ECM Replacement with AutoTune

The ThunderMax 309-591 is a performance-driven, award-winning ECM designed as a stand-alone replacement for the factory ECM in EFI-equipped Harley-Davidson motorcycles. At its core, the ThunderMax utilizes proprietary AutoTune technology and a closed-loop control system to continuously monitor and perfect your motorcycle's air/fuel ratio in real time. With fueling points mapped every 1.5° of throttle and every 256 RPM, it offers precise control for smooth, consistent performance across all riding conditions. A built-in barometric sensor automatically adjusts for changes in altitude and ambient air pressure. The 309-591 also incorporates knock correction for on-the-fly ignition timing adjustments, further enhancing performance. Unlike many aftermarket tuners, this system fully supports factory functions, ensuring you retain the original conveniences of your Harley-Davidson. Riders can choose to run a pre-loaded basemap with AutoTune handling adjustments or use the free ThunderMax software to fine-tune AFR maps, ignition timing, startup fuel, idle speed, rev limits, and speedometer calibration. The system also provides robust data logging and diagnostic capabilities for detailed engine performance analysis. The result of using the ThunderMax 309-591 is sharper throttle response, improved rideability, and a deeper, tuned exhaust note. It is compatible with high-performance cams, turbo, nitrous, and supercharger applications. ThunderMax ECMs use 18mm O₂ sensors; if using a factory exhaust with 12mm ports, 18mm bungs may need to be welded in (bungs not included). This product is intended for "RACE READY" vehicles only and is not for sale or use on vehicles subject to emission control requirements. In California, it should not be used on any vehicle registered for public roads.