My thing against non-paper filters is based upon information I have seen in engineering testing, and from a few reliable Internet sites.
That, plus my own experience with a few other guys at a Dyno in Smyrna TN, and the dynos we ran with K&N filters and with stock Delco filters with Corvettes. We say NO increase in HP with K&N versus new paper filters from Delco.
I am talking about straight replacement filters, not ram air type systems with K&N filters, since we did not study these systems, and the addition of a cool air ram system to a Vette does add HP.
I do know that engineering test I have seen do show that foam, sponge, etc., type filters DO allow more dirt into the system. However, if they get wet, they filter better than a paper filter.
The debate on the differences in filters will go on for as long as there is an engine that requires filtered air. Similar to debates on Ford versus Chevy versus Dodge trucks.
Everyone will do what they want to do, and that is great, and one reason why forums like this are so much fun.
