Mechaniac
If your theory on this is correct, then you have to feel sorry for all those poor saps that spent $70 or more for a K&N filter. All that they really have is a modern day oil bath. They just have to be cleaned and reoiled more often because there isn't a reservoir of oil at the bottom.
The new Hot Rod (June '02) has a very interesting article on air cleaner filters. They compared 4 so-called high performance $40-$70 filters against a $5.99 Purolator. On 250 rear wheel HP the Purolator only gave up 5hp to the best. In their attempt at measuring actual air flow they were only able to guess that it gave up about 10%. They admittedly didn't have the right eguipment for that and only approximated. Also, they made no attempt at repeating the test with dirty filters.
