Absolute Pressure refers to pressure measurements taken on a scale where Absolute Vacuum0 equals 0.

• Atmospheric Pressure: Approximately 14.7 psi at sea level when measured as absolute pressure.
• Boost Pressure: 10 psi of boost is approximately 24.7 psi absolute (14.7 psi atmospheric + 10 psi boost).
• Tire Pressure: 30 psi of tire pressure is approximately 44.7 psi absolute (14.7 psi atmospheric + 30 psi tire pressure).

ECU Mapping and Absolute Pressure#

When tuning, ECU editors typically display values in Absolute Pressure.

Note

Column 10 in standard mapping software typically represents atmospheric pressure. Values may appear slightly lower due to interpolation or minor vacuum present even at Wide Open Throttle (WOT).

Column 1 is arbitrary and does not represent true zero (absolute vacuum).

Reference Data#

For specific operating ranges and voltage scaling, refer to the MAP Sensor0 documentation to determine the maximum pressure limits of OEM sensors.

Example of absolute pressure scaling in ECU tuning software