scion  water brake absorber is sometimes mistakenly called a "hydraulic dynamometer. Water brake absorber are relatively common, having been manufactured for many years and noted for their high power capability, small package, light weight, and relatively low manufacturing cost as xb compared to other, quicker reacting "power absorber" types. Their drawbacks are that they can take a relatively long period of time to "stabilize" their load amount and the fact that they require a constant supply of water to the "water brake housing" for cooling. In many parts of the country, environmental regulations now prohibit "flow through" water  xb and large water tanks must be installed to prevent contaminated water from entering the environment water xb.

• The schematic shows the most xb common type of water brake, the variable level type. Water is added until the engine is held at a steady rpm against the load. Water is then kept at that level and replaced by constant draining and refilling, which is needed to carry away the heat created by xb  absorbing the horsepower. The housing xb attempts to rotate in response to the torque produced but is restrained by the scale or torque metering cell which measures the torque xb .

A Brake dynamometer applies variable load on the engine and xb  measures the engine's ability to move or hold the rpm as related to the "braking force" applied. It is usually connected to a computer which records the applied braking torque and calculates the power output of the engine based on information from a "load cell" or "strain gauge" and rpm speed sensor xb water.

An Inertia dynamometer provides a fixed inertial mass load and calculates the power required to accelerate that fixed, known mass and uses a computer to record rpm and acc. rate to calculate torque.The engine is generally tested from somewhat above idle to its maximum rpm and the output is measured and plotted on a graph xb.