ThunderMax ECM with Integral Auto Tune System for Harley-Davidson
The ThunderMax ECM replaces the factory Harley-Davidson engine control module and eliminates the need for dyno tuning by adjusting your air/fuel ratio in real time on every ride. Riders gain sharper throttle response, a cooler-running engine, and noticeably smoother power delivery whether the bike is stock or built with aftermarket exhaust and cam upgrades.
Key Features
- Integral Auto Tune: Continuously monitors and adjusts AFR targets while you ride – no manual mapping required.
- Wide-Band Accuracy: Includes two 18mm Bosch wide-band oxygen sensors for precise data feedback.
- Knock Correction: Actively monitors for detonation and adjusts ignition timing on the fly for added protection and optimized performance. (M8 and newer models.)
- User Adjustable: Allows modification of idle speed, rev limit, and speedometer calibration via TMax software.
- Adaptive Learning: Automatically compensates for ambient weather changes, altitude, and exhaust modifications.
- Diagnostic Capable: Reads and clears diagnostic trouble codes (DTCs) and logs performance data.
- Made in the USA: Engineered and manufactured with high-quality components.
Technical Specifications
- System Type: Wide-Band Closed-Loop EFI System.
- O2 Sensor Thread: 18mm x 1.5 (Requires 18mm bungs in exhaust).
- Tuning Resolution: Adjusts every 256 RPM and 1.5 degrees of throttle position.
- Mounting: Direct OEM Replacement Footprint (Fits stock ECM caddy).
- Connection: Plug-and-Play Factory Harness Connectors (No splicing required).
- Compatibility: Supports Turbo, Nitrous, and Supercharger applications.
- Includes: ECM, wideband oxygen sensors, USB cable and instructions.
Fitment Notes
- For fuel-injected Harley-Davidson motorcycles only – this system is not compatible with carbureted engines.
- Center Cooled Models: The 2023.5-Up CVO and 2024-Up Touring models with the Center Cooled engine and new fairing design require the separate 2023.5-Up variation. That unit fully preserves all factory features including ride modes, cruise control, navigation, and Wi-Fi connectivity.
- RDRS / Traction Control Models: Bikes equipped with RDRS (Reflex Defensive Rider Systems) or Traction Control – which includes all 2019-2020 Trikes, optional on 2020 Touring, and standard on most 2021-Up platforms – require a free RDRS firmware load from Thundermax tech support before installation. The hardware is the same; only the firmware differs. Contact us or email support@thunder-max.com with your VIN before installing.
- Exhaust Requirement: This system uses 18mm wide-band O2 sensors. If your exhaust pipe is equipped with smaller 12mm ports (common on 2010-Up Touring, 2012-Up Softail/Dyna, and 2014-Up Sportster), you MUST install 18mm bungs or use an exhaust system designed with 18mm ports.
- Map Loading: System requires loading a base map via a Windows PC prior to first start (Software and USB cable included).
- Not all ThunderMax ECU models are registered for public road use in all states; verify emissions compliance for your state before installing.
- Review the Fitment tab for the complete year and model breakdown across all available variations.
Harry Speckman –
no mess, “easy” to install, works great
Joe Pinedo Jr –
Email for technical support and they helped me thru every step.
Job –
First off let me say I’m a mechanic. My Bike has never ran this good. The auto tune is amazing. Runs so clean and smooth. Very easy to set up and load tune. Don’t waste your money on the other junk (power commander) unless your trying to blow up your bike. will definitely purchase one for my next bike(s)
Chris M. –
Correct part and and great service
Gregory O. –
Closed loop auto tune is best. No going to dyno after mods.
Jon K. –
Product is awesome and has made my bike preform even better then before.
Rene Ramos –
Awesome tuner. Do it yourself.
Greg C. –
Very simple installation
Chad Lewis –
Can’t wait. Exactly what I ordered.
Marques –
Awesome product!
Dale Pash –
Easy to install just follow the instruction. Plenty on youtube for visual affect. Customer support is outstanding!
Larry Crow –
Best price i could find had to add 18mm bungs no big deal with a little luck ill be riding in a few days then I’ll send video and smile on face
Anonymous –
Good product would recommend.plus great price to
Alan P. –
Good price, easy order, fast delivery
james crews –
Great Product Best Pricing
Edward U. –
The Thundermax ECU was relatively easy to install and load the base map. I had to have 2 new O2 sensor bungs welded onto my exhaust because the locations for the previous bungs wouldn’t work (Sawicki RT Shorty) on my 2022 Lowrider ST.
Anonymous –
Quality
Parley Mortensen –
So far I am very happy with my purchase.
Bruce S. –
Great efficient service, no hassles to send to New Zealand either. Great results.
Peter S. –
Hard to find item made easy. Thanks!