You hit it right on the head,
MOST PEOPLE DON'T INSTALL THEM PROPERLY!
Its like 2 pages into the instructions that you need
to oil the K&N before installing it. I play at a race shop
and do a lot of weekend work wrenching on race cars,
I've literally installed a hundred of these in the last 10 years.
For a while the K&N's did come pre-oiled in a sealed bag in the
box and they dripped oil when you unpacked them. But the only
ones I saw like that were the round SBC style for stock air cleaners and
a few of the ones like fit the YJ air box.. But recently have all come almost dry.
I like the foam filters better cause they are easier to clean, but the Unitfilter style
are about double the price of a K&N and in road racing the dirt is not a big deal,
many guys run without filters at all especially on the really high winding Weber
side draft equipped engines. They just have a 1/4 in grid trash screen.
