K&N Air Filters

[Barry Edmunds]

Wanting to touch base with anyone who has used or is currently using K&N style rectangular shape sports air cleaners.

Also interested in experiences with foam versus paper elements.

Barry

[Duk]

Wanting to touch base with anyone who has used or is currently using K&N style rectangular shape sports air cleaners.

Also interested in experiences with foam versus paper elements.

Barry

I've found fine dust inside the inlet plumbing of my MR2 and that uses an oiled foam K&N filter. Admittedly it's in a pretty awful spot, but it should still stop what is getting thru. 

Plain and simple, if there isn't much in the way of pressure drop across a clean factory filter element, then there is ZERO performance potential by putting an after market filter there.

[scott.venables]

Duk, do you mean oiled foam or cotton? 

I have a K&N oiled cotton element (flat panel type). For me it wasn't a performance decision, because the factory element is enormous and wouldn't be a restriction. I did it mainly because the once-use paper elements aren't easy to get and I figured it might save me some money if I keep the car long enough.  The worst part is the initial cost, but given it's the last filter I'll buy for the car, I don't mind too much.

Scott

[Martinsifredi]

Hi there Barry,

I use a K&N flat panel paper filter in my 33 Boxer 16V, the quality is great, the filter seems to fit exactly the same way as the factory filter with no gaps .

One warning , it is important not to clean these elements with high pressure air , regardless of what others say, as some particles can get "pressed" into the filter paper and eventually come through .  As for the dust in the inlet tract , there may have been a slight gap between the sealing surfaces allowing some blow by of fine dust particles. Or the filter is very old and is showing signs of damage to the paper element . 
As with everything , things have to be taken care of in the correct way in order for the product to perform .

Another great filter is BMC from Italy.   www.bmcairfilters.com

Martin

[Barry Edmunds]

Guys, thanks for your input. My major reason for considering this style of air cleaner is for engine bay space limitations and not for performance gains (if any).
I will follow up the BMC option.
Barry

[philpot]

Just out of interest, my spares car had a BMC oiled cotton filter in it. Had to chuck it as the external silicone/poly/rubber frame had disintegrated and perished.

It had no other frame/skeleton to connect the sealing edge/lip to the element itself.

That's one reason I bought a K&N for my 16v.....

[Duk]

Duk, do you mean oiled foam or cotton? 

Oiled cotton.

I had an old HKS mushroom pod filter that came with a half cut I bought and they are scary in how open they are. It was at least a few years old, even still, given what HKS stuff costs, if it degenerated down to what I saw, you'd be pretty pissed off if you pain money for it. If it was like that from new........... 

[philpot]

Hmmmm....

" The last filter you'll ever buy..."

I wonder how many years the definition of "...for the lifetime of the car..." they actually mean?  Maybe thats the consumerist, throw away society 'new car every three years' lifetime....

Looked at the pod style in passing, besides being illegal (would've voided my insurance...ie thats right now) On the 33 16v is sucks air from up the back and up the top of the RHS of the engine bay. The only concession to cold/clean air is a pipe run from behind the front air dam up to vaguely in front of the pod. The sealed standard box with cold air pipe down to behind the bumper seems much more efficient in getting clean, cold air into the engine.

Get back to me in three years or so!

[Darryl]

I stuck a K&N flat cotton filter in the 75 TS for the "last filter you will buy" reason more than anything. It was a marginal call cost/convenience wise but it was there in repco the day I needed a filter.... Given the stock filter is relatively large I wouldn't think there would be any performance gain unless you were comparing to a severely clogged up filter. It filters something (cleaning it you get a fair bit of gritty gunge...) so I'm not too worried about it doing any harm.

[OzMidnight]

MRT Rally site used to have an interesting article on K&N vs oiled foam.  Their result was backed by University testing.  It was a good read.

Here's an excerpt:
Superior Filter Efficiency
Unifilter holds a certificate for both the Korean and Japanese market entry. This certificate allows Unifilter to be used for both defence applications and government transport applications.

Our filter was tested at the Seoul University and was rated at 99.2% efficiency with a micron rating of 1 to 2 micron collection ability. As a comparison - paper filter efficiency rates at approximately 96% and 30 to 35 micron collection.. (This is for original equipment paper air filters - aftermarket would rate no where near this).

You may also care to note a recent K and N advertisement that stated that a foam outer was now available for their filter which improved the K and Ns dust retention by 90% whilst only increased air flow restriction by 2%. This would indicate the Dust Retention of a K and N would be in excess of 100 micron - if the foam cover produces only 2% restriction - why not use a foam filter in the first place.

This above info was taken from the MRT Performance site a few years ago.