Quote Originally Posted by Gunfun View Post
I've always imagined that for sub 12 ft/lb there must be a maths formula you could use to determine the perfect diameter and length of port if you know how much pressure the compression tube is creating, is this flow rate calculator of any use ?

https://www.copely.com/tools/flow-rate-calculator/
I have three formulae for transfer port diameter, and they never agree with each other

There's too many unknowns to make such calculations reliable.

The flow rate calculator in the link is for fluids, not air.