Originally Posted By: tdi-rick
This has been discussed at length in the past.
Air filtration is of paramount importance to engine longevity.
In the heavy duty off road industry (dozers, excavators, etc) there Are mostly two elements in the housing, as well as centrifugal pre filters.
Yes, the pre filters are used because of the immense dust loadings, but the two element filters are used to get efficiency well above 99%.
I know two different blokes that have trashed new CAT dozer engines in less than two hours after an engine change when some intake ducting wasn't done up properly.
Regarding media, a friend is a filtration research engineer, and at present you can't go past cellulose fibre (paper) for cost/efficiency. Absolute efficiency also leaves oiled cotton gauze and oiled foam well behind. Never seen a K&N or UniFilter in a dozer
There are synthetic medias recently developed that have better flow/efficiencies, but are still exxy. Donaldson, Mann-Hummel and Cummins hold the patents on most nearly all of them. (FWIW, I've been told that the big three's R&D budgets exceed K&N sales $ each year.)
One company that does offer a very high flow, high efficiency synthetic media filter is R2C. Currently made for racing applications, they appear to know their stuff.
You just described the exact system we use. FWIW we have dusted engines in less than 30 minutes with an intake leak sucking in huge amounts of dust.
In those applications, the air filter is the most important element