That is an interesting write up in Hemmings, Patrick.
MikeB, do you have a source of that graph?� The K&N and the AFE filters are very similar yet seem to vary considerably in performance.� I have a K&N in my Passat, and AFE in my Tacoma, and now an Airaid in my Willys.� I couldn't find performance data on the Airaid website so sent them an email requesting such.� Maybe I'll hear back, maybe I won't.� Will post performance data if I can find it!� It seems like there would be a lot of filter performance data out there, but I'm watching football today!
Sorry been busy, the original article came from consumer reports and was reposted in a diesel performance magazine, it is about ten years old.
On modern cars with the tighter tolerances they are more susceptible to damage from �dusting� which is allowing fine particulate into the engine. And I have a more modern motor in my Willys (only 29 years old, compared to the 60 year old originals)�
something I forgot to take into account when I posted my response. The K&N style filter should do no more harm than a stock oil bath, as long as you don�t use a cheap knock off with a substandard filter media. When you think about it the original motors were built to be used in the worst possible environment with minimal maintenance.
I would still be very interested to see the oil analysis of a stock air filter set up us an K&N style.