Fuel Pump Calculator
Determine the correct fuel pump size for your engine. Ensure your vehicle gets the right fuel flow for optimal performance and efficiency.
Fuel Flow Estimator
How to Use Fuel Pump Calculator
Follow these simple steps to use a fuel pump calculator effectively:
- Enter Engine Horsepower: Input your engine’s total horsepower (HP).
- Select Fuel Type: Choose from gasoline, diesel, or ethanol-based fuel which determines the fuel density.
- Input BSFC Value: Use Brake Specific Fuel Consumption. Typical values are 0.45–0.55 for naturally aspirated gasoline engines, and 0.55–0.65 for turbo charged engines.
- Add Duty Cycle: Enter injector duty cycle (usually 80% or 0.8 is recommended).
- Calculate Fuel Flow: The calculator will show required fuel flow in Liters per hour (LPH) and Gallons per hour (GPH).
- Choose Fuel Pump: Select a pump that meets or exceeds the calculated flow for safety.
How to Calculate Fuel Pump Size - Calculation Guide
Use this general formula to calculate fuel pump size:
For gasoline, the Fuel Density ≈ 6.2 lb/gallon.
Example Calculation:
Given:
Horsepower = 400 HP
BSFC = 0.50
Fuel Density = 6.2 (Gasoline)
Step 1: Multiply HP by BSFC
400 × 0.50 = 200
Step 2: Divide by fuel density to get GPH
200 ÷ 6.2 = 32.25 GPH
Step 3: Convert to LPH
32.25 × 3.785 = 122 LPH
Final Answer:
Required fuel pump = Minimum 125 LPH.
Tip: Always choose a pump with 10–20% extra capacity for safety. By selecting an 80% duty cycle, the required capacity inherently has a built-in safety buffer margin.
Fuel Pump Conversion Chart
Note: Values are approximate for gasoline engines with BSFC = 0.50 and run at 100% duty cycle.
| Horsepower (HP) | Fuel Flow (GPH) | Fuel Flow (LPH) |
|---|---|---|
| 150 HP | 12 GPH | 45 LPH |
| 250 HP | 20 GPH | 76 LPH |
| 350 HP | 28 GPH | 106 LPH |
| 450 HP | 36 GPH | 136 LPH |
| 550 HP | 44 GPH | 166 LPH |
| 650 HP | 52 GPH | 197 LPH |
FAQs SECTION
A fuel pump calculator estimates the fuel flow required for your engine based on horsepower and fuel type.
Proper sizing ensures your engine receives enough fuel for performance and prevents engine damage.
A small pump causes fuel starvation, power loss, and possible engine failure.
Yes, but use a different BSFC value, typically higher than gasoline, and adjust for the heavier fuel density.
BSFC (Brake Specific Fuel Consumption) measures fuel efficiency of an engine. It indicates how much fuel is required to produce one horsepower for an hour.
Yes, choose a pump with 10–20% extra capacity for safe operation.
Multiply GPH by 3.785 to get Liters Per Hour (LPH).
Yes, turbo engines require more fuel to manage heat and power, so use a higher BSFC value.
80% is standard for safe and efficient operation without overheating the injectors.
Not directly, but improper pressure regulation can cause issues if the return lines or regulator can't handle the extra flow.