ThunderMax Base Map Selection and Loading

A Base Map is the starting calibration file used by TMax Tuner Software to match your ThunderMax EFI module to your motorcycle's configuration. It contains pre-configured fuel, spark and idle-control values for a bike with similar engine size, injectors, throttle body and exhaust. It gives the module a starting point to learn and fine-tune from as the bike runs.

Each map in the library was developed and tested using real-world combinations. Selecting the right map helps the system adapt to your bike for smoother startup, better throttle response and faster AutoTune adjustments. Before making tuning changes, start with the map that best matches your configuration. The system's learning functions and tuning tools can then refine the tune for your exact setup and riding style.

View / Download the Base Map Selection and Loading Guide — PDF

Before you begin

• Confirm the motorcycle's components: engine size, cam specifications, throttle body size, injector size, exhaust and other components.
• Ensure the PC is charged and connected to power.
• Maintain the motorcycle battery with a low 5-amp charger.
• Confirm TMax Tuner Software is installed and establish a stable USB connection.

Choose the correct EFI Maps family

The EFI Maps section organizes base maps into five main categories. Each represents a motorcycle family or wiring family. Select the correct category for your motorcycle's system architecture:

• Big Twin M8 Maps (Milwaukee-Eight)
• Big Twin Maps (07-Up Twin Cam / TBW / TBC CanData)
• Big Twin TBC Maps (1995-2017 / Marelli / HD Twins / Evo)
• V-Rod Maps
• XMS Map Listing (Narrow Band)

Watch the Base Map Selection video

Watch “Base Map Selection — TMax Tech Tips” for a visual reference.

Step 1: Open the correct Base Map library

From the main menu, select EFI Maps, then select the subcategory that corresponds to the motorcycle.

EFI Maps menu: select the motorcycle family.

Step 2: Update the map listing

Click Update at the bottom right of the map library. The illustrated button is labeled Update All Maps. The software automatically updates the Base Map library. Allow the update to complete.

Update All Maps refreshes the Base Map library.

Step 3: Filter by engine size

The library shows the maps for your engine type. Under Engine Type, scroll to the corresponding displacement. Right-click an entry with that displacement to show only maps created for that engine size.

Engine Type: right-click the matching displacement.

Step 4: Filter by camshaft

The list should now contain only maps for the selected engine size. Scroll right to the Cam heading. Find a cam profile similar to your engine configuration, then right-click that cam to narrow the library view again.

Cam Specification Chart: Cam Chart — PDF.

Map list after the engine-size filter: select a similar cam profile.

Step 5: Filter by throttle body and injectors

The list should now contain maps for your engine size and cam profile. Scroll left to the Throttle heading. Find the correct throttle-body and injector combination, then right-click it to narrow the library view again.

Fuel Injection — How to Identify Injectors: Fuel Injector Specs — PDF.

Map list after the cam filter: select the throttle body and injectors.

Step 6: Select the closest exhaust

With the other selections applied, find the Exhaust heading. Right-click the exhaust closest to your bike.

Exhaust note: The ThunderMax ECM is an auto-tuning device and will dial appropriate AFRs to your engine's exhaust. Matching the exhaust exactly is not needed in most cases.

Throttle and injector selection: continue with the closest exhaust.

Step 7: Select and load the Base Map

Double-click the desired Base Map to open the Base Map Name Encoding dialog. Check every field to confirm the correct map is selected, then click Load Base Map. The selected map and a dialog box will appear on screen.

Check each field, then select Load Base Map.

Step 8: Confirm writing the selected map

When asked whether to WRITE the selected Base Map to the ThunderMax module, click Yes if no other Base Map changes are needed.

Write selected Base Map prompt.

Step 9: Set Automatic Compression Release values

Read the Setting ACR values screen and make the appropriate selection for your Automatic Compression Releases (ACRs).

Check the motorcycle first: Big Twin or M8 103 and up generally have factory ACRs. Confirm whether your motorcycle is equipped with ACRs before selecting this setting.

The illustrated ACR setup dialog provides these additional instructions:

• Year 2012 or newer bikes with 103 or larger engines have ACRs.
• 2011 motorcycles equipped with the 103 POWER PAK option also have ACRs.
• Other motorcycles may or may not have releases unless they were added.
• If the motorcycle sets an ACR code, turn the ACRs OFF.
• If you are unsure, respond No. Compression releases can be turned ON or OFF later in basic settings.

Automatic Compression Release setup: confirm the motorcycle has ACRs.

Step 10: Allow the map to finish writing

Allow the software to write the Base Map to the ECM. A progress bar appears while the transfer is in progress.

Writing map progress.

Step 11: Confirm the map was written

Confirm the Module Map Write Status message reports that the current displayed map was successfully written to the module. Then continue with module initialization.

Base Map written successfully.

Step 12: Initialize the module

Initialization is required after a new installation or interruption of 12-volt ECM power. This sequence applies to all module families and model years.

1. With Run ON and the engine stopped, turn the ignition ON for 20 uninterrupted seconds.
2. Turn the ignition OFF for 30 seconds.
3. Repeat until you have completed three ON/OFF cycles in total.
4. Turn the ignition ON and start the engine. Let it idle on its own for 15 seconds.
5. Turn the ignition OFF and restart.

Need help selecting or loading a Base Map?

Contact ThunderMax technical support or email support@thunder-max.com with any questions.

Based on the ThunderMax “Base Map Selection and Loading” guide, version 1.9, dated October 27, 2026.