This doesn't prove what you posted. It only proves what I already know. That oil type filters "may" let in dirt because they flow more air.

 

It certainly provides some powerful evidence. The data and charts are there, if you know how to digest them. Paricularly interesting is the graph near the bottom of the page, second from the bottom.

 

I love lamp.

 

"May" let in dirt??
About 17 times as much dirt as the AC brand paper filter.

 

This is a very interesting thread, any more articles/data/information on paper filters vs oiled? Or do you know of just this one, which seems to about automotive filters (although it can translate to the bike world, but I don't know of any WIX or AC Delco air filters for bikes, and the AMSoil paper filter seems the worst of the bunch but they do make bike filters).
Any info on how do paper filters stand up when exposed to the elements (not necessarily rain which we know would trash a paper filter), as in an open high flow filter such as a Kuryakyn or Outlaw A/C. Also which ones do you recommend, and are there any longitudinal studies that show how they wear over time? I wonder if those test results change as the paper filters wears, especially when exposed.

 

Johnson Engine Technology. JET AirStack.

 

You've thrown a lot at me, but I'll answer as best I can.

I don't think the Amsoil filter is paper (cellulose). They describe it as a washable nanofiber material.

I run paper filters on my dragboat, and they handle occasional water spray just fine. They aren't exposed to heavy rain, or a pressure washer, so I can't comment on how they'd handle that.

K&N, and similar oiled-cotton-gauze type filters are probably available in the widest variety of interesting shapes and sizes, and can handle direct water application for sustained periods. That's why I use them on some things. Whatever their deficiencies, it's a whole lot better than nothing.

Understand though that with heavy water application, some of the dirt they are holding will get washed into the intake.

I have one more article on filter testing (much lower-tech than the first), but I haven't been able to find it yet. It had to do with testing filters using Miata as the test platform. Haven't come up with anything specifically for bikes, but as you essentially said, many things will cross over.

What do I do myself? I have one bike with a non-oiled washable Screaming Eagle filter kit, which eliminates the air box, and another with the factory filter and air box. If someone could demonstrate that I could make significantly more power with an oiled cotton gauze filter, even if it increased wear, I might be interested. The funny thing is that a tune is usually recommended when one switches to these filters. So what increased power? Was it the filter, or was it the tune?

 

Thanks for this. It has been an interesting project to research. I have been looking into this today and I have yet to find any studies on bikes, although there is some talk about this on some BMW bike forums.

I also have not been able to find any paper filters that would work "outside the air box", including Screaming Eagle filters. I am looking for a round filter that would fit in a variety of AC options, such as the E-series K & N filters. If it is out there, I have not found it yet, which leads me to believe that they while paper may work well "in the box", it may not work well "out of the box". You are right about the Amsol, they are a synthetic nanofiber, not paper or cotton. Either way they didn't do so well in the study you posted.

Most of my car buddies I spoke with today said that AC's had little to do with their car's performance, and that the stock AC's work well. To your point its more then just the AC, although the type of air going into your engine has a lot to do with longevity and wear. That's why I don't vent bad air back in to the heads, I don't know why HD ever designed it that way. I run a see through AC cover and after about 3 months of summer pollen and dust I had some visible particles on the inside of my AC. I would love to get a paper filter and do a comparison, noting performance and air quality, as best I can.

Thanks for interesting idea.

 

Emission compliance. But on a side note, many "kids today" complain about the stink of a crankcase which is vented to the atmosphere, and also the stink of a car without catalytic converters. I grew up being fine with all of that, not really even noticing it. But I'd still rather not have it today, unless it accomplished something impressive in the engine longevity or power realm.

 

Funny. Second to last chart say that the Paper filter holds up well in dust loading. But last chart shows that the oiled filter holds up better in flow?

It's common knoledge that an oiled filter will flow more air than a paper filter. It's common sense to because an oiled filter has bigger holes in it. The oiled filter relies on maintaining the oil barrier for propper filtration.