This allows the ignition timing to be adjusted with respect to the engine intake air temperature. It is common to reduce ignition advance at high intake temperatures to avoid detonation. To do this, enter negative values in the higher temperature cells (eg above 100ºC).
The IAT ignition trim function does not necessarily have to be used for ignition adjustment based on intake temperature. If Setup is set to 3D the table can be setup to trim ignition depending on what is selected as the tables X and Y axis parameters.
The amount of ignition trim applied at runtime is displayed by the IAT Ignition Trim parameter found under the Ignition tab of the Runtime Values window (F12 key).
IAT Ign Trim Settings:
Set to 2D Table for a single row trim table, set to 3D Table for a two axis trim table or set to OFF for no IAT based Ignition trim.
If a 3D table is used, the X and Y axis are configurable.
The value entered into each cell represents the amount of ignition in degrees BTDC to be added at that particular intake air temperature, entering negative values will remove that amount of ignition advance at that particular temperature.