Foam filter catches black dust

[Jim]

OK, I have been reading all the stuff that says paper filters better, but there seems to be more to it.
I have a Ford diesel tractor that I have modified with a foam pre-filter on the air intake. After one season of mowing the pre-filter will be black. Without the foam filter on, the paper filter never turned black. My conclusion is that the foam will catch very small stuff that can get through the paper. The foam filters might not catch all the dirt, but I bet they are better and catching some of the very very fine dirt. I still do see a small amount of dust in the intake downstream from the foam.

[ February 16, 2005, 08:43 PM: Message edited by: Jim ]

 

[3000GT VR-4]

quote:

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Originally posted by Jim:
OK, I have been reading all the stuff that says paper filters better, but there seems to be more to it.
I have a Ford diesel tractor that I have modified with a foam pre-filter on the air intake. After one season of mowing the pre-filter will be black. Without the foam filter on, the paper filter never turned black. My conclusion is that the foam will catch very small stuff that can get through the paper. The foam filters might not catch all the dirt, but I bet they are better and catching some of the very very fine dirt. I still do see a small amount of dust in the intake downstream from the foam.

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Could the oil on the foam filter be turning the dust black? If so, it would not appear black on the paper filter, even though it is there.

 

[metroplex]

Paper has more efficient filtration, nuff said. Look at coffee filters.

If I were in a lab and wanted to speed things up, using a K&N cotton gauze or Amway Foam filter would do the trick but by allowing a lot of particulates to end up in the beaker screwing up the experiment.

 

[oilyriser]

Maybe the dust is turning the oil on the foam black, which exaggerates the amount of black dust. I have noticed, though, a black film downstream of the paper air filter, on an old car. Fine soot does tend to get through.

 

[GT Mike]

quote:

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Originally posted by metroplex:
Amway

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[Jim]

Vibration has an effect on how well paper keeps dust from passing through. Tap on a vacuum cleaner filter while it’s running and you will see dust blow out the exhaust. Modern cars have the filters mounted away from engine vibration which a big improvement over having the filter vibrating on top of the carburetor.
Oiled foam is not sensitive to vibration.
I am not saying foam is better, but it does have advantages in some situation. Real world testing sometime reveals things not found in lab testing.