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painless

Well Known Member
I am finishing up my conditional inspection and am wondering how often it is recommended to replace or recharge the airfilter in our FAB's.

The easy response would be every year, but I am more interested in actual number of hours and under what conditions.

Thanks in advance
 
If you have the K&N filter you never replace it, just clean it and put it back in.

Any auto parts store should have the cleaning K&N cleaning kit.
 
painless said:
I am finishing up my conditional inspection and am wondering how often it is recommended to replace or recharge the airfilter in our FAB's.

The easy response would be every year, but I am more interested in actual number of hours and under what conditions.

Thanks in advance
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Jeff,

I take a good look at mine through the intake opening periodically. When the filter appears dirty to me, I remove it and clean it. That's usually every year and a half or two years.

For reference, I fly about 75 hours/year, typically off of hard surfaces in a non-dusty environment.
 
K&N Says

According to their website the filter filters better when dirty. Flow does not seem to go down as it gets dirty. Since I don't know how dirty is good I clean mine every two years or 400 hours, wcf.

I have also replace the filter. Avgas seems to shrink the rubber portion of the filter which is probably no big deal but I got a case of filters years ago or $4/filter so why not change them out when they shrink.
 
What Gary just said... if you're on a paved field and dust and sand/dirt is not a problem, fly on. These K&N filters are great!
 
Thanks guys. I have been using the "peek through the air intake" method for the last couple of years. The filter looks pretty clean to me, so I have not messed with it.

They work better when they are dirty? Works for me! :p
 
The STC instructions...

...that apply to certified aircraft owners who have paid $150 for a $4 filter - ahh... the price of FAA paperwork...:mad:

Quoted from their FAQ -

Q: How many times can I reclean the air filter?

A: Filters can be cleaned up to 25 times or 2500 hours.

Q: How do I know when to clean the air filter?

A: Filter must be cleaned every calendar year, 100 hours or sooner in dusty conditions.

Of course, being Experimental, these do not apply, but should be a good guideline.
As a comparison, my Tiger K&N filter has more surface area for the same 180 HP than the one Vans supplies.

Full instructions here -

http://www.challengeraviation.com/Challenger Air Filter Cleaning Instructions 8-31-05.pdf


- I got mine before Challenger (the K&N aircraft dept.) doubled their prices. It ends up that the filter is a 60's Dodge one, but it is stamped "FAA/PMA" in the rubber surround - what a scam!
 
There is one more step.....

N941WR said:
If you have the K&N filter you never replace it, just clean it and put it back in.

Any auto parts store should have the cleaning K&N cleaning kit.
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Just clean it, re-oil it, and then put it back on.
 
N941WR said:
True. The oil is in the cleaning kit.
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Mine gets cleaned with Simple Green, gently rinsed with water, dried on the ramp in front of the hangar, and rejuvenated with oil that comes out of the big red Marvel Mystery Oil jug. :)
 
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Use the manifold pressure gauge...

....if you have one. On the IO-520 Conti's we used to do ag work in, we were told that if your takeoff MP is an inch lower than ambient, your filter is dirty. Around 1/2" difference was normal drop for a clean filter.

Regards,
 
Great tip!

pierre smith said:
....if you have one. On the IO-520 Conti's we used to do ag work in, we were told that if your takeoff MP is an inch lower than ambient, your filter is dirty. Around 1/2" difference was normal drop for a clean filter.

Regards,
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Thanks Pierre!
 
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