Hardware in the loop (HIL) simulation enables experimental study of prototype hardware systems or control algorithms via real-time interaction between physical hardware and virtual simulations. As a result, this method is a particularly valuable tool for hybrid vehicle powertrain analysis. In the case where novel or prototype hardware is being examined, it is often necessary to scale the signals in and out of the prototype system in order to represent production-sized components. This scaling process is usually done in an adhoc manner. In this work, a formal method is presented that derives appropriate input/output signal conditioning to correctly scale electric vehicle components, namely the electric motor and battery subsystems.