Some ECU adjustment is needed to keep the fuel program happy with the increased airflow. URD's preprogrammed performance calibration unit also addresses engine timing and is plugged directly into the under-dash stock engine computer. There is also one additional fuel injector installed, also controlled by the calibration unit. In previous testing URD has achieved a 95 hp gain at the rear wheels of a two-wheel-drive truck with only 6 psi of boost. Though we didn't get a chance to dyno our FJ, we did feel that we had excellent performance from the supercharger.