Clean air...ahhhhh

[mlh]

"A very old fat man"... That describes most of us.
Lynwood

[Tom S.]

quote:Originally posted by mlh

"A very old fat man"... That describes most of us.
Lynwood

Yeah, but we don't collect dust - just wrinkles!

[mlh]

And we are still on the green side of grass. Life is good!!!
Lynwood

[Dave Nowlin]

I will go further. All HVAC filters as well as these automotive filters build a filter cake on their face. This cake is porous and allows air to continue to flow while this filter cake traps dust as the pore structure is actually smaller than the pores in the filter. The filter will continue to get more and more efficient until it finally becomes too restrictive to air flow and must be changed. This is why I recommend my customers change filters according to pressure drop and not appearance. The super small hydrocarbon particulate isn't the real danger to our engines it's the airborne silica and other abrasive particles. These particles are much heavier for their size than some other things and are therefore harder to stop when accelerated in an airstream. They tend to puch through a filter media which is too open. Did someone say K&N? That filter will catch airborne lint and ther light for volume particulate very well but the dense abrasive particles will tend to paas through. If you change your engine oil and filters very often much of this harmful particulte will be removed. If you are environmentally concious and choose to use synthetic lubricants along with their longer change intervals, you would be very wise to use OEM air filters.

[Ozz]

The first picture is one i took at a house..a dirty house with 2 toddlers toddling around the house and a big black dog laying on the return register. The filter was not in the furnace..hadn't been in it for years. I tore the furnace top off and saw the 'dog sweater' wrapped around the inside of the A-coil, I peeled it off in one section, laid it on the floor and took this picture. This is what happens when you don't install a filter in your furnace.
The second small picture is a return air in a bar. Always filthy, the bars air..
Makes you want to get up and change the filter, doesn't it??

[mlh]

Dave what you said about the heavy particles makes perfect sense, and I had never thought about that. This explains why you can dust an engine with a K&N filter and K&N can claim they trap such a large % of the dirt coming through it. Now I get it thanks.
Lynwood