The dyno here at Fluid MotorUnion is an all-wheel-drive Dyno Dynamics Dynamometer. Dyno Dynamics is an Australian based company and is the largest dyno manufacturer in the southern hemisphere. Their dynos are not inertia style dynos like Mustang Dyno or DynoJet. They are Eddy Current dynos. This style of dynamometer produces braking torque using the principle of eddy currents induced in a rotating metallic disk, immersed in a magnetic field. A strain gauge load cell on all models provides torque measurement capabilities for precise calculations of power. The rollers are there to provide resistance, not measure power. The power calculation is determined by through the voltage that is required to create eddy currents that are strong enough to match the output of the vehicle. A certain level of voltage indicates a specific amount of torque. Therefore for accurate, repeatable numbers, you want the car climbing the rollers as much as possible without coming off in order to accurately measure the full potential of the vehicle. We use four ratchet straps to secure cars on the dyno, two limit its forward motion, and two for keeping it on the rollers. Each of these straps are rated for 2,000 lbs of force.
This style of dyno is actually regarded as the most accurate way to measure wheel horsepower and torque. However, they are less common than higher reading dynos like Mustang dynos and Dynojet dynos. Since they typically read lower than those other brands the Dyno Dynamics dynos are known as “heartbreaker” dynos. For example, a Dodge Challenger Hellcat, which has 707 HP at the crank puts down about 490 WHP on our dyno after drivetrain loss. However, this same model car has been documented on a DynoJet putting down 665WHP. But truth be told top HP runs dont really mean anything from a dyno as due to atmospheric conditions, weather, style of dyno, etc they’re all going to read differently. Dynos are useful for comparing baseline (Before mods and tune) graphs to after mods and tune graphs in order the measure the gain of those modifications. They also provide a safe controlled environment for logs to be taken when tuning.
Below are a few examples of this taking place. You can see the car sitting down in the rollers at the beginning of the run, but as it starts to make power you can see it climbing the rollers almost up to the apex.