The DynoCal system for auditing chassis roll dynamometers has been developed for the California Bureau of Automotive Repair. It evaluates performance of new dynamometer designs and operational dynamometers in the field. The system includes a 50 kW electric motor with torque, thrust, and speed instrumentation. It functions as a vehicle to drive the chassis rolls under computer-controlled test modes. A trailer transports the system and houses the battery power supply, chargers, flux vector power converter, and computer. The controls are user-friendly, with graphic displays and high-speed data acquisition. Among other functions, this unique test instrument measures dynamometer road load and inertia simulation accuracy.