Quote:

If people want to use the K&N formula - then this s how u calculate the surface area of a round filter.

Its circumference x height - Plug in the diameter into this calculator and itll tell you the circ.

Then x by height -

http://www.csgnetwork.com/circle_sphere_area_calculator.html


David Vizard says you need to adjust the height of the filter to account for the top & bottom molding and edge effects. So, your 3" filter calc really should be more like 2-3/4" (or whatever a particular filter measures) when you're trying to come up w/ effective surface area.

Also, for those who question the data I found and posted from tests performed elsewhere, no problem. But if you feel the need to pi$$ on the results, you should probably dig up your own data or -- even better -- conduct your own tests to (in)validate it.

At least I took the time to try and find something more than just a bunch of opinions on the subject.