Intake dirt

[Gray]

Somewhere I've seen a study on the amount of dirt which travels through the various types of paper and cotton air intake filters and most (all) air filters failed miserably. Have any looked at the old school trick of putting a foam primary filter in front of the Nissan, K&N, etc paper or cotton filter in use to cut down on ingested dirt? On the 05+ PF's it should be a fairly simple square cut to fit snug in the filter box size.

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[NVSteve]

Somewhere I've seen a study on the amount of dirt which travels through the various types of paper and cotton air intake filters and most (all) air filters failed miserably. Have any looked at the old school trick of putting a foam primary filter in front of the Nissan, K&N, etc paper or cotton filter in use to cut down on ingested dirt? On the 05+ PF's it should be a fairly simple square cut to fit snug in the filter box size.

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I posted a link to a test of various filters somewhere on the forum here, but I can't find it now From memory, I don't believe they had anything good to say about any of the foam filters. You do have an interesting idea though. Maybe even something as simple as 1/4" foam (or thinner), in conjunction with the paper filter, would reap some rewards. Hmmm, it would be a very cheap experiment, that's for sure. I suck in dirt and dust probably more than most other members here (only because of the conditions where I live), so I'd be a prime candidate for testing.

If we can decide on which type of foam to try, as there are probably hundreds of different types out there, then I'll look around locally and/or order it if necessary.

[Gray]

Thanks Steve, this might be the air filter study you are refering to;

http://www.bobistheoilguy.com/airfilter/airtest1.htm

Also some info here on True flow filters and replacements;

http://www.trueflow.com/index.php

[NVSteve]

Thanks Steve, this might be the air filter study you are refering to;

http://www.bobistheoilguy.com/airfilter/airtest1.htm

Also some info here on True flow filters and replacements;

http://www.trueflow.com/index.php

That's the link I was referring to, thanks. Now these guys are truly full of themselves: http://www.pecuniary.com/synthetics/airfilters.html

I wonder if the typical auto parts stores carry foam filters. I could bring in my OEM paper filter and see if they have anything close in size, then take everything apart, modify & put it in. I know it wouldn't win any beauty contests, but I'm curious if it would help or not.

[OurPathfinder]

We use a K&N filter in our '07 PF. It was $40 for the filter and then we got the oil/cleaning spray for $7. They suggest cleaning the filter at the standard cotton/paper replacement intervals as your stock filter unless you drive on dirt roads or in dirty conditions in excess then to do it more frequently.

[Gray]

We use a K&N filter in our '07 PF. It was $40 for the filter and then we got the oil/cleaning spray for $7. They suggest cleaning the filter at the standard cotton/paper replacement intervals as your stock filter unless you drive on dirt roads or in dirty conditions in excess then to do it more frequently.

I've looked at the K&N filters but as I drive dusty gravel roads the oilable cotton filters from various studies look to let through more dust to the engine. With the microfiber threads and fabrics available one would think that some company would have developed an efficient ULPA engine filter by now.

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[LittleStevie]

We use a K&N filter in our '07 PF. It was $40 for the filter and then we got the oil/cleaning spray for $7. They suggest cleaning the filter at the standard cotton/paper replacement intervals as your stock filter unless you drive on dirt roads or in dirty conditions in excess then to do it more frequently.

I had a K&N in my '05, but switched back to OEM cellulose after seeing some of the "studies" on particulate bypass. The K&N's are meant to provide lower pressure drop for power and racing applications, but I do not believe that they protect the engine as well. You also have to be very careful not to over-oil, as the oil can go downstream and mess up your mass air flow sensor.

[Gray]

I haven't had a chance to do a full search but it appears as if Donaldson is the only company so far who has stepped up to the plate and is providing nanofiber air filters for Nissan vehicles at this time. The Donaldson company from their website and from talking with their online reps don't have info as to what is being provided for VQ40 engines but from talking with Amsoil service people Donaldson appears to be providing nanofiber air filters through an Amsoil special order;

http://www.donaldson.com/index.html

http://www.amsoil.com/StoreFront/eaa.aspx

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[NVSteve]

I haven't had a chance to do a full search but it appears as if Donaldson is the only company so far who has stepped up to the plate and is providing nanofiber air filters for Nissan vehicles at this time. The Donaldson company from their website and from talking with their online reps don't have info as to what is being provided for VQ40 engines but from talking with Amsoil service people Donaldson appears to be providing nanofiber air filters through an Amsoil special order;

http://www.donaldson.com/index.html

http://www.amsoil.com/StoreFront/eaa.aspx

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Have you run across any third party testing or product reviews for this? Sounds good, but so do all the other mfr. websites. I'd certainly be interested, as I don't really have much confidence in the K&N I was running & am now back to OEM.