K&N filter after 50K miles of service (Pictures)

[barlowc]

I took some pictures of the K&N filter in my Nissan when I pulled it today for its 50K mile cleaning. This filter was put in when the odometer had only 56 miles on it.

Clean Side

Dirty Side

I post these not to start another thread debating K&N filters. Rather, I just wanted to share some pictures.

The post-filter side of the airbox and intake was clean with no sign of the fine black dust that some other K&N users have reported. UOAs that I did at 28K and 43K had Silicon count of 12 and 13, so it seems to be doing a perfectly fine job of filtering.

I've cleaned the filter, will properly re-oil it once it dries, and plan to run it for another 50K unless there there are signs of any problems in UOAs.

 

[Lead Shoes]

They seem to filter very efficient when they start to get dirty, far better than when they are clean.

As long as the UOA's look good, keep going with that routine

 

[MetalSlug]

not bad, but im a big fan of paper type air filter, change out every year or 12k miles, see it dirty, throw in the trash and put in new one , and I know I have clean air filter without worried oil stuck to my mass air sensor .

 

[Chris142]

Did you Wipe the tube out with a white cloth? How is the throttle body ?

 

[hounddog]

Not that I'm a expert but if his UOAS are good that tells the story. I'm not a K&N fan as many have posted high silicone counts when UOA wa silicone using K&N. Actually this is first proof I've read about one doing a good job. But it is. DIRTY does filter better until a peak!

 

[Chris Meutsch]

If you're doing the UOA's and they are OK, then you are OK with the K and N setup. I used to use one and I just chickened out.

 

[chubbs1]

Looks...dirty as heck I guess the filter did its job and a good one at that. Thanks for posting!

PS Hoping to see your UOA soon, I will be posting some of my UOA's of the Pentastar engines after they are flushed out a little.

 

[hardcore302]

I got 13k on mine, I want to clean it sooo bad, but I'll wait.

 

[barlowc]

Originally Posted By: Chris142
Did you Wipe the tube out with a white cloth? How is the throttle body ?

Yep, and there was no sign of anything! Clean as a whistle.

Originally Posted By: hounddog
this is first proof I've read about one doing a good job

A post about the K&N in our Saturn is here. It's just as good. I am having no problems whatsoever with the K&N filters that I'm using in both of our vehicles. Would I buy them again if I were to do it over? Probably not. But I'm just posting to show that they're not everyone using them is having problems.

 

[Artem]

Goodness gracious. I'd at least pull it every OC or every other OC and tap out any loose dirt, leaves, etc etc. Just blindly running it that long is not the best practice.

 

[barlowc]

Originally Posted By: Artem
Just blindly running it that long is not the best practice.

Who said anything about blinding running it for 50K?

 

[Jim Allen]

Barlowc: You did exactly right letting the filter get nice and dirty. If you were gentle in the cleaning, you have another 50K to look forward to.

For all of you, here's a quote from an engineer at Parker Filtration that is the basic precept of air filter maintenance :

"Ninety percent of the lifetime amount of dirt that passes through a filter does so in the first 10 percent of use."

Any filter has an initial efficiency rating and a final efficiency rating. The initial rating is done after the filter has had 20 grams of either fine or coarse grade dust applied at a specific flow rated based on the maximum flow capability of the filter. The final rating is take when the filter reaches 20-25 inches of water restriction at that flow. A filter could start out at 97 percent initial efficiency and end up at 99.9 percent on the final. The final figure is the one touted during advertising. Typically, by the time the filter has reached 20 percent of its lifetime, efficiency has improve 1-3 percent. This is why changing a filter too early causes more dirt ingestion than changing it a little late. Changing your air filter too often is killing your engine with kindness, more or less. A one percent increase in filtration efficiency is a 50 percent decrease in contaminants passing thru the filter.

I asked why both efficiencies are not commonly listed and the gist of what I was told is that, often, they don't even test it and if they do, it improves so much and so rapidly that it's immaterial.

Bear in mind that any filter will test better, efficiency-wise, on coarse dust vs fine dust. Both types have the same size particles in them, a range from 2-200 , but the percentages of each changes. The fine grade dust has more fines in it, obviously, and fines pass thru any filter more easily.

I interviewed two engineers for a project, both specialists in air filtration, and both said it's best to leave the filter in place rather than constantly molesting it. They especially cautioned against blowing, tapping and attempting to clean them, though they conceded that a careful person could probably get back a few thousand miles of life from a careful cleaning. A big danger is that you will mess up the seals on the filter and when you reinstall the used filter and it won't properly seal the second time around. How likely that is depends on the construction of the seals and that varies considerably by design and the quality of construction. Those engineers, and others besides, recommend using a restriction gauge as the sole arbiter of when it time to change an air filter.

 

[Smokescreen]

The question one has to ask is while the K&N is loading up getting better filtration, does the 'flow performance' benefit over paper still exist...or is it now at the same or lesser value than the paper. For how long does that flow performance advantage apply?

 

[Jim Allen]

Originally Posted By: Smokescreen
The question one has to ask is while the K&N is loading up getting better filtration, does the 'flow performance' benefit over paper still exist...or is it now at the same or lesser value than the paper. For how long does that flow performance advantage apply?


All the way down the line but one of the dangers to oil cotton gauze vs some of the other types is that they do not tolerate high restriction well. At high restriction, dirt can be sucked thru the media but the filter has to be very, very dirty before this happens. This happens to every type of filter to some degree but more so with oil cotton gauze. IIRC, that's by K&N prefers cleaning at a lower restriction level than the point you would replace a paper filter. This is especially important for turbo diesels, which can generate very high airflow. I tested a performance application K&N for a Land Rover back in the '90s that had less restriction with a quarter inch deep dirt cake on it than the OE filter had brand new.

 

[barlowc]

I took a couple more pictures after I cleaned the filter, let it dry, and properly re-oiled it. Looks just like new out of the box.

 

[HTSS_TR]

Looks good.

 

[accent2012]

[censored]. looks brand new from factory.

 

[Scum_Frog]

I have a K&N in my Nitro and I have the same experience as the OP.

 

[skyship]

The good people that built your car with a normal paper filter do know what they were doing and trying to beat them by fitting a different air filter system does not work.
There are lots of UOA results showing how important air filtration is and the only way to prove your new air filter is better would be to keep switching from using one, to using the original unit long enough to get conclusive UOA results.
The oil used for the K&N system can contaminate the MAF sensors on some cars like my Volvo diesel and cause false warnings related to air flow or turbo failure that only a dealer or chap with the code reader and program can reset.

 

[Jim Allen]

Originally Posted By: skyship

The oil used for the K&N system can contaminate the MAF sensors on some cars like my Volvo diesel and cause false warnings related to air flow or turbo failure that only a dealer or chap with the code reader and program can reset.


If you thoroughly read This and follow all the links, you will change your mind. If you've read anything else in this section, you will know I have made a study of air filters and am no proponent of oiled cotton gauze filters, but fair is fair.