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LS injector & fuel pump calculator
Injector size and fuel pump flow for your horsepower goal, fuel and boost.
How this is calculated
Formula: injector lb/hr = hp × BSFC ÷ (injectors × duty cycle). BSFC assumptions: gasoline 0.50 NA / 0.60 boosted; E85 0.70 NA / 0.80 boosted (E85 needs roughly 30–40% more fuel by mass). Pump flow = total fuel lb/hr ÷ fuel density (gasoline 6.07 lb/gal, E85 6.57 lb/gal) + 20% margin.
Chart value: interpolated from Speedway Motors' injector chart (3 bar base pressure, 85% max duty), which Speedway says runs 30–40% above typical calculators — treat it as the conservative end.
Pump row: the smallest pump class from Summit's free-flow table rated for your power (gasoline). Real flow drops as pressure rises: check the pump's curve at your fuel pressure.
See the fuel, E85 & injector guide.