The boost/MAP pressure sensor compensates for changes in manifold pressure, most commonly used with turbo applications. The sensor input is 0 - 5V, it is fully calibratible by the end user. The ECU will normally comes with calibration either for the MBE/GM sensor (car engine) or standard Suzuki/Nippon Denso sensor (bike engine). The ECU can make changes to fuelling & ignition according to pressure.