For use with the SmartSpark ignition, the RTD-1 retard control is required for driver adjustable retard (GPI3 analog retard mode).
For use with the CD-1 ignition, the RTD-1 retard control is required for boost timing retard (BTR) mode and GPI1 analog retard mode. A manifold absolute pressure (MAP) sensor is also required for boost timing retard mode.
