Closed-Loop Boost Control Without Chasing the Target
Closed loop should refine a stable open-loop system — not rescue an inconsistent wastegate, solenoid or boost reference.
Build a repeatable open-loop baseline
Before feedback is enabled, the wastegate spring, plumbing and duty table should produce predictable boost. Test across relevant gears and rpm because exhaust energy and engine load change the result. If identical duty creates different boost on every run, feedback will only chase the inconsistency.
Give feedback limited authority
A sensible controller corrects a small remaining error around a good base table. Limits on positive and negative correction prevent it from hiding a failed hose, sticking gate or incorrect target. Proportional, integral and derivative terms should be added gradually while watching overshoot and settling time.
Safety remains independent
Boost control is not overboost protection. The ECU still needs separate limits for manifold pressure, fuel pressure, lambda, temperature and, where appropriate, turbo speed. The safe response may include closing the throttle, reducing boost duty, cutting torque or ending the run depending on the system.
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