I bought one of the Amsoil drop-ins about 2 months ago (almost 10k now)... here are my unscientific findings:
I put this thing into a housing that I had drilled to resemble swiss cheese. The filter had some dirt on it's face, but not that bad. I took a clean, white paper towel and wiped the inside (motor side) of the intake and not even a hint of dirt. The only downside was that I added oil to the filter and you could see it tracking along the inside of the intake tube... only a couple inches... and that is most likely from me over oiling the already preoiled filter.
I can live with this as the filter has seen everything from very dusty conditions to very wet conditions. As a side note for comparison, the K&N I had on my 99 CTD would allow VISIBLE dirt into the engine side of the intake... needless to say, I wasn't going that route again and I am very pleased with the results the Amsoil filter is giving.
I know about the "air filter testing" site that shows all the different filters, and the Amsoil rated average, but in real world testing, it seems to work very well.
steved
I put this thing into a housing that I had drilled to resemble swiss cheese. The filter had some dirt on it's face, but not that bad. I took a clean, white paper towel and wiped the inside (motor side) of the intake and not even a hint of dirt. The only downside was that I added oil to the filter and you could see it tracking along the inside of the intake tube... only a couple inches... and that is most likely from me over oiling the already preoiled filter.
I can live with this as the filter has seen everything from very dusty conditions to very wet conditions. As a side note for comparison, the K&N I had on my 99 CTD would allow VISIBLE dirt into the engine side of the intake... needless to say, I wasn't going that route again and I am very pleased with the results the Amsoil filter is giving.
I know about the "air filter testing" site that shows all the different filters, and the Amsoil rated average, but in real world testing, it seems to work very well.
steved