Under normal circumstances a 3D Ignition Table is sufficient, usually with engine speed on one axis, load (typically represented by TP(Main) or MAP) on the other axis and the ignition advance value as the third axis. This 3D mapping will be very familiar to the average tuner and a 3D surface representing the ignition timing can be easily visualized or physically displayed using a Surface Graph.
In special cases 3D mapping may not be adequately flexible to cope with all operating parameters, Multi-throttle turbo charged engines are typically an example of this. With the throttle wide-open at a MAP value of 200kPa and an engine speed of 5000rpm the engine will have considerably different timing requirements than with the throttle half open and the same MAP and engine speed. In this case the 4D ignition table may be used. This second table may be spanned using throttle position (TP(Main)) on the load axis.
The 4D and 5D Tables allow a way to achieve higher dimensional (4D, 5D, 6D) mapping to cater for the most complex tuning situations. This concept is difficult to visualize and tuning in this mode will consume more time and as a result of this tuning using the 4D and 5D tables is recommended for advanced tuners only.
To view the current amount of trim being applied by the 4D or 5D Ign Trim open the Ignition tab of the Runtime Values window (F12 key).
When configured as Overlay Table, the Dual Ignition Table effectively adds a 6th user defined ignition tuning dimension (6D). As the Dual Table is larger than the 4D and 5D tables it is the preferred table for ignition overlay tuning (if switchable ignition maps are not required).
4D/5D Ignition Table Settings:
The 4D or 5D tables may be enabled or disabled by selecting ON or OFF.
Allows the 4D or 5D Ignition Table to become active only under certain conditions, this is useful if an external switch or switching output is required to activate the table (eg switching in the 4D Ignition Table when the NOS solenoid becomes active). If the table is required to be always active set this adjustment to Always ON.
This setting is only available when 4D/5D Ign Mode is set to ON.
This table works as an adjustment to the main ignition table. The numbers entered in the table are degrees before top dead centre (BTDC) and are ADDED to the main ignition table. 4D and 5D Ignition Tables can have their X and Y axis parameters selected and their row/column locations adjusted. To do this, click on the table and press the X key or right click on the table and select Axis Setup.