I did a search for "air filter", but oddly enough just came up with a bunch of oil filter threads and an argument about a FRAM cabin filter.

My wife's truck is due to for an air filter, and in most of my vehicles I just get a K & N. My justification is that it pays for itself being that is a one time purchase and will get .00000001 more HP.

As its been a while since I've had the pleasure of buying an air filter, I thought I'd ask the all knowing forum if there is a better choice out there these days.

And since apparently FRAM is crap - what cabin filter do people actually like?

I saw that thread... There’s nothing wrong with Fram. The internet is a wealth of information. However, most of that is baseless opinion.

I’ve used K&N’s for years. but, When I replace mine it’ll be one of the “dry” washable filters or stay with OEM.

Automotive air filter test — Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Automotive Repair Tips and How-To asks the question, "Are Amateur Air Filter Tests Accurate?" The article describes shortcomings in almost every air filter test found on the internet.

Best Car Air Filters Compared - Keep Your Engine Breathing Free With These Picks is nothing more than click bait to make money for the "reviewer".

The initial cost of a high performance filter, the on-going cost of cleaning solutions, the effort spent cleaning, oiling and whatnot isn't worth my time. A freshly cleaned high performance filter opens up lots of pores that have to be closed by larger dirt particles in order to improve filtering efficiency.

I've used Fram cabin filters for years and they're fine. For a drop in filter I always use K&N and have always been happy with them

You might check out the AFE drop in filters. If you are not doing a lot of dusty road driving the dry 5R is super easy to take care of. There have been a lot of tests covering oiled filters, and unless you really take care of them they can reduce performance. Anyway, google should pull them up.

I run dry in two other cars that don’t see much if any dust and dry filters are super easy to care for and allow much better flow than stock or an oiled filter.

Just pull it out, spray it down with 409, Simply Green, etc. let it sit 30-60 mins and rinse it off with warm water until the water runs clean. Let it dry overnight and install. Cheap and easy. If you don’t drive in a lot of dust you really can get away with only doing this once or twice depending on dust. My sports car really only “needs” it once a year (no dust and low miles)

I am running their intake with the 7 ply oiled in summer due to dust, but will be buying the 5R dry for winter use.

Either way maintenance is not a big deal.
Highway driving with oiled filter 30-50k between cleaning and oiling
Super dusty conditions 9k between cleaning and oiling.

Dry is so easy I just do it even when they don’t look dirty once a year while I am changing oil.

I had a K&N when I was going on dirt roads more often. I could clean it after a trip but it was a hassle and I got tired of the mess. Went to a Toyota OEM. Looks good and has a pre filter pad in front of the pleated section.

Yeah, me too. Cleaning, re-oiling, waiting for it to dry is a pain. OEM is inexpensive. If you’re driving in dust a lot just change it more frequently.

I use OEM filters as they are not so expensive. I had K&N before and wasn't really impressed

I have no science behind my opinion, but those "high-flow" engine air filters have me skeptical about the actual filtering properties of the filter. The trails out here in California are really dusty and silty. After every trip or trail run I check the engine air filter when I get home and there is a good amount of dust at the bottom of the airbox and at the bottom of the OEM filter w/ filter pad. On top of the filter and the intake its relatively clean. My fear stems with the higher flow filters and the amount of fine particles allowed through to provide the higher cfm.

For this reason I use the OEM with filter pad only. In my past research, I have seen part numbers without the prefilter pad.

There's really no benefit on a stock engine.

It seems like we're talking about both the air filter and the cabin air filter... right?
My personal experience is that I prefer just a stock air cleaner, and I'll change it more often if I need to. I tried a K&N in my F150 and it didn't do anything for me. Just my two cents...
And the cabin air filter... buy what you want, but make sure to get the one with the charcoal filter as part of it. That helps with smells in your ride.
I change both of mine yearly, unless I know I've been in some real dirty air.

I use this cabin air filter. From Amazon.
EPAuto CP285 (CF10285) Toyota/Lexus/Scion/Subaru Premium Cabin Air Filter includes Activated Carbon

The AFE type filters do not filter as well as paper ones. A lot more fine particulate goes through them. Does that matter? I really don't know without testing for long periods of time. Presumably most of the particulate goes out the exhaust, but some will either wear on the cylinders or end up in the engine oil. The link is a test that shows that the paper filter is 99.9% efficient while the AFE is only 86%. The AFE has about 50% less restriction. But it allows 330 times as much dust to pass.

http://shopping.na3.netsuite.com/c.1...y_75-80882.pdf

I finally bought a K&N for my WRX after watching this review/test.

YouTube


Jason does more empirical and interesting tests than most other youtubers given his engineering background. He also did a recent one on oil catch cans that has me thinking I will go ahead and install the cheap ebay one I bought a while back on my WRX since it is direct injection.

YouTube

I should know this, but is the 4Runner port or direct injection?

Port only. It would make better power and get better fuel economy if it had Toyota's D4S port and direct injection.