Page 1: Upgrades
Page 2: DTC's
Page 3: Gauge Install
Page 4: Z32 MAF Upgrade
Page 5: Nissan Engine Spec's
Page 6: Megan RAcing Test Pipe
Page 7: How to Clean your Headlights
Page 8: How To Remove Your Air Resricting Vent Thingys
Page 9: GT4 Pix
Page 10: New Fan Clutch Install
Page 11: Tunning Pros Header
Page 12: Turbo Related Terms
Turbo Terms:
Adiabatic: Of, relating to, or being a reversible thermodynamic process that occurs without gain or loss of heat and without a change in entropy.
Atmospheric pressure: Pressure caused by the weight of the atmosphere. At sea level it has a mean value of one atmosphere but reduces with increasing altitude. 1 atmosphere equals 14.7 psi
A/R (Area to Raduis Ratio): This is a formula used to determine the size of an exhaust housing. Larger numbers designate a higher volume internal passage for exhaust gases to flow through. Larger A/R numbers also determine the rpm range in which a turbocharger will enter into its efficiency range. Higher number A/R's require greater exhasut gas energy/velocity to spin a turbine wheel than smaller sized housings of the same turbine wheel trim. Exhaust housings can have the same turbine wheel trim and many different A/R's.
Blow-Off/By-Pass Valve: A spring loaded valve controlled by a diaphragm to relieve the excess pressure of air built up inside the piping of a turbocharged system when the throttle plate closes or upon deceleration
Boost: The difference in pressure between barometric and intake manifold on a turbocharged system
Compression ratio: Ratio of clearance volumes of a cylinder top and bottom dead center. Turbocharged applications usually run lower compression ratios than naturally aspirated engines. 8.0 to 9.0 is the normal range for gasoline burning engines.
Compressor: That portion of the turbocharger which increases the pressure of the air or air'fuel mixture.
Compressor flow range: That area of the compressor map between the surge line and edge of the lowest efficiency island.
Compressor housing: The housing which encloses the the compressor wheel. Sometimes referred to as a the scroll.
Compressor wheel/impeller: The rotating portion of the compressor.
Compressor pressure ratio: Compressor outlet absolute pressure divided by compressor inlet absolute pressure.
This is normally determined by the following formula:
14.7 psi + (boost pressure of the system) ex. 15psi / divided by 1 atmosphere of pressure 14.7 psi. So for example 14.7 + 15 psi of boost / 14.7 = 2.02 pressure ratio.
Density: Weight of air or charge per cubic foot of volume
Diffuser: The stationary portion of the compressor which increases the static pressure or the air or air/fuel mixture. The diffuser area in a turbocharger is located between the flat section inside a compressor housing and the flat area on the backing plate beginning at the edge of the compressor wheel.
Efficiency: Actual performance of a piece of equipment compared to ideal 100%
Exducer: The gas-exit portion of a radial turbine wheel
Inducer: The gas-entry portion of a centrifugal compressor wheel
Intercooler: A heat exchanger which reduces the temperature of the compressed air before it enters the combustion chamber
Normalize: To turbocharge an engine running at high altitude, but only to regain power lost due to the decrease in air density at altitude.
Pressure, absolute: Pressure measured in a complete vacuum.
Pressure, boost: Intake manifold gauge pressure. 1psi boost = 2 in. Hg boost (approx.)
Pressure, guage: Pressure measured between two places. Usually between ambient and intake manifold.
Pressure, static: Pressure measured in a housing or duct through an hole in a wall parallel to the direction of flow.
Scavenging: Removing combustion products from the combustion chamber.
Surge line: A line on a compressor map representing minimum flow at each pressure ratio.
Turbine: That portion of the turbocharger which converts the energy of the exhaust gases to shaft power
Courtesy of: Turbonetics Inc.
