Under normal circumstances a 3D Fuel Table is sufficient, usually with engine speed on one axis, load (typically represented by TP(Main) or MAP) on the other axis and the fuel 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.
An example of a possible application would be to correct VE as a function of barometric pressure (eg to correct for turbo charger efficiency changes).
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 Fuel Trim open the Fuel tab of the Runtime Values window (F12 key).
When configured as Overlay Table, the Dual Fuel Table effectively adds a 6th user defined fuel tuning dimension (6D). As the Dual Table is larger than the 4D and 5D tables it is the preferred table for fuel overlay tuning (if switchable fuel maps are not required).
4D/5D Fuel Table Settings:
The 4D or 5D tables may be enabled or disabled by selecting ON or OFF.
Allows the 4D or 5D Fuel 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 Fuel 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 Fuel Mode is set to ON.
This table works as an adjustment to the main fuel table. As with most Link ECU correction tables, the 4D and 5D Fuel Tables are applied as a percentage of the base pulse width. As the base pulse width is calculated using the numbers in the main fuel table, the 4D/5D Fuel Table numbers effectively act as a percentage of the main fuel table. Another way to word it is: Putting 10% in the 4D Fuel Table is the same as changing the Main Fuel Tables number by 10%.
4D and 5D Fuel 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.
Example:
A reduction in the Main Fuel Table from 50 to 45 is a 10% change. The same effect can be achieved by leaving 50 in the Main Fuel Table and putting -10% in the 4D Fuel table. 50 minus 10% of 50 equals 45 or 50 - (50 * 10%) =45