I have been seeing posts by few people, who have done replacement of stock filter with K&N/Green Cotton/Pippercross.
I would like to know how safe it is for engine?
One of the benefits of a high flow air filter is that, unlike regular filters, you donít have to change it every year. All you have to do is clean it about every two years or so. This is because they donít get clogged as quickly or as easily, yet they offer better air flow and better filtration of the air going into your engine. And if your engine is getting more air, then it can perform better. In fact, a high flow air filter can actually increase your horsepower by about 3 to 5 HP and increase your torque as well. At the same time, this can lead to increased fuel efficiency. How? In some of the more expensive units, the filter comes with a cold air intake unit. This is installed to pull air from the outside of the car instead of the hot used air inside the engine bay. Going back to science class, cold air is more dense and will therefore burn better, hence improving the performance of your engine.
However, donít think that a high performance air filter has no bad to it. There are problems that can arise from installing one of these. Do note that these are not guaranteed to happen, but it is a possibility. One problem that has been noted is that because of the increased air intake, high performance filters can actually expose your engine to more debris and contaminants. It can also increase the amount of dirt and dust in your oil and put more wear on the internal elements.
as particles which are of the size of 5-25 micron is known to cause maximum damage to your engine.
Although these aftermarket companies boost of high degree of dirt filtration, why no OEM is using them?OEM stock paper(HEPA) filters will do a good job until they get wet (at this point they become useless, and sometimes stop the engine).
BTW, HEPA filters use a similar (if not exactly the same) cloth (flannel, I believe) filtration for the low particulate level clean rooms required by the semiconductor industry; so not all cloth or reusable filters are poor as implied by the article.
Another problem is that, especially with cold air intakes, is that water from the road (accompanied by mud and other forms of dirt) can splash up and soak your filter and/or introduce water to your engine. There are ways to avoid this, however, such as by buying a hydroshield and making sure to not drive through roads with high water. Although, it is to be noted that you do pay for quality with these filters. The better the quality you buy, the less you risk any harm to your engine.
For example K&N used cotton with oil, depends on oil to catch dust particles , some times is feel like it going back old technology what was in use in 70-80's, i used to see foam airfiler soaked with oil to improve on the filtration.
I did see some PU based foam filter essentially using a layer of oil like good old days and claiming the wonderful results.
I would like to open this thread for discussion on pro's and cons of the these filters.