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Was curious as to how often you guys change you air filter in the engine? I have a 2021 SX and I’ve taken it out and cleaned it once so far as it was alittle dusty and had a leaf in it. Do you suggest using OEM replacement filters as well. Appreciate the help!
 

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I change yearly whether it needs it or not. Pet peeve of mine. We live in the mountains where there are a lot of dirt roads currently. I use NAPA filters. Cabin air filter gets changed also. Filters aren't that expensive.
 

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Was curious as to how often you guys change you air filter in the engine? I have a 2021 SX and I’ve taken it out and cleaned it once so far as it was alittle dusty and had a leaf in it. Do you suggest using OEM replacement filters as well. Appreciate the help!
I go by the "normal" maintenance schedule, you may consider the "severe" maintenance schedule
 
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99 Kia Elan 1.8L
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I go by the "normal" maintenance schedule, you may consider the "severe" maintenance schedule
That would be more appropriate as it would be based on the volume of air ingested by the engine.

i.e. no point in changing an engine air filter that's only done 2K miles in 12 months.
 
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I know better, now, but I kept looking - on the top - of the filter on my '11 Sedona. It looked fine, so I didn't change it. I got it in '14 and only finally changed it THIS YEAR when a video I was watching clued me in that it was the BOTTOM of the filter that collected the crap.

Opened the enclosure, took out the filter, and WOW. I'm not sure how air was still passing through. Must have been doing a good job, though because the top of the filter looked pretty good.

I'll probably replace it yearly, now.
 

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I go by the normal, recommended maintenance schedule through my dealer's service department. Especially to keep the powertrain warranty in good standing.
 

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2015 Kia Sorento LX I4 AWD, 36K miles
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Was curious as to how often you guys change you air filter in the engine? I have a 2021 SX and I’ve taken it out and cleaned it once so far as it was alittle dusty and had a leaf in it. Do you suggest using OEM replacement filters as well. Appreciate the help!
I follow the normal maintenance schedule to satisfy the warranty even if it isn’t dirty. I buy the filter at the dealer but change it myself.
 

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'11 Elantra (Still) '11 Optima (still), '12' Optima Turbo (gone), '21 Telluride.
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Folks change engine air filters, to their engines detriment, much too early. A filter that needed changed will be hideous. An engine air filter passes the MOST contaminants when it's new. Meanwhile a dirty filter has no effect on MPG, and usually only little HP detriments. A few percentage points at most.

When exactly they should be changed depends a little on objective. A fleet operated taxi might run to 15" of water column before it was changed (a lot). An OTR semi operation might change at 10" so they don't lose any power on steep climbs and etc. But the folks chiming in so far have probably not even been close. I'd venture nothing over 5" of water column.

There is just scads of information out there supporting all these things, yet folks continue to buy into myths and service shop scare tactics. Do a few searches yourself!

As to what do use, just don't use a K&N or anything like that. Actually most folks will need one every 40,000 miles or so, so I use a factory and call it unless I'm doing something really really nasty.

As to brand names of quality aftermarket, Donaldson is where it's at in quality air filtration for the ICE world. In the performance world assuming S&B made one, it's them. Otherwise factory is the right move. Cleaning then: You can knock some dirt out wo harm, but never wash or blow through a paper filter.

Heck, here, study this: Look at the filters and realize the were filtering BETTER and had only minimal power loss.
66-6000RWB Test Results.pdf - Google Drive

Now this is about off-road powersports, and we get dirty fast and power matters, but most car owners would simply poop themselves to think see something even 1/2 of that. Yet at 1/2 that dirt level it would be better for their engine then changing it. BTW, same test as cars use, same "dust" same everything. Just different filter sizes tested to their limits
 

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There is just scads of information out there supporting all these things, yet folks continue to buy into myths and service shop scare tactics. Do a few searches yourself!
How about you post a few reliable links that support these personal opinions of yours.
 
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I settled on changing engine intake air filter every 4th oil change which is about 16 months for Sportage and 2+ years for Forte lately.
 

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How about you post a few reliable links that support these personal opinions of yours.
Sure, happy to help. I'm a little surprised the link I included doesn't show enough. Let's recap that:
  • Pictures of what a truly dirty filter looks like
  • The exact testing process used in the auto industry, right down to the dust type selected,
  • Graphs showing inches of water table vs power loss.
  • Filtration rates

However, I'm happy to give you more:


  • Now I wrote that, but there are a number of good discussions and links to other research sprinkled throughout. Post #33 has some more discussion on inches of water column as an example.
  • In that post I mention a deeper analysis I elected not to post, and that I did so out of respect for the mfgs. Some of them are that forums sponsors and I wanted to keep it inoffensive to them. Another called me back asking to not be quoted because they felt they'd been too candid. But I don't mind attaching that article here. It has well over a dozen industry links and related, so at least you'll see where the insight I've shared comes from. (and reference to the person concerned w/being quoted is gone)

As you'll see from the attachment I've a considerable time investment - well over a hundred man hours, including talking to air filter mfg's directly. I'd like to think I'm reasonably informed, but of course that's for each of you to decide.

BTW, since I never posted it's probably full of typos. It's also something of a deep dive.

See attached, supporting links are at the end under "Reference Links".


My best to all,

-d
 

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Argh. With apologies, I'm going to take that attachment down. It's just too critical of a mfg that I respect. I think less of their one product, but I don't want to be part of detracting from a business I otherwise believe is quality oriented.

Sorry guys, ethics has to come before defending an air filter post for a car, and this keeps nagging at me.

Ron, or anyone else that wants to take the time (considerable) and will keep the document confidential (please), PM me an email address and I will email you the deeper dive research article. I ask only that it not ever be publicly released.

Thanks guys,

-d
 

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With the turbo, I also change mine yearly. A supercharged engine has a lot more air crammed into it through the air filter than a normally-aspirated engine of the same displacement. Now maybe it could actually go for a lot longer, but consider this - suppose its only about 10% blocked? That means it can flow a little less air at a given pressure. This means there will be a little less power. There will be less exhaust pressure to run the turbine so these effects obviously can affect the performance of the engine. At the small price of an engine air filter every year to help maintain performance and efficiency, there is no logical argument against it.
 

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With the turbo, I also change mine yearly. A supercharged engine has a lot more air crammed into it through the air filter than a normally-aspirated engine of the same displacement. Now maybe it could actually go for a lot longer, but consider this - suppose its only about 10% blocked? That means it can flow a little less air at a given pressure. This means there will be a little less power. There will be less exhaust pressure to run the turbine so these effects obviously can affect the performance of the engine. At the small price of an engine air filter every year to help maintain performance and efficiency, there is no logical argument against it.
Well, there is a logical argument against it --- it may not be necessary. The same is true with oil changes at less mileage than the manufacturer recommends. Obviously, if you live in a dusty place or do offroading, then change it yearly. But for the vast majority of owners, changing it as the manufacturer recommends is all that is necessary. The manufacturer has a warranty on your engine, and when they set oil and filter mileage, it is there to prevent engine damage. I know a lot of you don't believe in testing your equipment and then using that data to make decisions, but logically, that is the way to do it. If you think your filter is 10% blocked in a year, then what about changing it every 6 months when it is 5% blocked or every 3 months when it is 2.5% blocked. When I belonged to a car club, we actually did test the flow of air filters. We only found 1-2% blockage in airflow in a year for the vast majority of members. In modern cars, the airflow is baffled and closed. Heavier particles fall away before the air flow actually hits the filter.

Will you cause harm by changing the oil and filters more often? Unless you break something, no. Does it cost money to do so? Yes. Is it necessary? No. Again, depend on science and testing to make maintenance decisions on your car -- not feelings.... And the belief that if the filter is slightly blocked, it will affect engine performance is just not true. All parts have tolerances. This is true for air filters as well. The air filter will allow more air flow than your engine can use. That's the way it is designed. It is a safety measure. Engine oil is designed to be effective even when the additives start breaking down and the color gets darker. Again, there is a margin of safety built in.

Now I've tracked cars in the past, and with modified engines, most manufacturer air flow systems are inadequate. In the olden days, with carburetors and direct air (not baffled) systems, filters would not last long. Technology and engine design has changed some of the rules of thumb we used to use. Manufacturers have done a lot more testing especially due to warranty issues and legal costs. You can stick to the old beliefs and waste money -- and if it makes you feel better, so be it. For me, I meticulously stick to the manufacturer's recommendations until the warranty is up. Then I depend on occasional testing when I lengthen intervals. In all of my 60 years of owning cars, I've never had any engine problems keeping to the manufacturer's recommendations. And I take the money I save and either give it to charity or the grandchildren....
 

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Excellent post, as usual, but I am referring to supercharged engines only in re the engine air filters. Normally-aspirated engine air filters perform exactly as you said and a typical change interval is 36K miles. Supercharged air filters are subject to many times more volume of air to be filtered per mile and are about the same size in surface area in our Sportages as the non-boosted ones.
 

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1sax:

I'm glad RVOLL's time on the site allows him to be more trusted. Think on these things a bit, see it if fits for you:

1) NA, supercharged, turbo, etc usually doesn't matter. Typically the air filter is sized appropriately to the air flow where "size" is sq inches of filter media. I'm certainly not saying some mfg won't shortchange you, but generally not.

2) The key then is your environment, not miles or induction method. In desert racing you can plug a filter in a day, and in fact guys use things like K&N's (junk as a final filter) as pre-filters just so they can bang them out or swap them at the end of the day and not have clogged the internal (decent) filter.

While most guys use the sight test, you're really looking for inches of water column restriction. In a truly high performmance application you're gonna want to replace it at maybe 10" of water column. In a day to day car application you could even go 20".

My sense is nobody looked at the S&B test results I linked to (looked very hard anyway), but you'll see pictures of filters that were just god-awful dirty and weren't affecting HP in any significant way. And that's not some made-up test, they used THE automotive industry test and the correct test dust (Arizona fine). The data is applicable to anything, so size to suit.

All:
In candor, this isn't much of a thing. I sort of regret mentioning common beliefs (everywhere, not here per say) get this wrong. To be clear over the life of a filter the "when new" reduced filtration isn't significant, and you could change every time you changed your oil and not create any real engine wear. You'd just have thrown time and money away for no benefit and some loss (generally insignificant).

Again off-road, you'll usually see a fine trace of dust in an intake tract post filter. That came from the first hours/days of use. Once the filter picked up some contamination the filtration efficiency comes up while restriction is basically unaffected. This certainly applies to cars too, it's just a much longer cycle.

The only other thing worth mentioning in that the contaminants of concern to an engine are the really small ones. Anything from maybe 2u to 25u in size. I'm coming to understand that particle size is pretty common in high density urban area's. LA, Chicago, NY, etc, and I believe it's a result of GDI releasing lots more fine particulate. Anyway, the point is those particles are so small it's much harder to tell. I still think anything non racing can go way long than most guys think, but really only a manometer will tell you. Something like this:

K&N Filter Minder Push-In Air Flow Indicator (autozone.com)

If you look around there in no clear consensus on how much restriction is "correct" to warranty a filter change, but the performance world generally uses 10".

Best of luck to all,

-d
 

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Excellent post, as usual, but I am referring to supercharged engines only in re the engine air filters. Normally-aspirated engine air filters perform exactly as you said and a typical change interval is 36K miles. Supercharged air filters are subject to many times more volume of air to be filtered per mile and are about the same size in surface area in our Sportages as the non-boosted ones.
Actually, your turbocharger uses only about 40% more air and not "many times more volume of air". Let's say that an air filter in an NA engine can go for 36k miles. Then, in a turbo, if you have the same exact filter you will have the same amount of air pass through in about 25K miles. It's really just math and fact. It's the amount of air that passes through that determines how "dirty" the filter is. Lots of people try to justify their actions based on faulty assumptions or just guesses. It's important to know the facts and be able to do the math.... Remember that there are tolerances built into all maintenance calculations and that in actuality, filters are just fine even after they tell you to change it. What I hate most about things like this is that service people and part manufacturers are just trying to make some extra bucks by taking advantage of people's lack of knowledge. The same is true for oil changes. I understand the feeling of wanting to take care of "your baby" by more frequent service actions. It just doesn't make logical sense if you know the facts. I am not going to change the minds of people who are going to believe what they want to believe. It may be a part of my OCD to not like waste -- even if it is cheap waste -- so I continue to try and make logical arguments. And if you knew me, and my aggressive driving and the cars I've owned, I am certainly not an environmentalist.
 
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Volume pretty much directly proportional to boost. In round numbers one atmosphere is 15psi. 8 psi of boost is 50% more air (round numbers guys) 15-16 is twice the air demand, etc. Mind you I'd expect larger filter media and boxes in FI applications (making this moot), but that's not always true.
 
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I change me engine air filter as needed but do not exceed the recommendations from the service manual. Its pretty easy to inspect an air filter. I am usually following the severe service interval and seem to not have all the issues that many post here. My driving style, along with the wife and kids, will never mimic any silly 'bench testing'.

Also, I've used KN filters in many vehicles with no change in oil condition when compared to OE filters. So, no sudden uptick in metals or dirt. I guess it depends on the owners ability to service/clean/oil it properly and with an acceptable interval.

Interval depends on driving style and local debris.

If I drove it with a lead foot and only got 12mpg, it would fill up more rapidly than if I drove it with a feather foot with 25mpg.

For example, when I commute on the graded roads, it would fill up rapidly with dirt/sand. When I drove in winter climate with plenty of road sanding, it would fill up more rapidly. During a highway only commute, noticed the engine air filter not catch much at all. So, don't fall for any blanket time/mileage interval and inspect often enough.

Air filters are like fluids....oil/coolant/ATF/brake.... do whatever you want and reap what you sow.
 
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