K&N or paper?

[poorshe911]

I have a K&N air filter but am not sure about it's filtration capabilities as compared to the original paper filters, that I went back to using.
I've looked for previous threads on this but didn't see any.
I'm going through a rebuild on my 3.0 over the winter and come spring, I want to get my motor refresh off to the correct start.
Is the increased air flow with the K&N really helping performance but putting more dirt into the engine?
Stay with the paper?
Extra holes in the filter cover?

What do you guy's think?

Thanks,
Michael
Webster, NY
1983 SC - SSI's, euro fuel dist, soon to have 964 cams. I'll post pictures of the engine before/after in the spring. Also removing the big tea tray tail and going tail-less.

[Brad394]

Well most will say stay with paper - it does filter better -

[nesslar]

I say stick with factory orig.

[Milo2361]

I swapped to a K&N (despite others warnings). before the K&N the inside of the airbox(just past the filter) would have a light coating of dust on it. post K&N install it's been completely clean. directions say clean and re-oil every 50k miles, I'm cleaning around every 20k or so to be on the safe side. Works great for me.

[mystro]

Factory/paper is my choice.

[Nick Triesch]

I wonder if there has been a study done? A lot of race folks use K&N.

[poorshe911]

I've been looking for some kind of study but couldn't find one.
I saw an article, I think on this forum, about people cutting holes in their filter covers and saw a difference on a dyno. Don't know if it was with a K&N or paper though.
Anyways, I wonder if anyone has used a K&N for a long period and has gone through the air system during a rebuild or etc and found any issues.

I've used the paper filter the last couple seasons and the car ran very well .. didn't detect much difference. Doing a rebuild and getting everything squeaky clean along with the cams change I thought I'd get the most I can out of the air intake system and actually now see a performance increase.

Milo,
That's interesting. I never would have thought that to be the case. Does it run better?

[pwd72s]

Originally Posted by Nick Triesch

I wonder if there has been a study done? A lot of race folks use K&N.

Bruce Anderson did a piece in a long ago EXCELLENCE. His conclusion was that paper was better...

[brads911sc]

the reason that many of us use KN is that they dont make a paper filter to work with Webers, PMO's (carbs or EFI) and other brands of ITB's that are sized like a weber KN filter.
I would switch to a paper filter if I could. Dont drink the koolaide. For a a stock car, paper is better.

[Milo2361]

Originally Posted by poorshe911

Milo,
That's interesting. I never would have thought that to be the case. Does it run better?

I really didn't notice a performance difference when I switched. it sounded a little more free back there, like it was sucking in air a little harder but that's about it. my oil wasn't as black during oil changes (been using same brand since I bought the car). If there is any performance gain I suspect it would be quite minimal.

[80-911SC]

MAHLE ...

The only word you need for filters .. air and oil

IMO .. and others smarter than i am

[RoninLB]

Originally Posted by Nick Triesch

I wonder if there has been a study done? A lot of race folks use K&N.

from what I've read the majority of tests are done in house on a bench with varying amounts of dirt in the air stream. Under these test conditions paper wins

Then I read a test where the author says an operating engine is necessary to shake up the oil in KN so it turns to finer mist particles to provide proper filtering. His conclusion that over the longer term of say 20k miles the KN was more efficient


You can draw your own conclusions. Clean the air box and just wipe the inside of the air chamber with a clean white paper towel after 10k miles and see what you come up with

personally...... paper is brainless and Mahle is quality. I always used grease around the sealing rubber of the paper filters.

I'm using KN now and keep it oiled. I don't even strip old dirt off with the KN filter cleaner. Also same routine for the grease on the rubber sealing ends. I've run KN for a quick 10k, 15k, and 20k miles which included relatively high levels of dirt roads and have no complaints with KN

[DRACO A5OG]

Originally Posted by poorshe911

Is the increased air flow with the K&N really helping performance but putting more dirt into the engine?
Stay with the paper?
Extra holes in the filter cover?

Performance? Well MPG will go up due to less air restriction, maybe better top end.

Dirt? Yes, you will introduce dirt into you newly built engine.

Paper? If you want a cleaner oil change & less dirt in the engine, I 'd say Yes.

Holes? In your year, holes may not be a good idea on the cover, if you are in a rainy climate, the box will suck water in directly. On a 3.2 the chances are less due to the side position of the air box.

I reverted back to paper from a inverted K&N cone filter and now very happy with my oil changes.

[zotman72]

We dynoed KN vs Stock paper on 3.0 SC Euro PCA Club race car a couple years back, no improvement at all over the stock filter. YMMV

[Steve@Rennsport]

OEM paper is the ticket for street cars with the exception where there is no alternative (carbs).

Leave the K&N's, ITG's and such for race cars.

We see the differences in oil analysis (higher Si levels) and cylinder wear.

[RWebb]

Originally Posted by DRACO A5OG

Performance? Well MPG will go up due to less air restriction, maybe better top end.

This will happen ONLY if mpg (i.e. air flow) is limited by the filter itself, and not by anoy other factor.


Just read the above post...

[porterdog]

Originally Posted by Milo2361

I'm cleaning around every 20k or so to be on the safe side.

The dirtier they are the better they work; 50k is safer than 20k.

[ivangene]

Originally Posted by porterdog

the dirtier they are the better they work; 50k is safer than 20k.

+1

[ant7]

hi all,
well, i have experience with K&n filters in my high [ish] mileage BMW 318TI, its now covered nearly 180,000 miles, its totaly original, dosent use any oil between service intervals, and the exhaust runs so clean that you would be hard pushed to get your fingers dirty on inspection, also it frequently surprises the MOT inspectors when they see the emisions readout, the filter has never been cleaned properly since being installed apart from the odd brisk blow out with compressed air. I must add that the filter currently fitted has now covered 90,000 miles.
Anthony.

[wildcat077]

I've been using a K&N filter/plenum system since new on my F150 which now has 240,000 kms and i haul the ATV's and the boat on dirt roads and i've always used Ford FL820S filters and nothing else than Castrol GTX oil and my engine doesn't use any excessive oil or show signs of wear ,although i switched to two stage foam filters in the ATV's and dirt bikes after running K&N's for many years.Wish ProDesign would make them for cars as well !

I recently wiped down my AFM and throttle body and they were both found to be clean ...
I use the K&N square filter along with the Fabspeed air filter box in my Porsche and with the proper maintenance i don't see any problems!

Cheers !
Phil