Fuel Injector Size Calculator

Estimate the injector flow rate needed for your engine.

Desired Flywheel Horsepower

Number of Cylinders

Aspiration

Fuel Type

B.S.F.C.

Max Duty Cycle (%)

Expected Fuel Pressure (psi)

BSFC: fuel used per horsepower-hour, typically 0.48–0.80.

Maximum injector duty cycle, typically 80% for safe operation.

This calculator is a reference tool only. Real-world injector sizing may vary based on tuning, fuel pressure, and other factors.

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