For Configuring the MAP sensor

[lailarry]

Hi, My car is Audi RS4 B5 2001. I check my MAP sensor and HFS4-V2 manual that confusion. My MAP sensor is the signal which the sender generates is a pressure-proportional voltage ranging from 0 to 5 volts. At atmospheric pressure (14.7 psi or 1.01 bar at sea-level), the voltage is approx. 1.88 volts. The absolute maximum pressure reading is approximately 2.55996 bar absolute (22.45 psi), which should read approximately 4.76 volts.
The manual P21 Configuring the MAP sensor type: (Three types of MAP sensors can be selected)
(a) Absolute (default): This can be used for any sensors with 0-5V output, such as throttle position, mass air flow sensors etc.
(b) 2-bar MAP sensor: Select this link to convert a 2.5 bar MAP sensor to read from atmospheric to 22psi full scale 0-5V output.
(c) 3- bar MAP sensor: Select this link to convert a 3.5 bar MAP sensor to read from atmospheric to 36psi full scale 0-5V output.
Which one is my car setting ? (a) or ( b). Also what is different between each ? Thanks

[Richard L]

For the HFS4-v2, 2.5bar is the default factory setting. It will read up to ~22.5psi over 1 ATMOS.

Your setting should be B (default). It translates your sensor from 1.88-4.76V to 0-5V for the internal circuitry.

The difference between a,b and c is the voltage at 1 atmosphere. It is used internally as a boost reference from 1 atmosphere.

[rexTI808]

In the subject of map sensors i was wondering if the setting for a 3.5 bar map sensor would be inaccurate as i currently have a 3bar map installed.

[Richard L]

There is no difference as far as the 0-5V output signal is concerned. The 3/3.5 bar map sensor only affects the "threshold" trimmer if you are triggering by MPS.