INJECTOR AND ENGINE HP/KW CALCULATOR

Properly sizing your fuel injectors ensures that your engine receives the correct amount of fuel at maximum power while maintaining precise fuel control at idle and cruising speeds.

Using injectors that are too small can result in fuel starvation, leading to lean conditions and potential engine damage under load. On the other hand, injectors that are too large can make idle and cruise tuning difficult, leading to poor drivability.

This calculator helps you determine how much horsepower and kilowatts your injectors can support based on injector flow rate, BSFC (Brake Specific Fuel Consumption), and duty cycle.

Important Notes:

• Injector Flow Rate Selection: This calculator allows you to input flow rate in either CC/min (cubic centimeters per minute) or Lb/hr (pounds per hour). Be sure to select the correct unit from the dropdown.
• BSFC Value (Brake Specific Fuel Consumption): BSFC measures how efficiently an engine uses fuel to produce power. Use the table below the calculator to select the correct BSFC value based on your engine type and fuel. If unsure, use the higher value within the range to provide a slight safety margin.
• Max Duty Cycle %: Injectors should not operate at 100% duty cycle for extended periods, as this reduces reliability and limits fuel delivery control. A typical safe limit is 80% to 85%.
• Injector Fuel Pressure: The horsepower estimate assumes that the injectors are operating at their rated flow pressure. Example: If an injector is rated at 550cc at 4Bar, then running it at 4Bar fuel pressure will produce that exact flow rate. Running at a lower or higher pressure will affect flow.

How to Use This Calculator:

• Enter your injector flow rate in CC/min or Lb/hr.
• Select the BSFC value based on your fuel type and engine setup.
• Set the max duty cycle, typically between 80% and 85%.
• Enter the number of injectors in your engine.
• Click "Calculate HP & KW" to see:
  • Horsepower per injector
  • Kilowatts per injector
  • Total estimated engine horsepower
  • Total estimated engine kilowatts

This tool provides an accurate injector power rating, helping you make informed decisions when selecting injectors for your setup.