Fuel Injector Calculators
Version 0.3

Fuel Injector Size Calculator

Enter Engine Data
Engine Horse Power
BSFC
Number of Injectors
Max Duty Cycle
Fuel Pressure
Calculated Injector Flow Rate
lb/hr
cc/min
To use the Fuel Injector Size tool to select the correct size injector for your engine, fill out the above form with the specified data. Here are some hints -
  • Horsepower - Expected Horsepower of the engine build
  • BSFC - Naturally aspirated engine will have a BSFC in the range 0.50, or another words 0.50 lbs. of fuel per/hour for each horsepower it makes. Supercharged and Turbocharged engines will want to be at 0.60 lbs/per plus
  • Number of Injectors - Number of Injectors used (often 1 per cylinder, but not always true)
  • Max Duty Cycle - Injector Duty Cycle should normally not be over 80% (0.80)
  • Fuel Pressue - The fuel pressure in your rails. Commonly 43.5 psi
The output graph shows a range of injector sizes vs. horsepower, hit the 'Sample' button to give it a try.
Fuel Injector Horsepower Calculator
Injector Capacity
Injector Flow Rate
Number of Injectors
BSFC
Maximum Injector(s) Capacity
Horsepower Potential
To use the Fuel Injector Horsepower tool to select the correct size injector for your engine, fill out the above form with the specified data. Here are some hints -
  • Flow Rate - In Lbs/Hour or CC/Minute (use dropdown to choose measure)
  • Number of Injectors - Number of Injectors used (often 1 per cylinder, but not always true)
  • BSFC - Naturally aspirated engine will have a BSFC in the range 0.50, or another words 0.50 lbs. of fuel per/hour for each horsepower it makes. Supercharged and Turbocharged engines will want to be at 0.60 lbs/per plus
The output graph shows a range of injector flow vs. horsepower, hit the 'Sample' button to give it a try.
Fuel Pressure Change Calculator
Fuel Flow After Pressure Change
Old Pressure PSI
Old Flow
New Pressure PSI
New Injector Fuel Flow
New Flow lbs/hr cc/min
To use the Fuel Injector Horsepower tool to select the correct size injector for your engine, fill out the above form with the specified data. Here are some hints -
  • Old Pressure - Injectors Old Operating Pressure (PSI)
  • Old Flow Rate - In Lbs/Hour or CC/Minute (use dropdown to choose measure)
  • New Pressure - Injectors New Operating Pressure (PSI)
The output graph shows a range of fuel pressure vs. injector flow, hit the 'Sample' button to give it a try.
Injector Unit Conversions

Used to convert LBS/HR to CC/Min or the other way around. Use the drop down to select which way you want to go.