Hey Guys and Gals,

I am wondering if anyone could help me, it is just for curiosity sakes. I am trying to find out what these superchargers(centrifugal, rotor, screw) flow approx. such as CFM (cubic feet p/minute) at a given boost level. I know each supercharger would be different due to the impeller/rotor design ,speed, and other variables. If someone could help me with the info/formula and/or a link, I would greatly appreciate it.


Steven

 

Blowers do not produce boost. Blowers produce flow. Boost is created when there is a restriction after the blower (engine). A blower vented to atmosphere will move air but not create any pressure. A given blower hooked to 97 4.6 with pre pi heads may produce 6 psi boost. If you swap to the better heads the engine will make slightly more power but may only show 5 psi if nothing else changes becuse overall there is less restriction after the blower and the blower is still moving the same amount of air.

Air flow rate for normally asperated 5.0=
(cid x rpm x volumetric efficiency)/1728
(302 x 5500 x .85)/ 1728 = 408 cfm

.85 represents 85% which is a typical VE for production NA vehicles

Boosted air flow for the same example at 12 psi
pressure ratio x basic engine cfm
1.82 x 408 = 743 cfm

pressure ratio = (14.7 + Boost)/14.7

 

yeah...what he said