ThunderMax 2023.5-Up Touring® Center Cooled Models VVT or non-VVT)
ThunderMax 309-605 ECM for 2023.5-Up Center-Cooled Touring® Models
For 2023.5-up Harley-Davidson® Touring models with center-cooled Milwaukee-Eight® engines. Compatible with VVT and non-VVT applications.
Replace your factory engine control module with ThunderMax EFI management and AutoTune technology. The 309-605 combines a replacement ECM with wide-band oxygen sensors to monitor exhaust oxygen and adjust fueling as you ride.
Check your application: For 2021-up Road King®, 2021–2024 Ultra®, and 2021–2025 Trike® models, see ThunderMax 309-591.
How AutoTune works
Select and load a basemap suited to your motorcycle’s engine, exhaust, and other modifications. After installation and initial setup, AutoTune uses oxygen sensor feedback to make ongoing air/fuel ratio corrections.
The basemap provides your starting calibration. AutoTune refines fueling from that starting point as you ride.
Key features
- Complete replacement ECM: Replaces the factory module and connects to the motorcycle’s wiring harness.
- Wide-band AutoTune: Uses 18 mm oxygen sensors to monitor exhaust oxygen and make fueling corrections.
- Knock correction: Uses the factory knock sensors to automatically adjust ignition timing when knock is detected.
- Factory feature compatibility: Retains operation of ride modes, Wi-Fi, and navigation on equipped models.
- Barometric compensation: A built-in sensor accounts for changes in altitude and ambient air pressure.
- Adjustable settings: ThunderMax software provides access to air/fuel targets, ignition timing, idle speed, rev limits, speedometer calibration, and other tuning parameters.
- Diagnostics and data logging: Monitor engine information and record operating data to support troubleshooting.
What’s included
- ThunderMax ECM with AutoTune
- Wide-band oxygen sensors
- Plug-in harness
- USB communication cable
Check your exhaust before ordering
ThunderMax requires compatible 18 mm oxygen sensor ports in the exhaust head pipes. Verify that your exhaust has suitable ports before installation.
If your exhaust has smaller ports or no suitable sensor ports, modifications may be required. Weld-in sensor bungs are not included.
Installation and setup
Review the application-specific installation instructions before beginning. Installation includes replacing the factory ECM, fitting the oxygen sensors, and completing the software setup.
Download ThunderMax software · View 309-605 installation instructions
This product is intended for "RACE READY" vehicles only and is not for sale or use on vehicles otherwise subject to emission control requirements. In the state of California, this product should not be used on any vehicle that is registered for use on public roads. Please view the ThunderMax 50 application guide for "STREET APPROVED" & ARB compliant products.