The ECU needs an input of engine load. The Omex ECU can use an input of either throttle position or manifold absolute pressure (MAP). Most normally aspirated engines will use an input of throttle position as this gives excellent throttle response. Forced induction engines need to use MAP as there is no direct relationship between throttle angle and engine load due to the variable of boost pressure. However, forced induction still requires throttle position sensor (TPS) input for idle condition information. In some cases a MAP sensor can be used on a normally aspirated engine for load.
The rating of MAP sensors is absolute, not boost pressure. Therefore a 2bar sensor is for up to 1bar boost and a 3bar for up to 2bar boost. Normally aspirated engines if using manifold pressure for load would use a 1bar sensor.