Manifold Absolute Pressure
Air pressure measured inside the intake manifold, downstream of the throttle body. This is the pressure the engine actually breathes.
Why it matters
On BM3 three-signal setups, MAP differs from pre-throttle boost by the throttle body restriction (typically 2-6 PSI at WOT). MAP is used for boost control deviation analysis because the ECU targets manifold pressure, not pre-throttle pressure.
What to look for
MAP should closely track manifold target. A gap between pre-throttle boost and MAP indicates throttle restriction, not a boost control problem.
Related terms
The boost pressure the tune is requesting. Actual boost should track this closely.
The measured boost pressure in the intake manifold at any given moment.
Boost pressure measured between the turbo compressor outlet and the throttle body. The turbo's direct output before any throttle restriction.
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