Quote:
Originally posted by sitinduk
Some questions about finding volume (cfm) and mass (lb/min) of airflow:
To account for volumetric efficiency of the engine multiply by formula by the percentage:
cfm = (cid * rpm * VE%) / (1728 * 2)
What is the VE of the D17, is it 90%?
Where does the 29 come from? The units for constant R are:
(cfm * psia) / (lb * mole * deg. Rankine), right? |
You can only assume that the VE is 90%, but it would be a good assumption I would assume, how about you? :P It's higher on a FI engine though... so you can say 93-95. You could factor a ton of things into the equation for CFM though. If anybody is using VE, remember to use the decimal percentage. IE 90% = 0.90
The units for R is Cubic Feet... not CFM. If it were CFM, then using the equation wouldn't give you a flow value.
It's not really 29, it's 28.4 It's the standard pressure used on compressor maps for the ratio in airflow. 28.4inHg. Give me a break, it was late
Anyway, maybe I'll go make some corrections. The general idea of this all applies to all compressor maps, but this specific way applies to Turbonetics. Different companies use different units and standards.
