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Fuel density question lb/Hr cubic inch/hour

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Hi, when you say 60lb/Hr injector, does it mean that gasoline density has been taken in account?

Some injectors are rated in cc/min so it s a volume not a mass.

When converting from cc to lb, do i néed to use gasoline density?

I dont know if my question makes sensé though.

Thanks for the courses, easy to understand as english is not my 1st language.


Hey Arnaud,

The value supplied when buying injectors will either be the flow rate or mass of the injector and this will be at a certain temperature which should be specified by the supplier. For example Injector Dynamics use Iso-Octane at 52c. This means the fluid temperature has been taken into account when providing a flow/mass value. You can then use the equation to work out lb/hr to cc/min or other way around. If the injector was 60lb/hr it would be 60*10.5 = 630cc . Or if the injector was 750cc it would be 750/10.5 = 71lb/hr

Pump gas density does vary, although the value is not as large as you may think. From memory pump gas is around .745 g/cc at around 20c and has a variation of .00095 g/cc per 1c change.


So for converting from lb to volume we need to know what "lb" we are talking about right?. In this case its gasoline right?

So if the injector is a 60lb water for exemple the volume would be different than gasoline value.Am i right?


The equation for water is 7.56 and gasoline is 10.5

60lb/hr in gasoline is 630cc/min

60lb/hr in water is 450cc/min

Thanks Chris ! That makes sense now