Fuel Injector Max Capacity Calculator Injector flow rate: lb/hr Number of injectors: BSFC: Fuel Injector Max HP*: *NOTE: This formula calculates the maximum horsepower that fuel injectors in proper working order can produce. This formula WILL NOT be accurate if the fuel injectors in question are damaged, clogged, or modified. This formula will also be inaccurate if the rest of the fuel system cannot produce enough pressure and volume to supply the injectors. All calculations should be made at 43.5 PSI unless otherwise noted.