914-6 factory air cleaner - vs - K&N's, Which unit performs best Options

[david63]

Currently have a factory 914-6 air cleaner on the 3.0 in my 74 conversion. Question for the group is which system breathes better, the factory system or the K&N filters? I like the look of the two filters with the watershields but if the factoy system is better performance wise I guess I should stick with it? Please advise.

[Cap'n Krusty]

Having measured the actual filter area on a number of K&N elements and compared them to the filter area of the stock paper elements, I can honestly tell you there is an ENORMOUS difference in the filter area, measured in square inches. Here are a few pix. (Both filters shown fit the same application.):







Note the obvious differences here. Were you to remove the border material and flatten out the pleats, you might be REALLY surprised just how big the difference is. (In some applications, there may be as much as 5-10 times more filter area in the stock paper filter element!) If there is less media, and the unit flows more air, it is obvious the air passages (pores in the material) must be much larger. That being the case, K&N (and others) have to use oil on the filter media. The air passing through the larger holes deposits SOME of the contaminants on the oil surrounding the holes. However, a significantly larger amount of contaminants are allowed to enter the intake airstream and go into the engine, vs. the OE paper filter element. The quantity of oil applied to the filter element is fairly critical, especially on cars which use electronic mass airflow sensors. The oil destroys the MAF in pretty short order. That expensive air filter seems like chump change when you have to buy a new MAF as well as a stock air filter, and have the car scanned and the CEL reset.

A few years ago I read an article written by an engineer with a mining company in one of the northern mining states. His company invested in K&Ns for their giant off road dump trucks. His conclusion was that the cost of complete overhauls made necessary by their use dwarfed any possible savings and convenience they could have EVER realized from the use of those filters. Save a few hundred bucks per truck per year, and spend tens of thousands, again per truck, on engine work, per year.

It's your car, and my opinion, albeit somewhat substantiated. Your choice.

The Cap'n