Engine Dyno Information

An engine dyno can measure exact changes in power output levels during performance tuning.

When testing a car's power output during performance tuning, mechanics use a device called a dynamometer, or dyno. An engine dyno is one of the two main types of dynamometers, measuring power by hooking the engine up to one of several devices designed to measure the engine's ability to do work.

Types

The two main types of engine dynos are the water brake dyno and the electric dyno. Each provides exact measurements of an engine's horsepower and torque outputs.

Operation

For a water brake dyno, the engine is hooked up to a fluid coupling where water is pumped in to provide a braking effect against the rotation of the crankshaft. This device is similar to a torque converter and measures power output. In an electric dyno, the engine is used to power an AC or DC motor, which then dissipates heat and measures current.

Engine Dyno vs. Chassis Dyno

A second type of dynamometer, called a chassis dyno, is sometimes used to measure power output. Unlike an engine dyno, measuring power output with a chassis dyno can be done with the engine still installed in the car. The chassis dyno measures power at the wheels instead of at the engine's crankshaft, and is thus subject to variations based on power losses within the drivetrain.

References

• Circle Track: Dyno Tech - Technology Transfer, Part V