[long-time-dmax]

do a little reading on K&N filters before you decide to stick with that filter. DIRT in your motor! I watched a video on here a couple of days ago. Including that video, I have never seen a test where K&N wasn't DEAD LAST in filtering out dirt when compared to normal paper type filters.

 

[long-time-dmax]

This is the filter shootout mentioned earlier. Good comparison but I don’t like the way he did the small particle test. I’ve ran K&N Filters on both our 4 Runners with NO issues and a slight increase in gas mileage. As long as you don’t over oil them they work great. I would not use them on a turbo engine thou.

Below is another test done to ISO standards. Story behind this one is back in 2002, shortly after I bought this truck I was about to order a K&N filter for it because I'd heard good things about them. I was looking for a place to order / buy a K&N from so I did a google search. I think it was the first link that came up, but it was the original web page that the report was published on. After reading the report and looking at the graphs, there was absolutely NO WAY I was going to put a K&N on my brand new truck.

As an aside, I have a cousin that bought a Ford excursion with the 7.3 PS. He still owns it as far as I know but about 3 years ago (~300,000 miles), his truck wouldn't start. He had it towed to the Ford dealer. The mechanic told him that the reason it wouldn't start was because the injection system uses oil pressure to fire the injectors and his motor didn't have enough oil pressure to fire them. He then told my cousin that this was probably due to him running a K&N filter. I never knew he was running that filter in his Excursion or I'd have sent him a link to the test results I mentioned above. I also have no clue if 7.3s use oil pressure to fire injectors but am just taking the mechanic's word for it. I do know that 300k miles is nothing for a 7.3 PS.

Anyway, I'm sure this has been posted on this site many times in the past (it's been around a LONG time) but this guy tested many different filters and did multiple tests (unrestricted flow, restricted flow, filtering ability and such) and in damn near EVERY category, the K&N came up last. It also happened to be done with Duramax air filters which is why it came up in my google search for a Duramax K&N filter. The link below is not the original page where I found the report but apparently someone thought highly enough of the test and report that they saved it as screen shots and reposted it. The video posted above is just confirmation of what this guy posted ~19 years ago.

ISO 5011 Duramax Air Filter Test Report

 

[long-time-dmax]

I think the correlation was that the k&n filter let in too much dirt, that ended up wearing out his oil pump.

Yeah, that and possibly the dirt wore his main / cam bearings to the point where there is too much clearance to maintain oil pressure?

 

[long-time-dmax]

If your proof of oiled cotton air filters being terrible is just the PF test, then that's not much proof in real world applications, imo. I've watched many of that guy's videos and find several of them to be fairly informative. The one on air filters involved dumping a large amount of contaminants into the airflow in a very short time. So if you're operating your truck in such a dusty environment, like through frequent sandstorms, maybe you shouldn't run an oiled filter. If you run up and down the highway in relatively clean air like most of us do, there's nothing wrong with an oiled filter from a filtration standpoint. I ran one for a couple hundred thousand miles, my motor was still in very fine condition and I had the oil analysis to back up my point that the air filter was doing it's job. My Si level was plenty low enough and lower than some guys' oil analysis that were running stock filters.

If you're just going to drop a flat panel K&N filter into a stock air box, the air box is very likely to be as much or more of a problem than the filter itself. The factory flat panel air boxes? Now there's something that truly is terrible. A complete new CAI such as an S&B with oiled filter is a fine filter setup.

There's also this: ISO 5011 Duramax Air Filter Test Report

And no, it's not a video with some guy explaining it all to you but it was done to ISO standards and all the data is there for everyone to read. Along with explanations as to what it all means... and the data is TERRIBLE for the K&N. But you have to spend a few minutes to read and understand the data. Certainly not as easy as watching a video though...