What are the advantages and disadvantages of an inertia dyno compared to a water brake?
An inertia dyno uses the inertia of a large flywheel or drum to absorb the power from the engine and slowly accelerate through the RPM range. By knowing the inertia and measuring the acceleration rate, torque and HP can be calculated. An absorber dyno (water brake, hydraulic pump, eddy current, etc) absorbs the power of the engine in some type of “pump” which raises the pressure of the fluid, eventually turning the power into heat. The amount of torque required to keep the housing of the “pump” from rotating is also the amount of torque the engine is producing. Both methods produce accurate results, but each has advantages and disadvantages.
