air filter brand and change interval question

So, aside from oil and filters, what are people doing for air filter change intervals, do you follow the maintenance schedule in the owners
manual, or ????
Most of my vehicles have called for changes at around 15 or 20K miles and that's more or less when I change the filter. Only exception is if I are driving on dusty dirt roads behind people, then I might change it after that kind of trip, just to be safe.
What about brands, do most of the denizens here revile Fram air filters like they do their oil filters?
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IMO, Fram makes an OK air filter, as compared with other brands. My problem with them is that more and more of their products are being made in China and Israel, especially their fuel filters. They layoff the North American worker, but yet they want their former (currently jobless) employees to buy their product. Excuse me, Honeywell. How many of your top paid executives lost their jobs to a Chinese worker?
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If you've been changing your filter between 15 & 20,000 miles and that works out for you then there is no need to ask others about an interval change. You also answered your own question about changing the filter sooner if driving on dusty roads.
I change air filters between 30,000 & 40,000 My manufacturer (GM) says 30,000..
Tried a Fram Fliter in the Bonneville once, was tight when I went to remove it and ended up tearing off one whole side of the rubber gasket that wrapped around it.
I use OEM filters from an Auto Parts store.
harryface 91 Bonneville 320,854 05 Park Avenue 93,589
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When I change the oil, I inspect the filter and I bang it on the bumper and knock some stuff off of it. If it looks very dirty, I change it.

I'd at least inspect it.

The thing about air filters is that if they aren't working effectively, the result is fairly evident. --scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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On 15 Dec 2009 10:35:53 -0500, snipped-for-privacy@panix.com (Scott Dorsey) wrote:

I read somewhere that banging them like that was a big no-no. It would cause trapped dirt to become available on the wrong side of the paper and would get sucked into the engine next time you started it. I have no idea if that's true.

If they get clogged it might be evident, but if they don't filter very well how would you ever know?
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If it gets clogged, with modern cars it's very noticeable on acceleration but it's often not noticeable at all at low speeds and at idle.
If it doesn't filter well, you'll notice it because when you clean the throttle body and intake, it will feel gritty and not just gummy. I have sadly experienced that feeling on cars using K&M filters.... --scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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Back in the 1970s, I owned a 1962 Ford Falcon I had recently bought.One time myself and a buddy were driving to Bloomington,Indiana, I wanted to check out a Ford Model T a guy had advertised for sale in Hemmings.Somewhere in Kentucky that night, my car quit running.We looked under the hood, the air filter was completely clogged up.I removed the air filter and my car started up and ran just fine. cuhulin
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I don't mind Fram air filters. Without test equipement you can't really be sure about the quality of the media, but Fram's looks about the same as other "national brands." Still, I see no reason to pay more for Fram air filter if a Motorcraft air filter for my Fords are on the same shelf for less.
One thing that is interesting to me is the idea that changing your air filter too often is actually a bad thing. "The SAE paper by Marty Barris (SAE Technical Paper No. 952557 titled: 'Total FiltrationTM: The Influence of Filter Selection on Engine Wear, Emissions and Performance' ) offers two important conclusions:
a.. "The level of ambient dust concentration can easily overwhelm other factors in terms of influence on engine wear. It is therefore important to match the air intake filtration system design to the anticipated ambient exposure. And here's an interesting one-: b.. "Too frequent air filter change intervals can double engine wear rate, especially if changed within the first 30% of the air filter's life. "The practice of removing an air filter element to blow it clean is plain stupid. This malpractice, which can lead to engine wear rates being trebled, still occurs on the false economy basis of trying to extend the service life of the air filter element. A well meaning but badly trained technician thinks he is being thorough in servicing the air filter, or replacing it prior to reaching the optimum life of the element. This happens in workshops without supervisors even being aware of it."
The following is from the "Nanofibers in Filtration Applications in Transportation" listed link below:
"For most engine air filters, the function of the filter and the corresponding engine wear are based largely on dust cake filtration. The formation of a dust cake on the filter media changes many important factors in the function of a filter media, including filtration efficiency and pore size distribution. Engine wear rate has been shown to be significant during the early portion of an air filter's design life (Figure 9 in http://www.donaldson.com/en/filtermedia/support/datalibrary/052024.pdf ).
"While vehicle manufacturers are specifying longer life air cleaners and longer maintenance intervals, the actual service interval for air filters varies widely depending on the sophistication of the vehicle end-user and the maintenance staff. The most sophisticated end-users are large fleet operators with several thousand vehicles. Air cleaner maintenance is typically performed based on filter restriction using a restriction indicator on the vehicle. Maintenance decisions are largely made based on economic factors, and trained personnel provide oversight on maintenance intervals and filter selection. The decisions are based on a complex interaction of factors, including filter design and efficiency, filter maintenance interval, filter and service cost, and engine wear rate.
....
"Consumers must also make maintenance decisions about the air filters in their cars. This user group is relatively unsophisticated in their knowledge of filter maintenance and function. Air filters are perhaps the most easily serviced but least understood parts on a vehicle. Other common replacement parts on a vehicle such as tires, wiper blades, oil and oil filters work best when new. However, this is not the case with conventional air filters. Since most air filters rely on the formation of a dust cake to improve the performance of a filter media, over-servicing can lead to dire consequences from inadequate engine protection.
"Air filter over-servicing is common for light vehicles. Light vehicles are generally not equipped with filter restriction indicators. Air filters are often inspected by maintenance personnel during oil changes. In spite of the typical manufacturer's recommendation of at least a 30,000-mile change interval, it is common for dealers, service stations and quick lube businesses to recommend more frequent air filter changes. Given the frequency of oil changes and air filter replacements at quick lubes, it is expected many light vehicle air filters are changed much more frequently than manufacturers recommend.
"While this over-servicing phenomenon is frustrating to those who understand filter media performance, the filter industry has not sufficiently educated customers how air filters function. Not surprisingly, filter manufacturers, distributors, dealers, service stations, and quick lubes have economic incentives to change and sell more air filters. It is also understandable that consumers believe air filters work best when they are new (like other parts) and have a clean appearance."
Other links:
http://www.filtercouncil.org/techdata/tsbs/89-3R3.html http://www.tomorrowstechnician.com/Article/4991/component_connection_the_dirty_little_secrets_of_filters.aspx
Ed
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"C. E. White" wrote:

Did you read the article? Donaldson is peddling their Nano-fiber technology which they claim does not suffer from this limitation that the filter needs to cake with dust before it starts working properly. They claim their filter will work right straight out of the box. And guess what? Other filter manufacturers also claim the same thing.
-jim

http://www.tomorrowstechnician.com/Article/4991/component_connection_the_dirty_little_secrets_of_filters.aspx

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/052024.pdf).

Fram introduced their air-laid "depth" (variable density) media in the late '70s.
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