Injector performance calculator

Injector performance calculation with the pressure increased

It’s not required to search for certain manufacturer in a brochure in order to find out how much engine power the injector engine is able to support — all calculations can be made while using the empirical formulas available in the article called «Injector Performance». It’s possible to use a special calculator in order to make calculations quickly as well as avoid delving into the formulas.

How to use the calculator

It is enough entering the engine power desired, operating injectors amount as well as determine fuel consumption loss factor (depending on the engine type being used) and make changes in fuel pressure, if any, since the standard pressure in the fuel rail is 3 bars. It is not recommended changing the injector load percentage, since the base value is optimal, and the operation quality will deteriorate if making any changes. Our calculator will quickly calculate the static injectors fuel performance required for your car's engine just by making one click after entering all the data.

The calculator can be used both while replacing regular injectors with another company’s analogue as well as during tuning or the usual fuel testing injectors at a special test bench.

Besides online calculation can be done while having the pressure increased. It can be raised up to 4.5 bars (for turbocharged tuning engines). It is enough adding the old capacity as well as fixing the pressure the fuel system will have to operate at in order to calculate the required static performance indicator value. Then, a new maximum injector throughput indicator will appear in the open state, determined by the gasoline amount per time unit (cc/min or cm³/min).

Note the injectors must be always selected with a performance margin. This principle will ensure enough fuel amount in all engine operating modes even if the fuel delivery system is clogged.


  • cc/min — what is it?

    If we take apart the designation cc/min in parts, «cc» is a unit of volume, and «min» respectively the time interval. All in place expresses the static capacity, which determines the amount of liquid (in this case fuel) flowing through the injector orifices per unit time (1 minute). Injector manufacturers also call such capacity «injector size» and indicate the value in cm3/min (cc/min).

  • How can I find out the injector output?

    Different manufacturers can code the performance of fuel injectors differently, some by color, and some by marking. But since there is no universal method of determining how much fuel they flow per minute, the best way to know the performance of injectors is to pour them on a special bench.
    The injector is connected to the fuel rail at 3 bar pressure, placed in a measuring bulb, powered and timed. According to the amount of fuel spilled, expressed in cubic centimeters, it will be possible to judge the performance. This method is used when checking the cleanliness of injectors from carbon deposits. Contamination of injectors leads to a decrease in their flow capacity. If there is no measuring flask, then, at a minimum, you need to know the weight of fuel spilled under pressure through the injector for one minute. To know the capacity in cubic centimeters you need to divide the weight by the density of the fuel (it will differ from the brand of gasoline), the average density is 0.76 g/cm³.

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