Understanding Boost Pressure
An overview of boost pressure, defining it as intake manifold pressure exceeding atmospheric pressure and clarifying the distinction between boost and absolute pressure.
Boost is defined as the condition where the pressure within an engine's intake manifold exceeds atmospheric pressure.
Important
Boost pressure is measured relative to atmospheric pressure. It is critical to distinguish between boost pressure and absolute pressure; 1 psi of boost is not equivalent to 1 psi of absolute pressure.
Pressure Definitions
- Atmospheric Pressure: The ambient pressure of the surrounding air, typically measured at 14.7 psi at sea level.
- Boost Pressure: The positive pressure generated by a forced induction system (turbocharger or supercharger) relative to the current atmospheric pressure.
- Absolute Pressure (MAP): The total pressure within the manifold, calculated as the sum of atmospheric pressure and boost pressure.
Technical Considerations
When tuning or diagnosing forced induction systems, ensure that your sensor scaling and data logging configurations account for the difference between gauge pressure (boost) and absolute pressure (MAP).
Tip
Always verify your Manifold Absolute Pressure (MAP) sensor's range to ensure it can accurately read the maximum boost pressure levels intended for your specific setup.