K&N filters - icky

First, I want to say hi to every one. I have not visited the 's website for an awfully long time and it is nice to see you have found a nice home. The last time I was around was when we had the ghost on the main page that would not go away.

So, to my subject of K&N filters being icky. This weeked, I removed my cone filter to check it out, see how dirty it was and all. It had been a year since I installed it along with my vacuum gauge to measure head loss (dirty filter gauge). Well, I was pretty shocked to find a layer of find grit on the inside of my home made air tube adaptor and the vacuum gauge had not moved - no head loss.

I wipped out the inside of the air tube and then re-installed the filter and drove for the week, then rechecked it today. Guess what, there was grit on the inside of my adaptor again.

And the past few days I have driven to and from work 5 times and it takes me about 5 minutes to get there, driving on paved roads.

So, to all of you out there who think that you are safe, you are not. Go out and get one of the foam pre-filters before it it to late. I am off to the auto parts store tomorrow morning in search of one. Otherwise, I am putting back in my stock paper filter until I find a better solution.

XJGuy is correct, the K&N's do not protect. Now I have to live with the idea of all that crap that went right into my engine the past year. ;(


Tom R. Dennis

I've been saying this for years. IMHO, K&N's suck for filtering efficiency...look around the web for some of the diesel tests.

I like Wix

hmmmmm I don;t know about that...... I put in my K&N a while a go (the bigger cone went in over a year ago) and I have pulled it twice (once to redo the mountm once to clean the TB) and it looked all good inside: no extra crap, no sand, no discoloration and so on...... I guess it all is also related to how well it;s loaded, cleaned and so on: I heard of someone using a harden hose to clean his whci is a nono as that just kils it.

Kejtar

Filter better or flow more. Choose one.

Ther eis a happy medium out there someplace....

Kejtar

I could not see the fine grit. I took my finger and ran it inside of the tube to see if Icould feel anything - yes, I could. But, no it was not visible to the eye. This stuff was very fine, but was abrasive feeling.

My air tube is a 3 inch stainless steel exhaust adaptor that is about 6 inches long. I drilled and soldered the crank vent nipple to it along with a small nipple for the rubber tubing that goes over to my head loss gauge.

No leaks around the nipples - I used high temp silver solder so the joint is strong.

Bad thing about the whole thing was that I had just freshly spray oiled the filter using the K&N oil after my primary inspection. No wonder the synthetic oil always looked dirty when I went to change it.

Tom

It's still beyond me why you folks would want to suck hot engine bay air anyhow...and "more" of it at that!

Cheap help for K&N cones- a shop vac filter bag.


I've been running it that way for the past 45,000 miles. 140k on the Jeep now and it doesn't burn oil.

TOZOVR said:

It's still beyond me why you folks would want to suck hot engine bay air anyhow...and "more" of it at that!

Click to expand...

http://community.webshots.com/album/33598274mjXQcW

Alex and Chris both pose viable solutions to issues...but why not just run a box?

I'm just playing Devils advocate here...filter/box setups are a personal pref....much like chevy vs ford etc....


RJ

Well there is more then one benefit to the cone...... in the older XJ's the box seemed to have a matching hole in the front grille (matching to the intake that is) while the newer XJ's don't seem to have that: that I think ends up limiting significantly the amount of air coming in...... Also with the cone you end up gaining extra room: I'm looking into sticking the wiper fluid container there as I need it to remove it from the fender.....
Also for extra cleaning.... you can always put on a prefilter of sorts..... they make them for the K&N's
Kejtar

I deal with air filtration on a daily basis...there is a distinct difference between "high performance" and "high efficiency"..a "wetted gause" filter does well to keep alligators and logs out of your engine...at least run a foam prefilter..I'm sticking with pleated paper...and if i ran in a dusty environment, I would run a prefilter on the pleated paper element...the head loss gage is a great idea ...:clap:

If you are interested in the loss of head gauges, do a search for: air filter restriction gauges

Here is a page I found - it is a pdf format.

http://www.fleetguard.com/fleet/pdfs/product_lit/south_pacific_news/3300920A.pdf


The first time I saw one used was on one of our F-250 service trucks. The one I purchased was scaled to 18 inches of vacuum.
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I tried to find the foam pre-filters for my K&N, but none of the ones I looked at would fit. I mine is 5" at the base and 4 5/8" at the top and is 8 inches long.

When I went to choose a cone style filter, I made up a little spread sheet to give me the various surface areas of different diameters and lengths. You entered the bottom diameter, top diameter, and length. It would calculate the area. I still have it if anyone is interested - it is in a ms office xls format.


Tom

I just switched from a flat K&N filter in the box to a large K&N filter and I definetly notice the difference in power above 2K rpm. I noticed no difference switching from paper to K&N in the box. I sitll have to build a heat/mud shield but that will be done soon.

I have used K&N filters on at least 3 different vehicles over the last 15 years and I have never run into any issues that you have discussed? I have had them on off-road and on road vehicles and I have used them in Az (very dusty), CA and WA and they have all worked really well for me. I have also used prefilters on some of the applications but not all of them.

I do like the vac bag idea, very nice!!

Tom, your K&N part number is RE-0910, the filtercharger for you filter is Part number 25-0810. the precharger for your filter is part number RE-0910PK, but it says it is only 7" long?? not shure why??

Michael

A clean paper element filter will flow as much as a clean K&N, and filter much better. K&Ns only have an advantage when comparing a dirty paper filter to a dirty K&N. The K&N has holes so large that even loaded with filth it still flows well, but at the cost of your engine's life. Someone do an oil analysis to once and for all put this to rest.

I have read several real world independent dyno tests using "high performance" air filters, none showed an advantage over a clean paper element, certainly nothing filters better. Want more flow, dont think paper gives you enough? Easy solution, get rid of the air box use a humongous conical paper filter and you will have enough surface area to filter air for a Boeing 747...its what I did in the 89 I used to own.

XJguy

XJguy said:

A clean paper element filter will flow as much as a clean K&N, and filter much better. K&Ns only have an advantage when comparing a dirty paper filter to a dirty K&N. The K&N has holes so large that even loaded with filth it still flows well, but at the cost of your engine's life. Someone do an oil analysis to once and for all put this to rest.

I have read several real world independent dyno tests using "high performance" air filters, none showed an advantage over a clean paper element, certainly nothing filters better. Want more flow, dont think paper gives you enough? Easy solution, get rid of the air box use a humongous conical paper filter and you will have enough surface area to filter air for a Boeing 747...its what I did in the 89 I used to own.

XJguy

Click to expand...

Well said!

If you are interested in prefilters for your K&N or other open element style filter, check out a company called Outerwears. They make prefilters for K&N, but if you call the company direct, they will make any kind of pre-filter you want. Pretty much they'll make anything you want out of their filter material. They even have a specially treated material that repels water but lets air through (This is what I have on my filter. It works OK, but if you submarine the filter, I doubt it would do much good.)

While you guys were posting this earlier I was doing an oil change on my 98 so while I was waiting for the drips to stop I popped my air box. Checked the air tube and ran an old clean bathroom towel thru the tube. How the heck did all that crud get in there. Yea, I run the K&N flat panel and changed it a few days ago but it has not been in there for a few months since the last time I swapped it out to clean and oil it. I have a OEM paper in there and will be keeping an eye on it. Next sat is plugs/wires/cap/rotor/coolant flush and new belt day and I will run another towel thru.
I think I might also duct tape the joint between air box and the air tube, I don't trust that squeeze fitting.

I took off the cone and put back on my old air box and paper filter until I get something better. I like XJGuys idea of the cone paper element and found the elements, but not the container. Anyone have any leads for round filter holder assemblies that have a 3 inch attachment for the duct?

If not, it will be fab time. Use some stainless flat plate with a hole cut out in the middle for the pipe and then run a stud up through the middle and then a large washer over the stud with a wing nut.

I liked the K&N because I could attach it with a hose clamp. I am just not sure that even a foam prefilter is the way to go. However, a foam pre w/o oil over a paper might just be the ticket.

I think the way to go is the corse filter over the fine. The course one catches the bugs and stuff, leaving the paper for the fine particulates.

Tom

My wifes 96 Olds Cutlass has a round can filter element, been a while so I don't remember the size, I'll grab a flashlight and go look....yuppers, looks the same size, maybe a hair bigger.