air flow #s ?

Kevin Panzino · 07-17-2013, 11:47 PM

Quote:

Originally Posted by rod

great discussion. let me throw this ? out. if you had a port flowed at 25" and let's say it flowed X.CFM, then changed to 28" [all else remaining equal] and checked the port, would it flow more or less?
thanks Rod in AZ

Sure, it would flow more, and to be precise, it would flow the square root of (28/25) times the original X cfm..

And that right there is what started this thread off in the first place !

The square law of compressible airflow !!!

Kevin

Adger Smith · 07-18-2013, 12:04 AM

Kevin,
Using math to extrapolate from 25 to 28 is correct. The laws of Physics allow us to do that, but you assumed there was nothing wrong (called a Problem) with the port that the increase in air speed didn't magnify or make show up.
There, that is the Real World problem with extrapolation and with assumptions.
As I've said or aluded to.... That is one of the reasons why there is a lot of salesmanship in below 28 numbers. There is no way in He** I would buy a head that was flowed @ 10 or 25 or anywhere in between and the numbers extropolated up to another flow number. That is IF I was buying based solely on flow numbers (which I wouldn't do, not a good idea!)

Dwight Southerland · 07-18-2013, 09:35 AM

It's kind of like using barometric pressure, humidity and temperature to predict ET without taking into account oxygen content in the air.

SSDiv6 · 07-18-2013, 11:49 AM

Quote:

Originally Posted by dwight southerland

it's kind of like using barometric pressure, humidity and temperature to predict et without taking into account oxygen content in the air.

x10!!!

07-18-2013, 12:04 AM	#2
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: air flow #s ? Kevin, Using math to extrapolate from 25 to 28 is correct. The laws of Physics allow us to do that, but you assumed there was nothing wrong (called a Problem) with the port that the increase in air speed didn't magnify or make show up. There, that is the Real World problem with extrapolation and with assumptions. As I've said or aluded to.... That is one of the reasons why there is a lot of salesmanship in below 28 numbers. There is no way in He** I would buy a head that was flowed @ 10 or 25 or anywhere in between and the numbers extropolated up to another flow number. That is IF I was buying based solely on flow numbers (which I wouldn't do, not a good idea!) __________________ Adger Smith (Former SS) Last edited by Adger Smith; 07-18-2013 at 12:12 AM.

07-18-2013, 09:35 AM	#3
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,001 Likes: 64 Liked 780 Times in 194 Posts	Re: air flow #s ? It's kind of like using barometric pressure, humidity and temperature to predict ET without taking into account oxygen content in the air.