You forgot one LITTLE detail in your calculation for 1145 cfm....
we are talking about a 4 stroke motor here... cut that in half... only half
of the displacement is moved in 1 rotation... the other rotation is used to
compress & get POWER!
so we're talking ~572 cfm, according to my calculations, and that assumes
100% VE (volumetric efficiency) which is a BIG assumption, but something to
shoot for...
Gary Shook
-----Original Message-----
From: Shaun.Hendricks@bergenbrunswig.com
<Shaun.Hendricks@bergenbrunswig.com>
To: dakota-truck@buffnet.net <dakota-truck@buffnet.net>
Date: Thursday, October 29, 1998 12:03 PM
Subject: DML: RE:TBI's & CFM's
> Well, maybe if you could take an empirical measurement somehow. You
might
>be calculating till the cows come home if you try and get an exact
>mathematical formula. If you could hook up some kind of graduated (non
>resistive) piston to the intake side of the cylinder (outside of the head)
and
>rotate the crank 1 time to see how much air it sucked in, I suppose that
would
>at least put you in the ballpark. It'd be basic math beyond that...
>
>Shaun H.
>
>---original message---
>Shaun,
>Excellent thought and a rightous one at that! If a 360 Cu in motor was a
>360 cu in air pump, @ 5500 rpm it would "push" 1145 cfm. This isnt the
case
>for an engine, but with some massive assumptions you can make an argument
>for 900-950 CFM air requirement @ Standard temp and pressure for a highly
>modified engine. The maximum "air" is based on the ignition timing, cam
>profile, compression ratio, head port configuration etc. and is not an easy
>theoretical # to come up with. Hense the "experimental method". (the 380
>HP crate motor (360 cu in) is dynoed with a 750cfm Holly carb or so I
>think..)
>BKB
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