Fuel pump options

[oldeskewltoy]

When I was working selling Walbro fuel pumps and someone asked how to size a fuel pump, the Walbro engineers approved the following....

things you need to know....
peak volume of injectors
peak effective duty cycle of injectors
# of injectors




Count all the injectors and the volumes of each. Add up the total CCs of all injectors, then multiply that by whatever your maximum duty cycle is(usually 80%). Ok, now multiply that number you have by .015873, that will give you what your gph for all your fueling sources use(maximum fuel use at WOT). Now, since fuel running through a fuel system can get heated, add 20% to the total number you have. That is the maximum amount of fuel your vehicle will need(with those injectors at that pressure and at the duty cycle and with enough margin for error[or heating]) Any more can add heating to the fuel, or in worst case scenario, can "push" excess fuel past the injectors cause a low rpm rich condition.