Fuel Pump Calculator

Adjust the calculator values below

Minimum pump flow at operating pressure 210.053 L/h
Minimum pump flow in GPH 55.49 US gal/h
Engine fuel demand 182.654 L/h
Estimated fuel mass flow 300 lb/h
Operating fuel pressure 58.5 psi
Fuel density preset 0.745 kg/L
Entered BSFC 0.6 lb/(hp·h)
Sizing margin added 27.398 L/h
Pump selection check Verify ≥210.053 L/h at 58.5 psi on the pump curve
210.053 L/h
Minimum pump flow at operating pressure Compare this flow with the pump manufacturer's curve at 58.5 psi and the actual supply voltage
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Fuel Pump Calculator

Use this fuel pump with target engine power, estimated bsfc, and fuel density preset to get fast results, understand the formula behind the...

Size flow from power, BSFC, and fuel density

Estimated fuel mass flow equals target horsepower multiplied by brake-specific fuel consumption (BSFC). The calculator converts that mass flow to volume using the selected fuel-density preset, then adds the sizing margin. Power entered in kilowatts is converted to mechanical horsepower before the BSFC calculation.

Check the required flow at maximum operating pressure

A boost-referenced regulator normally raises rail pressure one psi for each psi of boost, so maximum pump pressure is base pressure plus boost. A fixed-pressure setup uses base pressure only. Pump delivery falls as pressure rises, so compare the calculated flow requirement with the manufacturer's pressure-flow curve at the displayed operating pressure and actual electrical supply voltage.

Treat this as a sizing estimate, not a pump guarantee

BSFC and fuel density are assumptions, and real demand depends on tune, mixture, engine efficiency, fuel composition, temperature, restrictions, filters, wiring, voltage, controller behavior, and pump condition. This calculator does not interpolate a particular pump curve or verify injectors, lines, regulator, electrical load, compatibility, or installation safety. Confirm the complete fuel system with manufacturer data and a qualified engine professional.

Frequently asked questions

Common questions about BSFC, fuel density, required pump flow, boost-referenced pressure, pump curves, sizing margins, and system limitations.

How is the minimum fuel-pump flow calculated?

Target horsepower is multiplied by the entered BSFC to estimate fuel mass per hour. Fuel density converts mass to liters per hour, and the sizing margin is then added.

What is BSFC?

Brake-specific fuel consumption is the fuel mass an engine uses per horsepower-hour. It changes with the engine, tune, fuel, load, and operating point, so dyno or engine-builder data is preferable to a generic assumption.

Why does operating pressure matter?

An electric pump normally delivers less flow as pressure rises. The required flow must therefore be checked against the manufacturer's pump curve at the calculated maximum operating pressure, not against a free-flow or lower-pressure headline rating.

When is boost added to base fuel pressure?

Choose the 1:1 boost-referenced option when the regulator raises rail pressure one psi per psi of boost. Choose fixed rail pressure when maximum rail pressure remains at the entered base value.

Does the calculator derate a specific fuel pump?

No. It calculates the minimum required flow and the pressure at which that flow is needed. Pump curves vary by model, voltage, fuel, and test conditions, so the final comparison must use manufacturer data.

Is the sizing margin enough to guarantee the system?

No. The margin only increases the calculated demand. It does not verify injectors, filters, lines, regulator, wiring, voltage, controller, fuel compatibility, installation, or pump condition.