measuring kerfed and flared ports?

[bdog]

do i measure from the beginning of the port or just the straight section or what?

[Cadillac John]

Curious as well. I was thinking about using a string, start before where the kurf starts and going to the end of the slot, then measuring it on a ruler/tape measure.

[Jessica]

I know flared aero ports are half the radius + length roughtly, the formula is actually

Lv = ((8466.4R^2) / ((Vb)Fb^2)) - 1.463R

Lv=port length in inches

Vb=Volume of box in cuft

Fb=Tuning freq

R=Radius of port (1/2 port diamater)

Also Aero ports should be 1" longer than "Lv" when assembled.

For slot port boxes measure down the center of the port, and as for kerfs, i don't know if the kerf even counts as part of the port or not. Someone more experienced will have to chime in on that one.

edit

added a couple of parentheses to formula for clarification.

[Jessica]

Also there is this calculator.

http://www.psp-inc.com/tools.html

[RAM_Designs]

Use half of the kerfed section as port length.