Dyno Chart Information
A chassis dynamometer also known as a dyno is typically used to measure the horsepower and torque of a vehicle's engine. For example a rear wheel drive car is strapped to the dyno with its rear wheels in contact with the dyno rollers. The driver accelerates the vehicle on the dyno to a determined rpm in order for the dyno instrumentation to measure power at the wheels. A calculation factor can be used to scale-up the wheel horsepower value to a flywheel horsepower value. Most vehicle manufacturers advertise flywheel values.

Flywheel horsepower can also be measured directly without using a drivetrain loss calculation by removing the engine from the vehicle and testing it on an engine dyno. When tuning a multitude of vehicles this method can be cost prohibitive in the aftermarket.

It can be said that often there is a variation between one chassis dyno and another. A major difference between chassis dyno's is the amount of load they impose on the vehicle. Application of load during dyno testing is important for simulating on-the-road conditions for safe ignition timing and air fuel trims. VF-Engineering uses an in-house Dynojet 224 XLC eddy current load bearing dyno for all its testing. GIAC who exclusively write VF-Engineering supercharger software also test vehicles on their Mustang MD500-SE 4 wheel drive chassis dyno.

All dyno's advertised on the VF site show SAE power measured at the wheels as this is the exact output displayed by the Dynojet computer. Wheel horsepower numbers are typically scaled up by 15% to arrive at flywheel numbers. Dyno chart numbers have been multiplied by 1.15 to provide estimated flywheel values. SAE is 98.63% of DIN. Power figures may vary from car to car depending on their condition.