Why do all PERRIN intakes come with foam filters?
The principle of how foam air filters work is simple: The PERRIN Performance “Open Cell” polyurethane foam is saturated with specially developed filter oil. This filter oil clings to the strands of the web-like cell structure of the foam. The oil is now suspended directly in the path of the incoming air charge. As air passes through the filter, dirt particles cling to the oil and remain as the air passes unimpeded into the engine. The entire volume of the filter is a working surface. As the outer strands become loaded with dirt particles, the inner wetted strands begin trapping dirt, allowing the entire thickness to be utilized. Without the surface loading seen in other filters, foam filters maintain 90% to 100% efficiency even as mileage increases. When the filter is sufficiently dirty, it can quickly and easily be cleaned, re-oiled, and ready for re-use.
