sail has been proposed for interplanetary travel. Typically the P-type came with either 4.10:1 or 4.30:1 rear gearing, while the L-type came with 3.727:1 rear gearing. Spacecraft can be buffeted by solar winds, but planets are too massive to be affected. They were differentiated by the available options, tire/wheel combo, and body trim: the P-type had fiberglass fender flares over the wheel wells, while the L-type had simple smaller flares molded into the metal above the wheel wells. Beyond planetary atmospheres, the pressure from photons and other particles from the sun become significant.

The MK2 came in 2 flavors: the P-type (Performance type) and the L-type (Luxury type). [2]. In the US, the engine was changed from the SOHC 2.8 L 5M-E to the DOHC 2.8 L 5M-GE. Studies have discovered that some satellites retrieved from orbit are coated with a very thin layer of urine and fecal matter evidently released from Russian and US space missions. It also made Car and Driver magazine's Ten Best list for 1983 and 1984. The atmosphere in Low Earth Orbit is increasingly being polluted with man-made debris. The Mk 2, with its all-new design, quickly became a success in the US where it was awarded the Import Car of the Year by Motor Trend. Most Earth satellites operate in this region, and they need to fire their engines every few days to maintain orbit.

Though the Celica name was still used, in its second generation the Supra stood more apart from the Celica. In Low Earth Orbit (about 300 km altitude) the atmospheric density is still sufficient to produce significant drag on satellites. [3]. The density of gas decreases with distance from the object. 1981 was the last year that a Celica Supra could be purchased equipped with an 8-track stereo. Stars, planets and moons keep their atmosphere by gravitational attraction, so atmospheres have no firm boundary. As with all subsequent versions of the Supra, the Mk 1 was equipped with either 5 speed manual (W50) or 4 speed automatic transmission, and it also came standard with 4-wheel disc brakes, but retained the T series solid rear axle configuration of the celica in the MA45 version and a larger F series (and optional LSD) In the MA46 and MA47. Neither these photons nor the neutrinos produce a significant interaction with matter, so stars, planets and spacecraft move freely in this near perfect vacuum of interstellar space.

It was also available in Japan with the 2.0 L M-EU engine MA45 chassis code) and possibly the M-TEU turbo.[2]. The current temperature is about 3 K, being merely 3 degrees above the absolute zero of temperature. [1] In 1981, the Supra received the 2.8 L 5M-E, (MA47 Chassis code) making 116 hp (87 kW) and 145 ft·lbf (197 N·m) of torque. All of the observable universe is also filled with large numbers of photons, the so-called cosmic background radiation, and quite likely a correspondingly large number of neutrinos. The 1979 (1978 Japan market) Mk 1 was originally equipped with a 110 hp (82 kW) single overhead cam inline-6 motor, the 2.6 L 4M-E (MA46 chassis code) (which was the first Toyota engine with electronic fuel injection). A perfect vacuum is an ideal state that cannot practically be obtained in a laboratory, nor even in outer space, where there are a few hydrogen atoms per cubic centimeter at 10−14 Pascal or 10−16 Torr. Toyota's original plan for the Supra at this time was to make it a competitor to the very popular Datsun (now Nissan) 240Z; it, in some degree, succeded. The properties of the vacuum remain largely unknown.

Most importantly, the Celica's 4-cylinder engine was replaced by an inline 6. It is cold and has no friction. The first generation Supra was based largely upon the Toyota Celica liftback, but was longer by 5.1 inches (doors and rear section same length as celica but rear panels differ). Much of outer space has the density and pressure of an almost perfect vacuum. . The lowest pressures currently achievable in laboratory are about 10-13 Pa. It bore the common chassis code of "A". Vessels lined with a highly gas-permeable material such as palladium (which is a high-capacity hydrogen sponge) create special outgassing problems.

The Supra was built and designed on the legacy of Toyota's former super sports car, the 2000GT. Your system may be able to evacuate nitrogen, (the main component of air,) to the desired vacuum, but your chamber could still be full of residual atmospheric hydrogen and helium. Production began in 1979. Smaller molecules can leak in more easily and are more easily absorbed by certain materials, and molecular pumps are less effective at pumping gases with lower molecular weights. The Toyota Supra was a sports car produced by Toyota. The impact of molecular size must be considered. The porosity of the metallic chamber walls may have to be considered, and the grain direction of the metallic flanges should be parallel to the flange face.

Some oils and greases will boil off in extreme vacuums. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the absorptivity of hard metals such as stainless steel or titanium must be considered. In ultra-high vacuum systems, some very odd leakage paths and outgassing sources must be considered. Some systems are cooled well below room temperature by liquid nitrogen to shut down residual outgassing and simultaneously cryopump the system.

Once the bulk of the outgassing materials are boiled off and evacuated, the system may be cooled to lower vapour pressures and minimize residual outgassing during actual operation. If necessary, this outgassing of the system can also be performed at room temperature, but this takes much more time. The system is usually baked, preferably under vacuum, to temporarily raise the vapour pressure of all outgassing materials in the system and boil them off. Ultra-high vacuum systems are usually made of stainless steel with metal-gasketed conflat flanges.

On a larger scale, the principles are the same as in a Cryomodule. Cryopumping incorporates the use of introducing cryogenics and a vacuum system. One such method to create a high vacuum to ultra high vacuum is by the use of cryopumps. Yet more specialized pumps become useful:.

Even higher vacuums are possible, but they generally require custom-built equipment, strict operational procedures, and a fair amount of trial-and-error. With careful design and operation, 1μPa is possible. With these standard precautions, vacuums of 1 mPa are easily achieved with off-the-shelf molecular pumps. As a result, many materials that work well in low vacuums, such as epoxy, will become a problematic source of outgassing when attempting to achieve high vacuums.

All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. The system must be clean and free of organic matter to minimize outgassing. High vacuum systems generally require metal chambers with metal O-ring seals such as Klein flanges or ISO flanges. As with mechanical pumps, the base pressure will be reached when leakage, outgassing, and backstreaming equal the pump speed, but now minimizing leakage and outgassing to a level comparable to backstreaming becomes much more difficult.

Both of these pumps will stall and fail to pump if exhausted directly to atmospheric pressure, so they must be exhausted to a lower grade vacuum created by a mechanical pump. Diffusion pumps blow out molecules with jets of oil, while turbomolecular pumps use high speed fans. Both types of pumps blow out gas molecules that diffuse into the pump. The two main types of molecular pumps are the diffusion pump and the turbomolecular pump.

In high vacuum, however, pressure gradients have little effect on fluid flows, and molecular pumps can attain their full potential. Since there is no seal, a small pressure at the exhaust can easily force flow backstream through the pump; this is called stall. They do this at the expense of the seal between the vacuum and their exhaust. Molecular pumps sweep out a larger area than mechanical pumps, and do so more frequently, making them capable of much higher pumping speeds as measured in volume per time.

This regime is generally called high vacuum.. When the distance between the molecules increases, the molecules interact with the walls of the chamber more often than the other molecules, and molecular pumping becomes more effective than compression pumping. At atmospheric pressure and mild vacuums, molecules interact with each other and push on their neighboring molecules in what is known as viscous flow. Matter flows differently at different pressures based on the laws of fluid dynamics.

Fortunately, once the pressure has dropped below 1 kPa or so, another vacuum pumping technique becomes possible. Better pumping technologies must be used to go beyond this barrier. Adding more pumps in parallel or bigger pumps of the same type can still improve the pump-down speed, but they will not reduce the base pressure below ultimate. In this situation, the vacuum will approach the pump's ultimate pressure - the best vacuum that this type of pump can achieve under ideal conditions.

However, there is a point where backstream leakage through the pump and outgassing of the pump oils become the dominant mass flows into the chamber. If the dominant mass flow into the vacuum system is chamber leakage or outgassing of materials under vacuum, then the vacuum can be improved simply by installing bigger pumps with a higher volume flow rate. The base pressure of a rubber- and plastic-sealed piston pump system is typically 1 to 50 kPa, while a scroll pump might reach 10 Pa and a rotary vane oil pump with a clean and empty metallic chamber can easily achieve 0.1 Pa. Outgassing can be reduced by desiccation prior to vacuum pumping.

When the pump's mass flow drops to the same level as the mass flows into the chamber, the system asymptotically approaches a constant pressure called the base pressure. Evaporation and sublimation into a vacuum is called outgassing, and the most common source is water absorbed by materials in the chamber. Meanwhile, the leakage rates, evaporation rates, and sublimation rates produce a constant mass flow into the system. So although the pumping speed remains constant when measured in litres/second, it drops exponentially when measured in kilograms/second. A mechanical vacuum pump moves the same volume of gas with each cycle, but as the chamber's pressure drops, this volume contains less and less mass.

The pump's cavity is then sealed from the chamber, opened to the atmosphere, and squeezed back to a minute size. Because of the pressure differential, some air from the chamber is pushed into the pump's small cavity. Inside the pump, a mechanism expands a small sealed cavity to create a deep vacuum. This is the principle behind most mechanical vacuum pumps.

By repeatedly closing off a compartment of the vacuum and exhausting it, it is possible to pump air out of a chamber of fixed size in a manner analogous to pumping a milkshake out of a glass. For example, your muscles expand your lungs to create a partial vacuum inside them, and air rushes in to fill the vacuum. The easiest way to create an artificial vacuum is to expand the volume of a container.
.

Astrophysicists prefer to use density to describe these environments, in units of particles per cubic metre. In interplanetary and interstellar space, isotropic gas pressure is insignificant when compared to solar pressure, solar wind, and dynamic pressure. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. When the MFP is greater than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply.

As gas pressure decreases, the mean free path (MFP) of the gas molecules increases. Here, 29.92 inHg means perfect vacuum. Thus a vacuum of 26 inHg is equivalent to a pressure of (29.92 - 26) or 3.92 inHg. This means that the pressure in vacuum, when specified in inches of mercury, is equal to the specified inches of mercury subtracted from 29.92.

For commercial purposes, vacuum is often measured in inches of mercury (inHg). It is often also measured using the barometric scale, or as a percentage of atmospheric pressure in bars or atms. The SI unit of pressure is the pascal (abbreviation Pa), but vacuum is usually measured in millimeters of mercury (mmHg) or Torr, with 1 mmHg or 1 Torr equaling 133.3223684 pascals. Engineers measure the degree of vacuum in units of pressure.

In engineering, a vacuum is any region where the gas pressure is less than atmospheric pressure. The antithesis of a vacuum, which is also an ideal unachievable state, is called a plenum. A complete characterization of the physical state would require further parameters, such as temperature. Physicists use the term partial vacuum to describe real-life non-ideal vacuum.

In modern day usage vacuum is considered to exist in an enclosed space or chamber, when the pressure of gaseous environment is lower than atmospheric pressure (760 Torr or 101 kPa), or has been reduced as much as necessary to prevent the influence of some gas on a process being carried out in that space. A perfect vacuum is an ideal state that cannot practically be obtained in a laboratory, nor even in outer space where there are a few hydrogen atoms per cubic centimeter at 10−14 pascal or 10−16 torr. Vacuum ranges do not have universally agreed definitions and often depend on the size of the vacuum chamber, but a typical distribution is as follows:. .

A perfect vacuum with a gaseous pressure of absolute zero is a philosophical concept with no physical reality; see sections below on Vacuum in Space and The Quantum Mechanical Vacuum. vacua) which means "empty," but space can never be perfectly empty. The root of the word vacuum is the Latin word vacuus (pl.
A vacuum is a volume of space that is empty of matter and radiation, including air, so that gaseous pressure is much less than standard atmospheric pressure.

For other uses, see vacuum cleaner, vacuum exercise and Vacuum (musical group).'. Converting them to solids by electrically combining them with other materials, called ion pumping. Converting the molecules of gas to their solid phase by freezing them, called cryopumping or cryotrapping. light bulb.

vacuum tube. vacuum welding. process purging. ultra-clean inert storage.

adhesive preparation. vacuum deposition as in semiconductor fabrication. thermal insulation as in a thermos. freeze drying.

Interstellar space = approximately 1 fPa (10−17 Torr) [1]. Pressure on the Moon = approximately 1 nPa (10−11 Torr). Cryopumped MBE chamber = 100 nPa to 1 nPa (10−9 Torr to 10−11 Torr). Near earth outer space = approximately 100 µPa (10−6 Torr).

Mechanical vacuum pump = approximately 100 Pa to 100 µPa (1 Torr to 10−6 Torr). Mechanical water-sealed liquid ring vacuum pump = approximately 3.2 kPa (24 Torr). Vacuum cleaner = approximately 80 kPa (600 Torr). Atmospheric pressure = variable, but standardised at 101.325  kPa (760 Torr) or 760 mm of mercury.

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