Specializing in Dirt Bike, Motorcycle, ATV, & Snowmobile - Service and Repair
What can we do with our
Dynomometer
Power Measurement
What is a Dynomometer
Chassis Dynamometer Tuning Centre for Snowmobiles, Motorcycles and ATV's featuring Dynojet Chassis Dynamometer and Dynojets real-time gas analizer.
DYNOMOMETER TUNING
A dynamometer is a measuring device for recording and displaying power and torque of an engine. Its method of measurement is a direct implementation of the definitions of power and torque. Correction factors assist in the comparison of these measurements under various test conditions, making computer hardware and software necessary to obtain, interpret, and display the data.
Power is coupled to the drum by friction developed between the driving tire of the vehicle and the knurled steel surface of the drum of the dynamometer.The dynamometer measures power according to the terms just described. It measures velocity by measuring the time it takes to rotate a heavy steel drum one turn. The dyno measures force at the surface of the drum by indirectly measuring its acceleration. Acceleration is simly the difference in velocity at the surface of the drum from one revolution to the next.
Tourque Measurement
The Torque on the dyno's drum can be calculated by multiplying the force appled by the drum's radius. However, engine torque is not equal to drum torque because the gearing through the drive train changes the moment arm. The change in the moment arm is proportional to the ratio of engine speed to drum speed. Therefore, tachometer readings are necessary to calculate and display engine torque.
Corection Factors
Correction factors are used to compensate engine horsepower measurements for differences in operation conditions during engine testing. The typical correction factor (CF) is calculated based on the absolute barometric pressure, air temperature and water content of the air used for combustion by the engine under test. It attempts to predict the horsepower that would be developed if the engine were tested at sea level under standard pressure and temperature conditions.
Absolute Barometric Pressure
Absolute barometric pressure is a measure of how hard the air molecules are being pushed closer to one another. The unit of measurement is typically inches of mercury (inches Hg). The more pressure, the more molecules there are in a liter of air and the more air the engine gobbles up during the intake stroke. Absolute barometric pressure is equal to Relative barometric pressure only at sea level.
