Maxi Calculator

Boost Horsepower Calculator

Calculate power gains from turbocharger or supercharger boost pressure

Boost Horsepower Calculator

Enter the engine's base horsepower

Enter the boost pressure in PSI

Standard atmospheric pressure is 14.7 PSI at sea level

Typical range is 80-90% for most engines

Table of Contents
How Boost Pressure Works

Boost pressure increases engine power by forcing more air into the cylinders:

  • Forced Induction: Turbochargers or superchargers compress incoming air
  • Air Density: Compressed air contains more oxygen molecules
  • Fuel Mixture: More oxygen allows for more fuel to be burned
  • Power Output: More fuel burned results in increased power
Calculation Method

The calculator uses these key parameters:

  • Base Horsepower: Engine's naturally aspirated power
  • Boost Pressure: Additional pressure above atmospheric
  • Atmospheric Pressure: Standard air pressure (14.7 PSI at sea level)
  • Volumetric Efficiency: Engine's breathing efficiency

The formula considers the pressure ratio and volumetric efficiency to estimate power gains:

  • Pressure Ratio = (Boost + Atmospheric) / Atmospheric
  • Power Gain = Base HP × (Pressure Ratio - 1) × Volumetric Efficiency
Important Factors

Several factors affect boost pressure performance:

  • Intercooling: Cooling the compressed air for better density
  • Fuel System: Must supply enough fuel for the additional air
  • Engine Compression: Lower compression ratios handle boost better
  • Engine Components: Must be strong enough for increased pressure
  • Altitude: Affects atmospheric pressure and boost effectiveness
Tuning Tips
  • Start with conservative boost levels
  • Monitor air/fuel ratios carefully
  • Use high-octane fuel for boost applications
  • Install boost and fuel pressure gauges
  • Consider professional tuning for optimal results
Frequently Asked Questions

What is a safe boost level for my engine?

Safe boost levels depend on your engine's design and modifications. Stock engines typically handle 5-7 PSI, while built engines can handle more. Always consult with professionals for your specific setup.

Why is volumetric efficiency important?

Volumetric efficiency indicates how well your engine breathes. Higher efficiency means better power gains from boost. Most engines range from 80-90%, with performance engines reaching higher.

Do I need to upgrade my fuel system?

Yes, adding boost typically requires fuel system upgrades. More air means more fuel is needed. Upgrades often include larger injectors, higher-flow fuel pump, and proper fuel management.