Converting Injector Flow Rates

[ms3blackmica]

I made this sheet a while back for some friends who did not understand the difference between mass flow rates and volume flow rates. I understand that the ms3/ms6 does not currently have an upgraded injector option, this can still be useful for anyone adding additional injectors to meet fuel demands. Or for anyone with other vehicles and need to understand the differences. Typically injectors are rated in either lbm/hr (pound mass per hour) or cc/min (cubic centimeter per minute).

These flow rates are rated at a given fuel pressure that they are tested at. Most people just use a conversion of ~10.5. That is fine. This is just to show the derivation and provide an understanding. I may have made it a little more complicated by switching from metric to USCS but the concept remains the same.

Converting lbm/hr to cc/min






Converting lbm/hr to cc/min

[TWOptSL0W]

Pound is not a unit of mass dammit very nice write up though

[silvapain]

Originally Posted by TWOptSL0W Pound is not a unit of mass dammit very nice write up though

Sure it is.

Pound (mass) - Wikipedia, the free encyclopedia

P.S. Why didn't you just put the formula into Excel OP? Way fucking easier.

[ms3blackmica]

Originally Posted by TWOptSL0W Pound is not a unit of mass dammit very nice write up though

it should of been lbm (pound mass).

oops!

Originally Posted by silvapain Sure it is. Pound (mass) - Wikipedia, the free encyclopedia P.S. Why didn't you just put the formula into Excel OP? Way fucking easier.

wanted to show the derivation on how its calculated.

[anavrinIV]

that brings me back to fluid dynamics....good times.

[TWOptSL0W]

Nope sorry it's fucking wrong. A pound is a unit of force actually. It is the gravitational force on an object due to its mass. More mass, more force (weight). Your mass is how much matter you have, i.e. how much "stuff" there actually is. If you go to the moon, you will have the same mass because you are still the same amount of person, but you will weigh less in pounds because the gravitational force is less on the moon, therefore, less force pulling your mass down.

Weight=mass*coefficient of gravity (on earth, it is 9.8 m/s^2) and your mass would be in kg which would give your weight in newtons actually.



Edit: ok now that we're talking about lbm it's all good carry on

[silvapain]

When injectors are rated in mass flow, the 'lb/hr' rating is actually 'lbm/hr'.

[ms3blackmica]

Originally Posted by TWOptSL0W Nope sorry it's fucking wrong. A pound is a unit of force actually. It is the gravitational force on an object due to its mass. More mass, more force (weight). Your mass is how much matter you have, i.e. how much "stuff" there actually is. If you go to the moon, you will have the same mass because you are still the same amount of person, but you will weigh less in pounds because the gravitational force is less on the moon, therefore, less force pulling your mass down. Weight=mass*coefficient of gravity (on earth, it is 9.8 m/s^2) and your mass would be in kg which would give your weight in newtons actually. Edit: ok now that we're talking about lbm it's all good carry on

mike you are absolutely correct. when i made this little sheet, it was for my "not so knowledgable" friends lol if i would of started explained lbm and lbf they would of been mind blown

Originally Posted by silvapain When injectors are rated in mass flow, the 'lb/hr' rating is actually 'lbm/hr'.

yes this is correct.