Part Number: 309-591

*Excludes 2023-2024 CVO®(VVT)  and HELIX Platform

*Trike Models with RDRS: Please email support@thunder-max.com prior to installation for an updated firmware file.* 

ThunderMax is an industry award winning, performance ECM designed specifically for EFI equipped Harley Davidson® motorcycles. This highly advanced, stand-alone tuning system utilizes proprietary AutoTune technology with wide-band oxygen sensors to deliver unmatched performance and rideability. ThunderMax comes 100% assembled, ready to install with no wire-cutting or splicing required. Simply replace the factory ECM and oxygen sensors, load a map, and enjoy your new ride!

Every degree and a half of throttle; every 256 RPM, there is a fueling point that is automatically adjusted. That means more control and a smoother running engine. With the built in barometric sensor you never have to think about ambient air changes. WideBand O2 sensors constantly read the Air Fuel Ratio and give live, real time feedback to the ECM. That means, no “accepting” the changes made to the map, once you key off the changes are written. The ThunderMax ECM is fully adjustable with our ThunderMax tuning software or can be used just by loading a basemap. The choice is yours.

ThunderMax® with Wide Band AutoTune is purpose-built to deliver uncompromising performance with advantages not possible with post-fuel or flash systems. ThunderMax’s Wide-Band AutoTune system will keep any engine properly tuned even with wide swings of changes of ambient air conditions.

ThunderMax’s® Wave Tune AutoTune analyzes, adjusts and anticipates the needed air/fuel correction via  wide-band oxygen sensors processing at warp speed during to assure every combustion cycle is efficient, making any necessary adjustments to the injector pulse width to achieve the target air/fuel ratio while compensating for tolerance stack of injector flow, variance of fuel rail pressure and ambient air conditions.

*System Supports RDRS on 2019-2020 Models!

Plus these features:

• Idle Speed & Rev Limit

• Accel Pump Simulation

• Start Fuel Pulse

• Decel Pop Control

• Speedometer Calibration

• Read Diagnostic Codes

• Running Statistics / Logs

• Engine Temp Alarm

• Live Monitoring & Recording

• Digital Tech Compatible

ThunderMax® employs industry-leading tech support process though the Auto Support function in the software to directly connect you with a TMax support agent with just a few clicks of a mouse!

The factory exhaust use 12mm narrow-band sensors.  Add 18mm bungs when using the factory pipe.

ThunderMax® is made in the USA by Thunder-Heart Performance Corp in White House, TN.

Download the ThunderMax® software for free! CLICK HERE!

Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.