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Air filter service life

Messages
8,467
Location
Colorado
I saw an air filter on a diesel truck that had a device on it that pops out when the air filter needs changing? How come they do not put stuff like that on gas engine vehicles?
 
Messages
2,095
Location
IL
Thread starter
Cost and LCD like Dick said. OTR trucks rack the miles up so fast for them to simply change at an arbitrary mileage set artificially low due to lcd morons, they would be changing ridiculously often. And truck filters aren't cheap. For a passenger car mfr to spec 30k intervals, that is about 3yrs avg.: $5-10 every three years...big deal. That is safer for them than the alternative. And to put an indicator would cost more money to build.
 

Patman

Staff member
Messages
21,965
Location
Oakville, Ontario
I finally found someone who could help me figure out how to open my airbox, I had to disconnect all the stuff around it and take the box right out of the car. When I looked at the filter, it was VERY dirty, and I suspect it's the original AC Delco. My car has 83,000 miles on it. Good thing was, the inside of the airbox was super clean, no dust at all. I put in a new Fram air filter. I was at the dragstrip, so I was able to see before and after performance differences. My trap speed went up by 0.2mph, so it was about a 2hp difference. [ April 28, 2003, 05:29 AM: Message edited by: Patman ]
 
Messages
35
Location
Northern California
I have a 88 toy 4X4 2.4 FI I use for work, I drive once a week thru about 50 miles of agricultural area(rice/tomatoes), but on the main highway or freeway, I change my air filters about once a yr (9K) and at that point the filters have about 1/16 inch or more of ag field dust/seeds/bugs/etc at bottom of ea pleat, I waited(by accident) 2 yrs or 18K to change yr before last, wow!! the pleats were almost full to the top with same stuff, mainly bugs/seeds. I would never change a filter by just mileage now but also by actual condition of the filter. The tractors in the ag area and winds keep a lot of this stuff airborne constantly. Normal city driving where I live I probably could go 2 yrs on a change. Wife's vehicle here locally never shows much at all in the pleats at 2 yrs or 18K.
 
Messages
8,711
Location
Nothern USA
Most of us don't have an easy way to directly measure the air flow through a filter. We know most filters become more efficient and more restrictive as they fill up with dirt. We can tell the filters start out oversize since the dirt mainly accululates right at the inner folds suggestiong that is where most of the flow is. I trust the OEM's more than aftermarket. All the above suggests hanging on to the OEM as long as possible. A restrictive filter should increase engine vacuum, more so at higher RPMS. I do have a vacuum gage I could connect and gentle rev the engine. So replace the filter when a A [Confused] n oil analysis shows unacceptable levels of silicone. b Vacuum goes up. c It is so old you are afraid the paper may crumble.
 
Messages
903
Location
CA
You can get a mercury manometer at a bike store for about $35. Much more acurate than gauges costing 10 times that.
 
Messages
561
Location
springdale, ar
i have to agree with jason here. the thing that many don't realize is the amount of filter area these pleateds have. the OEM BMW filter has 10 SQUARE FEET of filtration media. the filter in the picture has a dusting of dirt on the upper 1/8th of the filter? as long as the pleats are holding (pleats stop working if they come in contact with each other) and the filter is physically sound, why change. there is no evidence of face loading on this filter, and the loading material seems pretty uniform and small. that being said, i would also agree with jetfishn, depending on the local conditions, filter life is a major variable. i drive mostly highway, but live one mile back on a dirt road. my filters start looking pretty skanky about 20k (thats a technical term there). i would LOVE to have a filter change indicator. may look into fabbing one up. anyone who finds an easily installable one, drop me a line.
 
Messages
874
Location
Pacific NW
Good work, Jason. I'm cheating by coming into the thread late, but... would have said the old filter had 5-10% restriction from new. Used to play with water manometers for measuring intake ducting improvements. Not terribly precise, but it was surprising how well a "dirty looking" filter continued working. BTW, I've wondered about visual pressure drop indicators for a more deterministic approach. Our recent work on oil filter tests exposed me to some nice little PSID switches. I'll post when I figure out something that works and doesn't cost a fortune. David
 
Messages
1,759
Location
Elizabeth City NC
My drive to work is pretty consistant so I have done some milage test with three different filters. The first filter is the original OEM mazda miata filter from Japan with 48 pleats. Looks like the one pictured above. It has 20-25 thousand miles on it. It averaged 28.5 Next was an OEM filter from the dealer. It has only 20 pleats and has 5 thousand miles on it. It averaged 29.5. Next was the Napa Gold with same number of pleats as Japan original ie 48 and with zero miles. Average milage 31.5. Seems like filters start to effect milage fairly quickly. I will see how quickly the milage changes with the new Napa Gold. Same gas used in all test,same tire pressure,constant mph using cruize control and simular weather.
 
Messages
901
Location
Northern Illinois
quote:
[/QB]Originally posted by Patman: I put in a new Fram air filter. [/QB]
You are probably up on such things, but I thought I would mention anyway, that I have seen reports of the fine pink fibers detaching from a Fram filter and melting onto the MAF sensor, it acts like insulation or something. Beware.
 

Patman

Staff member
Messages
21,965
Location
Oakville, Ontario
quote:
Originally posted by dickwells:
quote:
Originally posted by Patman: I put in a new Fram air filter. [/QB]
You are probably up on such things, but I thought I would mention anyway, that I have seen reports of the fine pink fibers detaching from a Fram filter and melting onto the MAF sensor, it acts like insulation or something. Beware. [/QB]
The Fram filters I have on my wifes car and on mine don't have any pink fibers, the media is entirely white.
 
Messages
901
Location
Northern Illinois
If the fibers are white I expect you are in the clear. The problem filters were those that show a cross section of a fiber on the box. It is a triangular shaped cross section extruded fiber and is supposed to catch more dirt. I guess the fibers/filters were orange rather than pink on bringing my memory up to 60% efficiency, (GR)
 
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