Why Are Air Filters Important?

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Originally Posted By: Pajero
Pantyhose worked well when Mt. St. Helen's blew in 1980. I live in the desert (large sandbox) and installed a Snorkel. People make fun of me because they think it's for water. It's because of dust. Ever going wheelin with a bunch of 4x4...the dust is horrid. Cyclonic filters are the best for worst conditions...



Respectfully,

Pajero!




There was a pantyhose shortage during the eruption period due to the popularity of using pantyhose as a pre-filter. Unfortunately the ash was like fine glass so transmissions and diffs all got hammered. Not to mention windshields.

The vehicles that held up best were ones with the oil bath air filters.
 
I had a lesson in air filters not too long ago, to compare specs for purchasing. I had a little money left on an Amazon gift card, and I have read decent things about Luber-Finer. I figured I would pick up one for my 2011 Fusion, an AF2785. It came in the mail and it looks pretty good. Nice rubber seal, nice sturdy pleats, very neat and tidy. Then NAPA has their filter sale on, so I buy a NAPA Gold for my car as well, a 9114. I get it out of the box to compare, and it has WAAAY more number of pleats, but the depth is probably 1/4" less at least than the AF2785. So, which one would be preferred? # of pleats or pleat depth, if filter efficiency was identical? Which media typically has better efficiency- the AF's fleece, or NAPA paper? Pics are below.


 
Just today I was staring at several bags from my kirby vacuum. HEPA...fabrication came to mind. Thinking of wrapping my cone filter on the jeep, making a carcass so that the bag won't collapse onto the filter.
I'm fortunate to be in the soggy pnw, but wheeling kicks up enough dust to make up for decades.
 
Seems like some of you are promoting name brands as "great" without any specs? I don't care what name is on the box, or how good the marketing people are, gimme the specs! If they aren't listed freely, contact the mfr and ask for their efficiency ratings. Ask:

-give them a specific part number for you rig because they sometimes use different media for different applications
-efficiency using what test protocol? (mainly you want to know if it's ISO 5011 and coarse or fine dust... it's always coarse because the number is higher)
-Ask for filter area (which is the amount of media used before it's pleated). I have had mixed results getting that, but if you see lots of pleats, you know it's got a lot).
-if they won't tell you, move onto another brand!

Then you sit back and evaluate media vs efficiency. Some of the cheap filters I looked at years back had very efficient media per inch, but not much of it!

Then look at the general sealing quality and construction of it.

If it meets these criteria, buy one and test fit it. Fits good?

Run a WOT and get the new filter reading with a restriction gauge. If you have it, compare that with the reading from a new OEM filter. No restriction issues?

Run with it and don't mess with it for a good long while unless the restriction gauge indicates. I won't say never look at it, but don't obsessively R&R the filter. Every other oil change maybe (depending on you OCI... judgement... in my case they are 2-4 years on some of my rigs, so I might pull it at that point). In my experience, filters that face up are most likely to benefit from gently and carefully vacuuming off leaves and big stuff that collects. Use judgement. The main thing is not to injure the sealing mechanisms on removal. I like K&N filter grease for this, use it at first install and again if you need to pull it. I have used other stuff, but won't advocate it.
 
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While it is true that there are vast differences in the filtering ability of aftermarket filters, would it be safe to say that buying OEM part is the safe bet ?
 
Originally Posted By: Smokescreen
While it is true that there are vast differences in the filtering ability of aftermarket filters, would it be safe to say that buying OEM part is the safe bet ?


For myself, I prefer not to bet. I attempt to find out!

The old Spicer test (google "Spicer air filter test") gave a lot of good indications by brand for the 2003 era for a Duramax application anyway) in that, the OEM Delco rated pretty high. If that holds true today, I do not know. I have been particularly impressed with Honda OEM filters. They are a lofted synthetic media (for my application) and it appears that Fram reboxes Honda filters (last time I bought one). The one in our Accord is about 8 years old now and has barely tipped the restriction gauge (not all that many miles)

All that said, the OEM at least has some internal standard and the better aftermarkets usually strive to meet that at a minimum, or a generic industry spec. The last time I polled industry experts,about 4-5 years ago, the spec everyone was shooting for was 98.5% percent minimum on the coarse test. Some were better. It would depend a little on how big a filter they could package under the hood and still make rated power. They might have to tweak efficiency down a skosh to meet airflow requirements in a tight package.

An efi car with a MAF can use the cleanest air of all.

Overall, I think the top aftermarket brand names, especially the premium varieties, are going to meet a pretty high standard. It's the house brands and "white box" stuff that you should worry about. Still, if you are serious about all this, research your part number!
 
Originally Posted By: circuitsmith
Restriction gauge FTW:

https://www.bobistheoilguy.com/forums/ub...42K#Post4600881


Great link! Great test! Great lesson! Hats off to you, sir.

I noted in that thread some people trying to "one-size-fits-all" it. Doesn't work. For that car in that environment, 42K is what it took. Same car in a different environment could be 20K or 90K. That's the beauty of the gauge!You can "Three-Bears" it.

From what I know, that type of filter media is one of the more efficient types.
 
Great post and work Jim. Very good to see ya back on here. I have read your historical old post and learned a lot from them. You add a lot of real world information on here.
 
Originally Posted By: Jim Allen
Seems like some of you are promoting name brands as "great" without any specs? I don't care what name is on the box, or how good the marketing people are, gimme the specs! If they aren't listed freely, contact the mfr and ask for their efficiency ratings. Ask:

-give them a specific part number for you rig because they sometimes use different media for different applications
-efficiency using what test protocol? (mainly you want to know if it's ISO 5011 and coarse or fine dust... it's always coarse because the number is higher)
-Ask for filter area (which is the amount of media used before it's pleated). I have had mixed results getting that, but if you see lots of pleats, you know it's got a lot).
-if they won't tell you, move onto another brand!

Then you sit back and evaluate media vs efficiency. Some of the cheap filters I looked at years back had very efficient media per inch, but not much of it!

Then look at the general sealing quality and construction of it.

If it meets these criteria, buy one and test fit it. Fits good?

Run a WOT and get the new filter reading with a restriction gauge. If you have it, compare that with the reading from a new OEM filter. No restriction issues?

Run with it and don't mess with it for a good long while unless the restriction gauge indicates. I won't say never look at it, but don't obsessively R&R the filter. Every other oil change maybe (depending on you OCI... judgement... in my case they are 2-4 years on some of my rigs, so I might pull it at that point). In my experience, filters that face up are most likely to benefit from gently and carefully vacuuming off leaves and big stuff that collects. Use judgement. The main thing is not to injure the sealing mechanisms on removal. I like K&N filter grease for this, use it at first install and again if you need to pull it. I have used other stuff, but won't advocate it.


Thank you.
 
Originally Posted By: rooflessVW
Originally Posted By: demarpaint
True and a lot of people pay a lot of money for a K&N filter air intake kit, or whatever they call it. [The kind of air filter you apply their oil to and wash and reuse] to increase HP and have no clue what kind of damage they're doing to their engine. Expensive in the case of K&N can be bad too.

Sorry, but have you ever heard of a K&N causing an engine failure?

Fried MAF from over-oiling, sure. Maybe a K&N isn't 99.9% efficient at a half micron, I'll give you that... But over the course of typical ownership, what harm does it really do? Heck, even extended ownership.


Lot's of heightened emotions and hyperbole against K&N on here. It all depends on the filtering efficiency of every brand, including OEM, for the specific application. Blanket statements don't move discussions forward. My, "I've used K&N for 25 year w/o issue" included.
 
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