Port Area

What is the approximate port area of 4 4in aeroports ? Im building a new enclosure thats 6.5 cu ft with 4 4in aeroports 10in long.

4 4in round ports is like 50 sq in or so but the aero flare will make it a little more....Im thinking 75 sq in or so.

bret.. you really think the flares add 25 inches of port area?? the tube inside is still the same size ..12sq inches the flair makes a touch difference on tunning length i cant see the flair adding another 50% of port area. id just assume it to be 48-50sq inches of port and run with it .

4-4inch aeros is roughly 52 sq inchs of port. So as said go with that and get somthing built!!

Thank you for the quick replys, you guys are always very helpful

area of a circle is one half of pi(radius squared)


6.28318531 square inches per 4 inch port.

nosir... 12.56 = 2 x 2 x 3.14

Alan I was guessing but im like you I would say its 50 sq in of port and roll with it LOL

Alan wrote:

nosir... 12.56 = 2 x 2 x 3.14

i stand corrected. 12.56 is the actual area. you see i was calculating for the pretend area.

you guys are so smart all of you get smiley faces an a gold star by your names.

look up flare-it,for a calculator

Your formula for finding the area of a port (round port) is Pi * R^2 where Pi is 3.14 and R = radius. So, if you have a 4" port, it would be 3.14 * (2 * 2) as the radius of a 4" circle is 2". This yields 12.56. You can the multiply that by 4 for the total area of the ports, 4 * 12.56 = 50.24 sq in.

Now, you are using flared ports. To my knowledge there is no REAL way to find the exact port area, but a formula I use with fairly good success is Max (Pi R^2) + Min (Pi R^2) / 2. The breakdown is this: you take the maximum radius of the port, and the minimum radius of the port, and average the results. See below for a standard 4" flared port.

Minimum = 4" (the inner tubes dimension)
Maximum = 5.5" (the point where the flare begins it's inward curve)

Now, radius is 1/2 your diameter, so 4" = 2" and 5.5" = 2.75"

We plug these into Pi * R^2 and get:
4" ---- 3.14 * 2^2 = 12.56 * 4 = 50.24 sq in.
5.5" ---- 3.14 * 2.75^2 = 23.75 * 4 = 95 sq in.

If anyone else has a correction for me, please let me know.