• HP = Horse Power
• BSFC = Brake Specific Fuel Consumption
• Duty Cycle = amount of time that the fuel injectors are switched on

This is a handy calculator to determine reccomended fuel injector flow rates.
Remember that unless you have specific dyno numbers for HP and BSFC, this calculator will only produce estimates.

: Estimated Horse Power

1 2 4 5 6 8 10 12 16 : # of Injectors (Generally one per cylinder.)

.05 .10 .15 .20 .25 .30 .35 .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00 : BSFC (For normally aspirated engines 0.45-.50 is considered normal.)

.05 .10 .15 .20 .25 .30 .35 .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 1.00 : Injector Duty cycle (80% is considered the normal max without causing overheating of the injector.)

Calculated Injector Flow Rates:

Convert between lb/hr and cc/min.

Convert lb/hr to cc/min.
Convert cc/min to lb/hr.

: lb/hr

: cc/min

Determine change in injector flow rate when fuel pressure is changed.

: Beginning flow rate in lb/hr.

: Beginning Fuel Pressure in PSI (43.5 psi is generally considered industry standard.)

: New Fuel Pressure in PSI

Determine the maximum amount of horsepower a given injector flow rate can support at 80% duty cycle.

: Beginning flow rate in lb/hr.

1 2 4 5 6 8 10 12 16 : # of Injectors (Generally one per cylinder.)

.05 .10 .15 .20 .25 .30 .35 .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00 : BSFC (For normally aspirated engines 0.45-.50 is considered normal.)

: Horse Power