A
Anonymous
Guest
This is taken from the T04B Housing Help thread. I threadjacked and thought this topic could use it's own dicsussion, since it's pretty important to turbo selection.
(Copied from previous thread- Gassed 260 told me airflow rate of 347CFM at 15psi boost, 5000 RPM, and 80% Volumetric efficiency. I got different numbers and am looking to figure out why)
Hmmmnn.... I get 467.7 CFM. How are you arriving at that?
Here's what I did:
(cid*RPM*.5*Ve)/1728 for N/A flowrate. It comes to (200*5000*.5*.8)/1728 = 231.48 CFM
Pressure ratio = (Patm + Boost)/Patm = (14.7+15)/14.7= 2.02
N/A flowrate * Pressure ratio = Boost flowrate = 231.48 * 2.02 = 467.7 CFM.
Is ther a critical assumption I've missed someplace?
To avoid further thread-jacking, I'm going to start a new discussion topic on "airflow calcs under boost"
(end copy)
--mikey
(Copied from previous thread- Gassed 260 told me airflow rate of 347CFM at 15psi boost, 5000 RPM, and 80% Volumetric efficiency. I got different numbers and am looking to figure out why)
Hmmmnn.... I get 467.7 CFM. How are you arriving at that?
Here's what I did:
(cid*RPM*.5*Ve)/1728 for N/A flowrate. It comes to (200*5000*.5*.8)/1728 = 231.48 CFM
Pressure ratio = (Patm + Boost)/Patm = (14.7+15)/14.7= 2.02
N/A flowrate * Pressure ratio = Boost flowrate = 231.48 * 2.02 = 467.7 CFM.
Is ther a critical assumption I've missed someplace?
To avoid further thread-jacking, I'm going to start a new discussion topic on "airflow calcs under boost"
(end copy)
--mikey