These boost control parameters determine how the ECU controls the boost control solenoid.
Enabling Boost Control
The purge valve is used to run the boost control solenoid, as it is a duty cycle controlled output.
Settings
These settings contain the solenoid characteristics.
Configuration - allows for normally open and normally closed solenoid setups. If your solenoid is connected so that minimum boost is made with the solenoid off, set this to maximum boost at 100% duty / normally closed.
Minimum and maximum duty cycle - set the solenoid duty cycle limits.
Solenoid activation pressure - sets the point where ECU starts to use the solenoid to control boost pressure. Normally this can be set a little below the minimum boost pressure in order to minimum wear on the solenoid.
Sets the frequency of the boost control solenoid output.
Control Method
There are two control methods: a fixed duty output, where the solenoid is run at a fixed duty cycle and boost will be about the same in each gear, and a gear based duty cycle where boost can be varied in each gear.
A fixed duty cycle has one parameter - the duty cycle. When the settings are configured for a normally open solenoid the actual duty cycle is inverted so that a higher duty cycle will increase boost.
A gear based duty cycle uses two additional tables to determine duty cycle. First the Boost vs Gear table is used to find the target pressure for the current gear, then the Pressure vs Duty Cycle table is used to calculate the solenoid duty cycle to reach the target boost.
Pressure vs Duty Cycle
The Pressure vs Duty Cycle table contains a lookup of pressure valves which correspond to a solenoid duty cycle. The values for this table must be set by using a fixed duty cycle (see Control Method) and noting the resulting manifold pressure. Note that different ambient conditions will result in slightly different boost pressures for the same duty cycle.
Low/High Boost
This allows two different boost settings (by gear) to use used, based on a switch input.
Boost by Gear
These tables set the target boost for rpm and gear. The pressure units are determined by the combo box under Settings.
Quick Spool
This tables opens up the boost control solenoid completely and closes the waste gate to build up boost faster. Once the pressure reaches the value in the table the solenoid goes back to its normal duty cycle. When using this feature, we recommend setting the solenoid activation pressure to 1 pound of boost, and the quick spool pressures to 1 or 2 pounds below target boost levels. To disable quick spool, set the values in the table lower than the solenoid activation pressure.