Closed-loop boost operates in up to four stages depending on current conditions:
Stage 0 – Disabled
Regulation is off. This occurs if the engine isn't running, target boost is zero, external input disables control, or meth injection forces low boost.
Stage 1 – Spool-Up
MAP is well below target (by more than spool threshold).
The ECU commands maximum solenoid duty to spool the turbo quickly.
No PID regulation is active.
Stage 2 – Approaching Target
Boost is rising and within spool threshold but not yet close to target (based on control threshold).
Open-loop duty from the boost duty table is used.
PID is partially active: only D-term is applied to avoid overshooting.
Stage 3 – Closed-Loop Active
Boost is near target.
Full PID control is active (P, I, and optionally D).
This stage ensures precise and stable regulation.
The system transitions automatically between stages based on MAP and target boost levels.
Note: The current boost control stage (0–3) is shown in the RealTime Value Boost stage parameter. This helps visualize and diagnose what part of the regulation logic is currently active.
