I bought a K&N air filter

It’s an American made filter that fits in the standard XJ6 housing. I got a deal: discount and free shipping. It has affected the tune a little - supposed to breathe better than paper. Anyone have any experience with these: purple cotton media that you can clean and oil? Guaranteed for one million miles/life of the car. Paul

I’ve used them on other cars, and have them on my XJS V12.

Never really notice any better air flow, but they are nice and sturdy and look nice. I cleaned and reoiled mine every 20000 miles or so, depending.

I did have an issue with one I believe messing up my MAF sensor. K&N swear the oil doesn’t hurt them, many people say it does, or it could have been me over-oiling it. But I only use them on non-MAF cars now. My newer cars, you can find similar that aren’t oiled.

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No problem with either my previous XJ40 or with the current XJR.

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Here’s what I’ve been told:. With oil try do a good job of filtering, but are just as restrictive as cheaper filters. Dry, less restrictive, but less filtering. This was based on test data not opinion,

My opinion is restriction only effects peak HP. I don’t drive my street cars at peak HP often. Don’t worry about restriction, go for longevity.

BOBISTHEOILGUY.com did an exhaustive test: it’s essentially snake oil.

I have personally seen, on numerous engines, the amount of fine grit that gets past a K&N. On a race car, where I did worry about peak hp, sure. I’ll be rebuilding the engine every year.

On a street car, there is bupkus power gain.

Rant off…:smirk:

For a street car, it’s fine. Instead of replacing the paper filter every few years, you’ll be washing and reoiling your K&N. It will eventually pay for itself.

I personally just like the look over a wad of folded paper :wink:

Thank you guys, have never had one before. It cost me about the same as two standard filters, I think our supplier might have been running down stock. I will see how it goes. I see XKs has something similar for and E type - will keep my powder dry. Paul

Tons of pro and con on this item.

My lump runs one. Actually a “knock off”. I run it dry.
I just came across it whole seeking to solve how to filter in cramped space. No room for the donor car’s large air box. It did get 'dirty". Evidence to me that it catches dirt!!! Washed it in warm water and soap and good to go again… As I used no oil, no opinion as to the MAF…

For street. use, it is fine. Not needing to replace it from time to time is the value to me.

if I lived in a “dust bowl” like where I was born and raised, I’d think differently…,


question? how long could we street drive before it could actually hurt the engine, or really lose any power that could be measured?
my motor home has 60K miles on a K&N and still runs great!, never been cleaned , altho i check it before any long trips, so far where its mounted(up high) seems OK!
also got two K&N on v12 Jag , oiled and never touched since, low miles tho(10K)!

when i was in engine business doin offroad stuff industrial equipment , they could really clog up quick , black smoke idling, change filters every week sometimes, so modify the filter systems , by adding a LARGE air cleaner cannister , with rotating air flow, and a cartridge the size of a 20 gallon drum!
hows this for some guys , they just took the cartridge out of housing and run no filter AT ALL!
scrubbed out the liners,rings and pistons in a couple weeks!

My history with K&N filters.
Lets just say I"m closer to a dirt nap than when this existence was thrusted upon me.

I’ve put K&N filters in all of my cars. I could go on ad nauseam about K&N Filters, but I won’t.

  • eco friendly - reusable
  • Do enhance the sucking sound of an engine
  • Depending on demographic do last longer than a paper filter
  • good airflow


  • I’ve found two are required per car. One clean and ready to go and the other to be cleaned an not ready to go for days.
  • You have to clean them.
  • That sucking sound is the money sucked out of your pocket upon purchase of the K&N filter and cleaning kit
  • For a Fuel Injected engine oiling is a tricky business.
    • Too much oil will end up coating the inside of the intake & related bits with a light coat of sticky oil. Bits like a Mass Air Flow Sensor. I’ve learned this is a bad thing. because it provides a false reading with an end result of improper stoichiometry (fuel to air ratio)
    • Not enough oil, and the filters performance is compromised, and it’s a bitch to get the particulates out of the cotton filter material.
  • Performance doesn’t warrant the cost. A clean air filter delivers the same level of performance as a K&N

K&N cold air induction kits.
Short version - On the cars I’ve ran them on 96 Impala SS, 88 Gen 3 IROC Z/28. big mistake. No performance benefit except for the Cool K&N sticker. Seriously upsetting part about the kit is it required cutting a hole on the car, that I can’t easily put back. :frowning_face:

I’ve replaced all of my K&N filters with quality 3rd part or OE filters.

This kid does thorough tests. I like the way he thinks.
Filter Test - K&N vs Clean vs Dirty

Ang: I forgot about that effect! I think none other than @Ray_Livingston noticed how stickers help the XK engine.


Almost as good as the performance effects of the Boeing Blade©.

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Damn, I didn’t set a sticker. Bar fridge in the garage is miffed. Paul

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