Does anyone have personal experience of a performance difference (i.e. increase) with different air filters? My skywagon came with a brackett (foam) filter already installed and I have just been changing those every year or so. I just came across Challenger's (K&N's) website http://challengeraviation.com/ and some of the customer comments make some pretty wild claims like picking up an inch or two of manifold pressure at altitude. Then I looked at Donaldson's website http://www.donaldson.com/en/aircraft/ga/ which claims that their filters actually flow better than either K&N or Brackett. If I could really pick up an inch or two of manifold pressure.... the price of a new filter would be worth it. Does anyone believe the hype or is this just typical marketing?

Just remove the air filter. That would show you if you're losing performance due to air filter restrictions, and if so, what the maximum possible gain would be.

Don't do this if you live in Iceland.

Paper air filters filter the best, but the flow falls off due to the filter being clogged up (bad in the rain at times as well.) Foam is the most common, but does not remove as much of the small stuff. K&N is a brand name for cloth oil filters. These flow more over time (less than a new paper filter), but at a cost...they don't catch as much of the fine stuff, and cost more. Two inches??? Total crap, no way, no how. Prove it in the test cell, I'll show up to see that!

K&N is one of the worst filtering filters on the market. They are probably fine if you never land in the dirt, but you'll never see one on anything that I own.

I have always had good results with K&N on my offroad vehicles, but it looks like that may not be the case for everybody. Hafast what kind of problem did you run into?

I agree with Hafast...wouldn't put one on anything I own..if you want more air, use a BIGGER filter for better flow..remember dirt tears up piston rings..the object of an air filter is to keep the dirt out of the engine. When I look at the cross section of a K&N fliter on a deep breathing engine I just think how STUPID!
My 2 bits.
HC

Air filters are what I do for a living. The simplest thing to do is hold one up to the light and see all of the holes in the media. Holes = dirt.

Hafast wrote:Air filters are what I do for a living. The simplest thing to do is hold one up to the light and see all of the holes in the media. Holes = dirt.

What plane do you fly and what filter do you use? What is your recomendation for a 182?

Tim

I had a K&N in a Suburban with a 454. It and the Flowmaster made quite a difference but I only got 102K out of the engine. Might have had something to do with pulling a backhoe around with it.

I did buy a Challenger Air Filter for my old 172B. Couldn't tell any difference. If you had a Power flow exhaust it might help, but I'm not too excited to fork out another $200 for one.

I put a K&N on the 180 this past annual. I did get better than an inch MP but that was after a year on an old Brackett. With 8 months behind me, the K&N seems like it will be more efficient and deliver consistent performance over time.
I think that you will have to take a good look at your average flying (T/O&L) conditions and make a judgement call. I'm not sure that the better breathing filters are designed for shovels full of dirt. Most of the off airport landings I make here in the Northeast or in the Mid-Atlantic are in grass, not gravel beds or canyon floors. If that were the case I would probably have thought a little harder about my choice. For what I do, I'm satisfied with the performance I get from the filter as well as the protection.
Here's something that will help you make an informed decision as to whether or not you should get a better breathing filter. Remove your present filter and reach back into the induction hose or airbox. If you can't do that, remove the cowling and check the induction hose and airbox from that end. If you feel grit, your aircraft is already ingesting dirt. It's either coming through the filter or through an airbox with worn bushings. Assuming that the airbox bushings and gasketing are good and you don't feel any grit, you might consider a better breathing filter since your flying habits aren't taxing your present filter media. As an aside, if the airbox bushings are worn, the suction will actually open the door enough to allow dirt to get past the gasketing during run-up. All that dirt your prop is kicking up is finding its way into your intake. Unless your airbox is tight, don't perform a stationary run-up over dirt. It's no different than a run-up with the carb heat on.

FWIW
TJ

K&N or Donaldson? I don't think you would notice the difference between the two but everybody loves choices.

I run a K&N in two of my vehicles and on my Rotax powered airplane. The key is properly oiling them. They must not suck too bad as they've been around forever and are used on a wide array engines.

One of very few unbiased tests to shed some light on the airfilter question.
http://www.bobistheoilguy.com/airfilter/airtest1.htm

I liked the idea of his test using a secondary filter to show any pass through dirt from the primary test filters. We have secondary filters on all our farm equipment and we never clean the secondary, just replace it occasionally or when dirty. We regularly clean the primarys though. We also have a 1969 Rupp snowmobile that I finally gave up on and parked a couple winters ago. Funny thing is it never had an air filter even when new. The 20hp Sachs still has enough compression to jerk the hand cord loose from your grip on a pull with a warm engine. Cleaner winter air and snow evidently wasn't much of a problem for that engine. The point being the filter has to match the conditions.

I have looked at the dirt on my plane from sitting all winter in the hangar. It is coated everywhere, so I imagine its that way under the cowling on the engine too. How many of us block off the inlets with cowling plugs while in storage or tape them off outside while parked in the blowing wind. Think about when you start the engine and the prop blast drives that dust down the skeet tubing to the carb heat. Maybe some blows out the carb exhaust but some stays in too, just waiting for you to pull the carb heat knob letting the dirt bypass the air filter on its way in to your valves, pistons and rings.
Something to think about.