1. What is Boost PSI?

Boost PSI is the measure of pressure above atmospheric pressure in an engine's intake manifold. It represents the additional pressure created by forced induction systems like turbochargers or superchargers.

2. How Does the Calculator Work?

The calculator uses the simple boost formula:

Where:

• Manifold Pressure — Absolute pressure in the intake manifold (psi)
• Atmospheric Pressure — Normal air pressure at sea level (typically 14.7 psi)

Explanation: Boost pressure is the difference between the pressure inside the manifold and the outside atmospheric pressure.

3. Importance of Boost Calculation

Details: Accurate boost measurement is crucial for engine tuning, performance assessment, and preventing engine damage from excessive pressure.

4. Using the Calculator

Tips: Enter manifold pressure (absolute pressure reading from your boost gauge) and atmospheric pressure (14.7 psi at sea level). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between absolute and gauge pressure?
A: Absolute pressure includes atmospheric pressure (14.7 psi at sea level), while gauge pressure shows pressure above atmospheric.

Q2: What's a typical boost pressure for turbocharged engines?
A: Most production turbo engines run 6-15 psi, while performance builds may run 20-30+ psi.

Q3: Does atmospheric pressure change with altitude?
A: Yes, atmospheric pressure decreases with altitude (about 0.5 psi per 1000 feet elevation gain).

Q4: How is manifold pressure measured?
A: With a pressure sensor (MAP sensor) connected to the intake manifold after the throttle body.

Q5: What's considered high boost?
A: Generally anything above 15 psi is considered high boost, requiring engine modifications for reliability.