Originally Posted By: oldhp
To me.
Hi-performance or drag car = K&N type oiled gauze filter.
Every day cars/trucks = OEM or OEM replacement filter, i.e., Wix, Fram, Purolator etc.
+1
I've run K&N on a car I sold to a friend at 152K, he sold it at 177K - the engine did not grenade. On a motorcycle I've run one for over 15 years - the engine did not grenade. I have zero doubt that a K&N causes increased wear vs. a better filtering air filter. The trade-off is simple: the potential for quicker RPM spin-up/increased HP in some cases in exchange for reduced fine particle filtering. If the stock set-up provides a restriction to air flow the K&N will generally help ET but if the stock set-up does not provide an air flow restriction the K&N generally won't do anything but pass more dirt into the engine. Currently I don't consider either of my passenger cars to be high performance or to have restrictive air cleaner/filter assemblies so I don't run a K&N in either but I still run a K&N in two of my three bikes strictly for the slight performance advantage and knowing full well that they don't filter as well as a "normal" filter. Decide which is more important: potential flow or filtering ability and buy accordingly.