Electronic Fuel Injectors
AIR & FUEL / CALCULATOR
EFI injector &
fuel pump calculator.
Size your EFI injectors and fuel pump capacity based on target power, fuel type, BSFC and operating pressure.
01 /
Engine & fuel
%
85% is a common EFI injector sizing target.
lb / hp / h. The default updates automatically
according to fuel and induction type.
kg/l
Editable for specific race fuels or known fuel blends.
02 /
Injectors & fuel pressure
cc/min
PSI
Differential pressure used for the manufacturer's
injector flow rating.
PSI
With a 1:1 boost-referenced system, this differential
pressure remains constant under boost.
PSI
Used to calculate fuel pump operating pressure.
03 /
Fuel pump
%
Added on top of the calculated maximum engine fuel demand.
How does the calculation work? + −
Required injector fuel mass flow is based on target power and BSFC. Injector quantity and selected maximum duty cycle are then used to calculate the required flow per injector.
Injector flow =
(power × BSFC) /
(number of injectors × duty cycle)
Injector flow changes according to the square root of the fuel pressure ratio. The cc/min conversion also uses the selected fuel density.
New flow =
rated flow × √(new ΔP / rated ΔP)
For forced-induction engines, fuel pump operating pressure is calculated assuming a 1:1 boost-referenced fuel pressure regulator. Injector differential pressure therefore remains constant while total pump outlet pressure increases with boost.
Always check the fuel pump manufacturer's flow chart at the operating pressure shown by the calculator and at the vehicle's actual operating voltage. Free-flow pump ratings are not suitable for sizing an EFI fuel system.
Bombas de combustible