ThunderMax for 2018 - 2020 Softail® Models

Part Number: 309-589 ThunderMax is an award-winning, performance ECM designed specifically for EFI-equipped Harley-Davidson® motorcycles. This advanced, stand-alone tuning system uses proprietary AutoTune technology with wide-band oxygen sensors to deliver unmatched performance, rideability, and adaptability. The ThunderMax ECM comes fully assembled, ready to install, with no wire-cutting or splicing required. Simply replace the factory ECM and oxygen sensors, load a base map, and ride. Installation is quick, and the system immediately begins tuning itself to your bike. With built-in knock control for timing adjustment, ThunderMax offers precise spark management in real time. It retains full factory functionality and works seamlessly with factory systems. Wide-band O₂ sensors continuously read the air/fuel ratio, automatically making live adjustments across every throttle position and RPM range. No dyno is required, and once you key off, all changes are instantly written to the ECM. T