How Much Horsepower Will Your Fuel System Support?

HP*lb/hrThis is your Brake Specific Fuel Consumption. Choose between NA/Turbo and Piston/Rotary. Most turbo rotaries will use 0.62. You may also designate your own value.
Fuel Pressure:
psiThis is your base fuel pressure measured at the FPR or fuel rail. (No vacuum or boost)
Fuel Injectors:
Bank#cc/min lbs/hr

Input how many injectors you have, and how much fuel they flow at 43.5 psi (standard pressure) Enter values in cc/min or lbs/hr.

Max Duty Cycle:
%This is the maximum duty cycle that the injectors will see. The stock 3rd gen RX-7 ECU maxes out around 63%. The recommended maximum value for programmable ECU's is 85%. Anything above that can result in overheating and cause damage to the injector.
Drivetrain Losses:
%This is an approximation of the power lost in the transmission, differential, etc. Generally loss is between 15-20%
Flywheel HP:
HPWith the above components, your fuel system should be capable of providing enough fuel for this amount of flywheel HP. This is comparable to manufacturers' HP ratings.
Wheel HP:
WHPWith the above components, your fuel system should supply enough fuel for this amount of HP at the wheels. This is the power that is measured on a chassis dynamometer.

What Size Fuel Pump Do you require?

Boost Pressure:
psiFor normally-aspirated engines, enter zero. For turbocharged engines enter your max boost pressure
Fuel System Pressure Drop:
psiAll fuel systems will have a pressure drop from the pump to the rails, due to the lines, filter and other restrictive fuel system components. Enter this value here, if unknown use the default 15 psi.
Fuel Pump Requirements:
You need a pump that will flow:
L/hr at psi
Based on the above given parameters, you will need a fuel pump with these minimum requirements.


Special Thanks to Maxcooper for letting me use his Fuel calculator script