The Dyno Test or Where Do Engine Stats Come From

Ever wondered how they get the fuel economy (MPG) numbers that you see for vehicles and the engine performance stats like torque? The numbers are produced by an instrument called a dynamometer (or dyno for short). It basically consists of a platform with rollers that the wheels of a car will sit on. The dyno has sensors that allow it to measure the torque applied to the rollers by the car and the rotational speed of the rollers. Knowing both torque and rotational speed allows the calculation of the power output as the product of the torque and rotational speed. The video above shows several dynos in action. Now you know where fuel economy statistics come from!