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Discussion Starter #1
i am in the process of building a liquid intercooler and am curious if anyone knows how to get a cfm rating per diameter @ at specific pressure. any help will be greatly appreciated! thanks, ron.







<font size=-1>[ This Message was edited by: rj on 1/2/02 3:24am ]</font>
 

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I dont think this is what you want but....

I was trying to find out what throttle bodies gave a flow compared to a "known".
I used a 850 Holley as the start point.
There are probably some flaws in it.

I think plates etc are flow rated at 28"Hg but that may be 28"H2O (which is vastly different - XR9UTE may know when he reads this topic)

Anyway.. a Holley 850 has 1 9/16" venturi bores. Doing the maths converts this to 110.8 cfm per square inch of bore area.
(850cfm / (3.1415*(13/16"*13/16")*4)

I dont know if this is anything like what you want but it sounds good eh!
 

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Discussion Starter #3
thanks tony, that's similar to the formula that i had came up with. i was kinda looking for a mathematical formula per specific area ..but that type formula may have to do. thanks again, ron.
 

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Took me a while didn't it?
I don't know the formula you're after but apparently 1.5" Mercury(20.3" water) is the standard for 4 barrel carbs. Ive quizzed an engineer about this previously and he says you cannot convert directly as flow through an opening has as much to do with the shape as it does area. I have some flows of various aftermarket throttle bodies somewhere if that would help you? You probably have it sorted now anyway?

Cheers,
Pete.
 

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Rj,

This right out of the Machinery's Handbook 24th Edition, Page 2413

Flow of Air in Pipes-
v=Square root of 25,000*dp/L
v=velocity of air in feet per second
p=loss of pressure due to flow through the pipes in ounces
d=inside diameter of pipe in inches
L=length of pipe in feet

p=Lv,squared/25,000d
 
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