Originally Posted by westxsrt10
Most high quality paper filters have TWICE the surface area of a cheaper K&N. More surface area allows more air flow. I have used oiled filters, the quailty varies greatly. The Airaid oiled filter is my choice, is twice as thick as most others.
Most Diesel engine warrentys will be voided using a K&N.
#1 Surface area is one factor, but more surface area does not necessarily guarantee more flow.
#2 Are you comparing all oiled filters in your statement? Yes, a cheap Pep Boys gauze compared to a two stage foam by a quality company will definitely vary greatly
#3 That is simply untrue about diesels and K&N. If I cared to spend the time, I could get you pictures of various aftermarket filters (mainly K&N) sitting on the shelf at your local Ford, Chevy and Dodge dealership that they will gladly sell you for your diesel.
In fact, a free flowing intake makes MUCH more difference on a turbo diesel than it does on a naturally aspired gas engine.