Dyno Shoptalk Definitions
Air Flow; The air flow is
measured in pounds per hour (mass air flow).
BSFC - Brake Specific Fuel Consumption; BSFC is a calculated value stating the pounds of fuel the engine is burning per horsepower per hour, in other words a measurement of engine efficiency. Lower is better.
Corrected Horsepower and Torque; Brake horsepower and torque are usually corrected to a SAE (Society of Automotive Engineers) standard. The corrected horsepower and torque numbers offer an accurate basis for comparing engine dynamometer tests on different dates, different engines, or in different areas of the world . There are many SAE standards. Correction standard SAE J607 is most commonly used in the racing world. It results in approximately 4% higher corrected hp and torque numbers than SAE J1349. J1349 uses a friction hp number in its correction. The friction hp is tested by "motoring" the test engine on a dyno. Most dynos cannot motor engines and so a standard friction percentage is used. For this reason J607 currently preferred here at RevSearch but we can correct to a few different SAE standards. Ask if you have special requirements.
EGT Avg - Exhaust Gas Temperature Average; This is an average of all the exhaust gas temperatures. The EGTs should be 1350º F - 1400º F in a race engine running on gasoline.
EGT Delta - Exhaust Gas Temperature Delta; This is how much the exhaust gas temperatures vary from one another. Lower is better.
Fuel Flow; The fuel flow is measured in pounds per hour.
Volumetric Efficiency; A four stroke engine's volumetric efficiency would be 100% if it were 360 cubic inches, and it flowed 360 cubic inches of air every two revolutions. With good intake manifold, camshaft, and exhaust header tuning 100%+ VE can be achieved in a naturally aspirated engine. Engines with forced induction will have VEs of well over 100%.
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