Somebody Explain Air Filters To Me
#11
#12
#13
A diesel engine doesn't meter air, so as long as the filter meets the CFM requirements of the engine cubic inches and estimated compressor capability, the filter will work on the engine.
There used to be a formula--something like the filter at 50% capacity should be able to flow 10% over the maximum requirement of the engine package, or something like that...I remember reading it once in a racing publication but cannot recall it completely.
There really isn't such thing as a "too big" air filter for a compression ignition engine like there is for an engine that relies on metered air and vacuum to work properly.
There used to be a formula--something like the filter at 50% capacity should be able to flow 10% over the maximum requirement of the engine package, or something like that...I remember reading it once in a racing publication but cannot recall it completely.
There really isn't such thing as a "too big" air filter for a compression ignition engine like there is for an engine that relies on metered air and vacuum to work properly.
#14
Just my humble no-mind opinion, though.
I think there are more issues with filtration quality over filtration quantity....keeping all the dirt out of the engine is where the competitive edge(s) lie rather than in actual airflow amounts.
But I don't make any money off selling performance goodies so I probably don't know what the F I'm talking about....
#15
Yup...pretty much.
Just my humble no-mind opinion, though.
I think there are more issues with filtration quality over filtration quantity....keeping all the dirt out of the engine is where the competitive edge(s) lie rather than in actual airflow amounts.
But I don't make any money off selling performance goodies so I probably don't know what the F I'm talking about....
Just my humble no-mind opinion, though.
I think there are more issues with filtration quality over filtration quantity....keeping all the dirt out of the engine is where the competitive edge(s) lie rather than in actual airflow amounts.
But I don't make any money off selling performance goodies so I probably don't know what the F I'm talking about....
Then there are different types of air filters. You have dry filters and oiled filters, oil bath filters and even filters the employ a centrifuge. Then there are also different materials that they make the filters out of.
There are 2 ways of making your filter filter better. One is by making the cloth denser so it traps more. However it usually doesn't flow as well. That is why most of your aftermarket air filters are so much bigger and have a lot more surface area than the stock ones. They can also flow longer without getting plugged up.
Also the shape of the air box plays a part in how much they will flow but I don't think that is what your asking for.
#16
#17
if the filter is too thick the pressure drop on the filter can be restrictive, we used to change out the air filters based on pressure drop and saved the district tens of thousands in dollars on filters because they were being tested every month and changed as needed.
knowing how much it would filter is one thing, but how much of a pressure drop and how long it takes for it to collect enough dust and dirt is prolly what your lookin for?
knowing how much it would filter is one thing, but how much of a pressure drop and how long it takes for it to collect enough dust and dirt is prolly what your lookin for?
#19
if the filter is too thick the pressure drop on the filter can be restrictive, we used to change out the air filters based on pressure drop and saved the district tens of thousands in dollars on filters because they were being tested every month and changed as needed.
knowing how much it would filter is one thing, but how much of a pressure drop and how long it takes for it to collect enough dust and dirt is prolly what your lookin for?
knowing how much it would filter is one thing, but how much of a pressure drop and how long it takes for it to collect enough dust and dirt is prolly what your lookin for?
#20
well back when work was easy, we changed out filters when the pressure drop was 1.0 inches of water. each unit was different because of the square area of the filters and the cfm that each unit draws. some unit were very inefficient, one example we had was two identical buildings with the same units, one had 5 pleated rows of frames that had 16x25 frames, we put in 20x25 filter inserts because of the more surface area making it more efficient that what it already was. in total the unit had 25 filters arranged in a 5x5 zig zag maximizing the surface area. the initial drop was .1 and it would take a year for it to reach 1.0 a point where the filter has become inefficient and needed to be changed.
another school with the same unit has only 10 filters arranged in a flat face taking up the same front air passage space for the unit. the initial drop with clean filters was .6 and in a month and a half it would reach 1.0
the standard one inch clean house filter has a pressure drop of about .1
but that drop also has to do with the amount of cfm being drawn through the filter, the surface area of the filter media, and how well the filter flows, because the pressure drop is the change in pressure from one side of the filter to the other measured in inches of mercury.
a drop of one inch of water is about .036 psi, not much but its a huge difference
another school with the same unit has only 10 filters arranged in a flat face taking up the same front air passage space for the unit. the initial drop with clean filters was .6 and in a month and a half it would reach 1.0
the standard one inch clean house filter has a pressure drop of about .1
but that drop also has to do with the amount of cfm being drawn through the filter, the surface area of the filter media, and how well the filter flows, because the pressure drop is the change in pressure from one side of the filter to the other measured in inches of mercury.
a drop of one inch of water is about .036 psi, not much but its a huge difference
Last edited by 2500HeavyDuty; 07-19-2009 at 06:39 PM.