I think I am going to defer to the posted links of scientific testing. Those suggest that K&N filters let quite a bit of dirt through. If your humble opinion is that it wont hurt, so be it I guess. The fact is, fine grains that get through your air filter add substantially to piston ring wear, and raise damaging silicon levels in your oil which definately contributes to engine bearing wear.

The notion that the filter is the restriction is also false and born out by testing. In fact the K&N only flows better as it lets more dirt through. As dirt accumulates the stock paper filter actually flows better and protects better. The window where the K&N flows better in the real world is very small, after that, it becomes the restriction you are trying to avoid. All of this is not IMHO but substantiated in testing.

The only minor restriction in the intake tract is the 2" opening at the end of the stock intake. That can be fixed for under $10 as previously mentioned. It isn't the stock filter, which in my truck is a generously large cone shape.

Good Luck with K&N filters. You can buy into the advertising hype or independant test results. I simply suggest doing some homework before getting too set on an opinion.

 

That's a bit counter-intuitive isn't it? As the filter accumulates dirt it flows better?

 

Thats not what he said though. He means that as the filters load up with dirt, the OEM style filter flows better than the KN does.

The fine particles that get past can contribute to engine wear. Its just not worth messing with them. They are not as good and cleaning, drying, oiling etc is a hassle.

By the way, I wouldn't even run KN on my lawn mower.

 

The oil causes the dirt particles to stick together, preventing air from moving around them. May seem counter intuitive to a point, but the test doesn't lie. On the test, the K&N flowed better for a simulated 500 miles, after that, the paper filter outperformed it all the way to saturation. Here is the link to the test article.

ISO 5011 Duramax Air Filter Test Report

 

Thanks for the clarifiction guys I may have made that sound a little confusing.

Just remember that it is OK to have bought a K&N. Everybody makes mistakes and millions of people have done it with K&N filters. Don't feel like the Lone Ranger, just change it out for something that is proven to work better.

These engines are capable of lasting a really long time. My company truck is a 5.4L with 255k miles on it. Still runs great, rattles a little in the morning but pulls hard and uses minimal oil. Don't shortchange that lifespan with a filter that not only lets dirt through, but then becomes a performance restriction itself.

Good Luck

 

I put a K&N CAI on my 97 F150. I dynoed it before & after the install. The only change was about 4 hp at wot. I took it off after the oil from the K&N caused many MAF problems. There are many mods that will ad hp but IMHO a CAI isn't one. Maybe on a performance motor it would help but on a stock motor stick with the factory intake.