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Let's talk engine air filters

5K views 37 replies 16 participants last post by  bulwnkl 
#1 ·
1) How often do you change your engine air filter
and
2) What brand do you use?

I was changing my engine air filter every year and using a no-name filter from Amazon. I am driving much less (about 5k miles per year) so I am now changing it every two years and still using a no-name air filter from Amazon.

Your thoughts?
 
#2 ·
1. I follow the recommended interval, 20,000 km.

2. I use OEM.

@tickerguy made a guide where he installed a gauge and that tells you if the filter is dirty.

I also don't drive that much in the past six months so it's possible that I might reach two years before I replace the filter. I don't see any problem with it as long as filter doesn't disintegrate. I'm not sure about the "no brand" you are using.
 
#9 ·
I was running the AEM cold air intake for the past 5 years. Just swapped back to stock box with aFe filter as of a few weeks ago.


If anyone is looking for a CAI...
:oops: Actually, I might be, considering a supercharger install.
Just make sure you check it and wash it regularly. It will develop holes much quicker than you think. I put maybe 30k on one once and found big holes in it under a close inspection, which had clearly been developing for years.
Lol, I would never inspect it more than 10k apart, hopefully, that didn't happen so far.
Oiled filters are crap compared with OE paper ones in terms of WHAT they filter. They were a good technology -- in the 1950s.

An engine ingests one teaspoon of dirt over its entire service life. The question to ask yourself is how rapidly you'd like that teaspoon of dirt to get into the engine, because that, more than anything else, determines how long your engine runs barring a catastrophic mechanical failure.

I have over 200,000 miles on my "6" and nearly 300,000 on a TDI Jettta in my driveway and neither burn any appreciable amount of oil between service intervals. The reason for that is that I run OE air filters and pay attention to any source of unfiltered air into the engine (such as vacuum leak) and fix them, if I find them, immediately.
I replace my oil every 3-5000 miles. Hadn't noticed any issues, obviously the K&N one isn't for maximum cleanliness, but rather the few extra hrsprs with a tune lol.
 
#8 ·
Oiled filters are crap compared with OE paper ones in terms of WHAT they filter. They were a good technology -- in the 1950s.

An engine ingests one teaspoon of dirt over its entire service life. The question to ask yourself is how rapidly you'd like that teaspoon of dirt to get into the engine, because that, more than anything else, determines how long your engine runs barring a catastrophic mechanical failure.

I have over 200,000 miles on my "6" and nearly 300,000 on a TDI Jettta in my driveway and neither burn any appreciable amount of oil between service intervals. The reason for that is that I run OE air filters and pay attention to any source of unfiltered air into the engine (such as vacuum leak) and fix them, if I find them, immediately.
 
#13 ·
Got like 3-4ish hp with a tune on a dyno with the current filter, as compared to a used OEM one. Maybe it was dirty but I doubt it, either way, I'm planning to supercharge soon so this air filter doesn't matter. I heavily oil my filter and it is extremely clean, the more eco-friendly reusable aspect is what I like about it most, can just clean it anytime with soap and water.
 
#14 ·
I think this logic is correct: An oiled filter, to my way of thinking, has to have less-dense media to start with than a paper filter, otherwise when it's "charged" with its initial oil-application it'd be more restrictive than the paper media filter... The initial oil-charge takes up some space and occludes the filter to some degree. With dust-loading it'd get worse from there. If the paper filter has effectively zero pressure loss across its media during its effective operating life then it makes no sense to use a less-dense/less-effective filter system, which was said above.
 
#16 ·
Unless you are building a race car, just use the Mazda OE filter. There is very little to be gained or saved by switching to a different air filter.

The Genuine Mazda air filter costs $20 which is a drop in the bucket in terms of annual operating costs. Per the owner's manual, on the most aggressive maintenance schedule (severe conditions) it should be changed every 5,000 miles. The theoretical Road Warrior that does 30k miles/year in hot, dusty or stop-and-go environments would be spending $120/year on Genuine Mazda engine air filters. I'd wager that most of us subjecting our cars to normal driving conditions are changing our engine air filters once a year or less.
 
#17 ·
If you put a restriction indicator on your airbox as I did you will likely find the real interval is >30,000 miles in reasonable conditions. The point of the indicator, however, is that one good drive in dusty conditions and the filter is likely toast as such conditions could easily expose it to hundreds or even thousands of times the "usual" loading rate. Thus being able to look at what the maximum intake plenum vacuum (AFTER the filter and before the throttle plate) experienced since last reset is extremely useful, and having it there "in your face" means that every time you pop the hood to check the oil or similar a glance at the indicator tells the tale.
 
#20 ·
K & N air filters are great but really not for "regular folk".
OEM paper filters are GREAT for regular folk and even then, they screw that too !

Living in the Southwest; HUGE DUST STORMS, and all sands/debris flying because it is desert AND dry, engine air filters get dirty/CLOGGED fast !

Every TWO(2) times I change oil, air filter inspection is done/mandatory, thus getting an idea of filter contents.
(DON'T ask how often that is, it's secret), but air filter gets dirty no matter what !)

Race cars have need to change/wash/replace air filter and extensions related to that aspect of air intake/engine management MORE OFTEN, but normal persons are not worried about seconds, just getting home and sitting in front of TV with their bowl of cereal(if that is what your choice is...). So that is a different story IMO.
Living in a somewhat humid climate is good for air filters 'cause moisture drops air pollution/removes it from circulation. (Just like pollen in the mornings on your car)

Buy good filters or...
Replace more often the "cheaper" ones and notice where and how you drive(i.e.. FAST driving intakes more air that slow/lower engine RPM's, therefore more oil and air filter changes, tires, etc...)

THANKS !
 
#25 ·
K & N air filters are great but really not for "regular folk".
OEM paper filters are GREAT for regular folk and even then, they screw that too !

Living in the Southwest; HUGE DUST STORMS, and all sands/debris flying because it is desert AND dry, engine air filters get dirty/CLOGGED fast !

Every TWO(2) times I change oil, air filter inspection is done/mandatory, thus getting an idea of filter contents.
(DON'T ask how often that is, it's secret), but air filter gets dirty no matter what !)

Race cars have need to change/wash/replace air filter and extensions related to that aspect of air intake/engine management MORE OFTEN, but normal persons are not worried about seconds, just getting home and sitting in front of TV with their bowl of cereal(if that is what your choice is...). So that is a different story IMO.
Living in a somewhat humid climate is good for air filters 'cause moisture drops air pollution/removes it from circulation. (Just like pollen in the mornings on your car)

Buy good filters or...
Replace more often the "cheaper" ones and notice where and how you drive(i.e.. FAST driving intakes more air that slow/lower engine RPM's, therefore more oil and air filter changes, tires, etc...)

THANKS !
Very well spoken, I used to live in the Middle East and the dust there was terrible, paper filters are mandatory there too, the oiled ones would get clogged in a week. However I live in one of the most humid places in New York, hence why the K&N was a good choice for me. Also personally I'd prefer getting cheaper filter's if I were to go with paper since I love servicing the car often and wouldn't mind changing it every 10,000 miles or less. However, I've seen OEM filters last for 6 or more years with owners who don't even know about them and the engines still work great, and for the most part the filter is great after a small dusting to remove big debree. I wouldn't trust a cheap one to last that long however.
 
#24 ·
Yes, you must make a hole downstream of the filter. Be SURE to seal it. The restriction gauges should either come with or have available a rubber or other type of seal.

The automotive restriction gauges are nice, but not at all reliable. I have and have had them on everything from pickups to heavy equipment for decades. We’ve collapsed filters and intakes on trucks, had heavy equipment engines be choked to the point they wouldn’t do anything but idle, all while the gauges said the filters were clean. Changing air filters fixed the problem.
Happily, they’re fairly inexpensive. The trouble is that it can be difficult to determine whether they’re good or bad. After all, if you knew what the intake vacuum was, you wouldn’t need the gauge, LOL.
 
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#26 ·
After all, if you knew what the intake vacuum was, you wouldn’t need the gauge, LOL.
How about installing a vacuum gauge? You install a new air filter and observe the vacuum gauge at idle. Then you mark where the needle is stabilized. Then you rev the car at let's say 1500 RPM and maintain it there so you can observe where the needle is pointing. You also mark that on the gauge.

With that, you now have a basis for "normal operating vacuum pressure".

Do I make sense?
 
#31 ·
Hard to say, since Mazda doesn’t publish, or may not even have, a spec.

Donaldson, marketer of the FilterMinder brand of restriction gauges, generally marks them ‘red’ (replace) in the general area of 20 inches of H2O. K&N marks the one they market at a noticeably lower level, but I can’t recall off-hand whether it’s 15 inches, or 10 or 12, or just what.

I’d use a lower restriction for most consumer automotive applications than for agricultural or other heavier equipment. Donaldson’s default may be more appropriate for even some heavier automotive diesel applications.
 
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#28 ·
Magnahelics? Manometers? Vacuum gauges? Years ago I would have jumped at these alternatives. As far as filters, I usually buy the Napa Gold series. Both engine and cabin filters. But now, at the ripe old age of 73, I look at each “about” every six months. If they appear dirty, I change them. If pristine white, like new, I shake them out, reinsert, keep on motoring.

For now, it’s “Keep It Simple, Stupid,” & “Don’t over think it.” These days, my OCD-ness is now confined to vacuuming out the bottom of the engine filter box for any debris laying around in there. And since I don’t smoke, the cabin filter really doesn’t get that dirty.
 
#29 ·
Thats good, Rick i am the same been known to drive the poor souls around me!! Lol.
KISS> definitely wise here. I think taking out the air filter clearing the debris out and running the shop vac over the air filter may help me in my car keeping.
Appreciate you feedback and everyone else's
 
#33 ·
Remember, one teaspoon of dirt is all your engine will ingest between new and destroyed.

How fast would you like that teaspoon to go into the engine?



Hint: Don't buy Fram, and definitely do not use old-style oiled pieces of trash, which will let ridiculous amounts of dirt into your engine. This is why no OE uses this sort of air filter any longer; oiled filters were in fact common in lawn mowers -- in the 1950s.
 
#34 · (Edited)
For reference:

As of last year, Fram claimed their CA11259 was 99.01% efficient (coarse dust test, not fine) in both Extra and WM Ultra versions, and Wix claimed their 49247 was 99.5% efficient (coarse dust test).
I tried a couple other brands, but they (and Mazda, too) either don’t know or won’t say. Last I checked, K&N’s just-cleaned efficiency was way below that, which translated to an order of magnitude or few more dust passing through it.

I love the re-clean-ability and reusability of the K&N, but I don’t love anything else about it.
 
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#36 · (Edited)
Ref: Bikeprof 20.
I cannot say I would rush home for a bowl of cereal, I usually have my muesli and a banana in the morning and certainly not in front of the tv, but at the dining room table. I was going to say oats, but when you get past a certain age that is just a memory of youth.
But yes I aggree with him.
What is wrong with every time you check your oil, tyres and screenwasher to remove the cover of the airfilter and check the business side, knock it out on the floor.
As we are not so dusty in Britain ( though present heatwave excepted), air and fuel filters are 24k miles, we are more damp than dusty , though we could do with some rain now as they are starting to ban hosepipe use.
 
#38 · (Edited)
Because the efficiency numbers look better when the test is run with coarse, perhaps?

What very little I’ve seen suggests that air filters for vehicles up through class 4 (F-450 size) are most often tested with coarse dust, whereas heavier-duty (up through class 8 trucks) vehicle air filters are perhaps more often tested with fine dust.

Here’s a handy file showing particle size distribution. ISO 12103-A4 is ISO 5011 coarse. ISO 12103-A2 is ISO 5011 fine dust:

K&N’s website has a particle size distribution table formatted in a different way. Some may find this arrangement more readily apprehensible:
 
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