I can't expect anyone to learn anything about turbochargers, if they don't understand the language being spoken.
That said, here's a nice glossary *in progress*
A/R: Area/Radius. I'll come back to this later, as I could write a novel on it by itself
Absolute Pressure: Absolute pressure is the total pressure exerted by all elements in the system. This includes atmospheric pressure, vacuum created by the throttle blade, and pressurization due to forced induction.
Atmospheric Pressure: Really before understanding absolute pressure, you need to know about atmospheric pressure. The planet is immersed in an ocean of gas. The atmosphere has weight - approximately 14.7 psi (pounds per square inch) @ sea level. As you move to higher elevations, the pressure lessens. Anyone that lives up in the mountains can attest to it, as the air is thinner. This is also why someone in Denver running 15psi is not running the same pressure that I am here in Florida, running 15psi. I will explain this more in pressure ratio.
Blow Off Valve: A blow off valve's primary purpose is to keep your turbo alive through sudden changes in pressure in the intake tract. A blow off valve generally is used in a MAP based system, as the valve dumps the excess pressure to the atmosphere, which would throw off the readings of a closed metered air flow system.
Boost: The term boost generally refers to any pressurization of the intake tract over that of the atmospheric pressure. The problem people don't see, is that an engine is a glorified air pump. Any pressurization that takes place, is due to restriction in the air pump system. Boost is technically the engine's inability to flow the amount of air being forced into it
Bypass Valve: A bypass valve and a blow off valve have the same functions. The difference is the bypass valve is used in a metered air system, as the excess pressure is bled off from the intact tract, through the bypass valve, and dumped after the air flow meter, and before the turbo. The air has already been metered, and then flows through a circuit back into the turbo again. This keeps the turbo spinning more efficiently than just dumping the excess pressure to the atmosphere. If you want maximum spool between shifts, you want to use a bypass valve. Stock, the 87-92 Toyota Supra does not have a blow off valve. It has a bypass valve, which is also known as a Compressor Bypass Valve (CBV).
CHRA: Center Housing Rotating Assembly. The 'meat' of the turbo, minus the exhaust and compressor housings.
Compressor Inlet: This is the point where the atmospheric air enters the turbocharger.
Compressor Outlet: The is the point where the pressurized air leaves the turbocharger.
Compressor (or Flow) Map: Another I will come back to...
Exducer/Inducer: The inducer is the area of the turbine (or compressor wheel) that the air initially comes in contact with. The exducer is the area of the turbine (or compressor wheel) that the air leaves through. These are what let a turbocharger do its job.
Pressure Measurements: There are many measurements used for pressure. PSI is the most common here in the US of A. 1 Bar = 100kPa (kilopascals - kPa) Atmospheric pressure @ sea level is defined as 101.325 kPa, so atmospheric pressure = 1.01325 bar. 1 bar = 14.5 psi - not 14.7 as commonly thought. Bar is also not the standard of SI pressure, that belongs to N/meter^2 (Newtons per meter squared) as I recall.
Pressure Ratio: The pressure ratio that the turbo sees is defined as the absolute outlet pressure, divided by the absolute inlet pressure. This is taken only at the turbo itself - pressure losses due to the intercooler and piping are seperate from what the turbo itself sees!
Pressurization: Simply increasing the force of air over that of atmospheric force.
Trim: Trim is the inducer squared divided by the exducer squared. It is a ratio, and therefore, a 50 trim T3 and 50 trim T4 wheel are two different beasts!
Turbocharger: A device used to pressurize the intake manifold system of an automotive engine. Energy from the exhaust is used to rotating a turbine sitting in the exhaust, that is connected via a shaft to the compressor sitting in the intake's air flow. As the exhaust wheel spins, the compressor wheel also spins, force feeding air into the system. The center unit that contains the shaft and wheels is known as the CHRA.
Vacuum: A condition where absolute pressure is lower than the atmospheric pressure.
Wastegate: A device used to control how much energy from the exhaust is fed into the turbocharger. The wastegate's job is to divert some exhaust energy from the turbine wheel. This can be done with an internal wastegate (integrated into the exhaust housing), or external wastegate (non-integrated into the exhaust housing).
If you have any terms you'd like added, just PM me
That said, here's a nice glossary *in progress*
A/R: Area/Radius. I'll come back to this later, as I could write a novel on it by itself
Absolute Pressure: Absolute pressure is the total pressure exerted by all elements in the system. This includes atmospheric pressure, vacuum created by the throttle blade, and pressurization due to forced induction.
Atmospheric Pressure: Really before understanding absolute pressure, you need to know about atmospheric pressure. The planet is immersed in an ocean of gas. The atmosphere has weight - approximately 14.7 psi (pounds per square inch) @ sea level. As you move to higher elevations, the pressure lessens. Anyone that lives up in the mountains can attest to it, as the air is thinner. This is also why someone in Denver running 15psi is not running the same pressure that I am here in Florida, running 15psi. I will explain this more in pressure ratio.
Blow Off Valve: A blow off valve's primary purpose is to keep your turbo alive through sudden changes in pressure in the intake tract. A blow off valve generally is used in a MAP based system, as the valve dumps the excess pressure to the atmosphere, which would throw off the readings of a closed metered air flow system.
Boost: The term boost generally refers to any pressurization of the intake tract over that of the atmospheric pressure. The problem people don't see, is that an engine is a glorified air pump. Any pressurization that takes place, is due to restriction in the air pump system. Boost is technically the engine's inability to flow the amount of air being forced into it
Bypass Valve: A bypass valve and a blow off valve have the same functions. The difference is the bypass valve is used in a metered air system, as the excess pressure is bled off from the intact tract, through the bypass valve, and dumped after the air flow meter, and before the turbo. The air has already been metered, and then flows through a circuit back into the turbo again. This keeps the turbo spinning more efficiently than just dumping the excess pressure to the atmosphere. If you want maximum spool between shifts, you want to use a bypass valve. Stock, the 87-92 Toyota Supra does not have a blow off valve. It has a bypass valve, which is also known as a Compressor Bypass Valve (CBV).
CHRA: Center Housing Rotating Assembly. The 'meat' of the turbo, minus the exhaust and compressor housings.
Compressor Inlet: This is the point where the atmospheric air enters the turbocharger.
Compressor Outlet: The is the point where the pressurized air leaves the turbocharger.
Compressor (or Flow) Map: Another I will come back to...
Exducer/Inducer: The inducer is the area of the turbine (or compressor wheel) that the air initially comes in contact with. The exducer is the area of the turbine (or compressor wheel) that the air leaves through. These are what let a turbocharger do its job.
Pressure Measurements: There are many measurements used for pressure. PSI is the most common here in the US of A. 1 Bar = 100kPa (kilopascals - kPa) Atmospheric pressure @ sea level is defined as 101.325 kPa, so atmospheric pressure = 1.01325 bar. 1 bar = 14.5 psi - not 14.7 as commonly thought. Bar is also not the standard of SI pressure, that belongs to N/meter^2 (Newtons per meter squared) as I recall.
Pressure Ratio: The pressure ratio that the turbo sees is defined as the absolute outlet pressure, divided by the absolute inlet pressure. This is taken only at the turbo itself - pressure losses due to the intercooler and piping are seperate from what the turbo itself sees!
Pressurization: Simply increasing the force of air over that of atmospheric force.
Trim: Trim is the inducer squared divided by the exducer squared. It is a ratio, and therefore, a 50 trim T3 and 50 trim T4 wheel are two different beasts!
Turbocharger: A device used to pressurize the intake manifold system of an automotive engine. Energy from the exhaust is used to rotating a turbine sitting in the exhaust, that is connected via a shaft to the compressor sitting in the intake's air flow. As the exhaust wheel spins, the compressor wheel also spins, force feeding air into the system. The center unit that contains the shaft and wheels is known as the CHRA.
Vacuum: A condition where absolute pressure is lower than the atmospheric pressure.
Wastegate: A device used to control how much energy from the exhaust is fed into the turbocharger. The wastegate's job is to divert some exhaust energy from the turbine wheel. This can be done with an internal wastegate (integrated into the exhaust housing), or external wastegate (non-integrated into the exhaust housing).
If you have any terms you'd like added, just PM me
