Feb 25, 2010
Just wonderin if anybody knows how to clean it without using the cleaning stuff you buy from k&n???
Cant you just wash it in soapy water?
I used soapy water with Cilit bang on my open cone and it came up gleaming, Made sure i rinced it Vwell though!
I was wondering. How restrictive are the standard panel filters? would you recommend a performance panel filter? If so which is best?
It is my belief (not proved) that a standard filter will flow well enough for a standard s3/a3. And anyone who buys one has fallen for K&Ns con.
My mates cossie (350bhp) ran fine on a ripspeed cone filter lol
some people just get anal about it
Ive got a 1.8t (150bhp) and its remaped, so would it be an idea to get one?
not if its 10x the price
so are you saying its not worth it then?
However, you can maintain a replacement panel filter to outlast the oem paper type.
OEM filter around £10,
K+N arond £50? so if it lasts 5 services, its not cost any extra.
yeah definately not worth it
yeah thats true. But is that the only benefit then?
id rather buy 5 paper filters. Costs loads for the cleaning shiz and oil
Cleaning your cotton filter - one way of doing it!
I had this problem recently. You can use a soft paint brush to gently brush off loose debris but most of the dirt is well and truly lodged tight in the matrix and held by the sticky oil. That's when you need the proper cleaning agent.
The old cleaning stuff from K&N was a solvent that did a really good job and turned the filter near white again, blasting out nearly all the rubbish. Their new cleaning agent appears to be a detergent dispensed via a weak hand operated pump. Letting the solution soak in and then rinsing under a tap, as instructed, removed some dirt but still left the filter impregnated with the red dyed oil and much of the dirt, including organic debris, e.g. seeds, tiny twigs, insect parts etc. I wasn't impressed. I gave it a second washing but ran out of detergent and it was still a red and dirty black colour. How useful would the red dye in the new oil be for evenly applying the oil when the filter was such a dirty colour? Every time I slapped the filter down onto a flat surface more debris came out! What to do now?
The K&N instructions warn against using solvents which can soften the foam rubber and shrink the cotton. They warn against using a compressed air line which can blast the cotton through the wire mesh. Using a stiffer brush can poke holes in the cotton too. Options seemed limited.
At this stage my filter was in such a poor state that I would not want to put it back in the car. I spoke to Awesome GTI about this and they recommended simply replacing the filter - for all the trouble cleaning it entails. Perhaps they had a point?
Undefeated, I set out to give it a better clean and also investigate some accusations thrown at the cotton filter idea - namely that if you hold the filter up to a strong light you can see holes through it - so how can it be that good at filtering? Would you be better off with a paper one changed more frequently to keep up the flow? As a filter they do flow better but restrictions also depend on your airbox etc.
DISCLAIMER: What Im about to show you comes with no guarantee. Manufacturers guarantees will be invalidated and all Im telling you is what I did as an experiment. You repeat the same thing AT YOUR OWN RISK. If you try this I would advise close scrutiny of the filter after treatment with a microscope, comparison with a new filter and careful inspection of installation and subsequent adequate checking. IF in doubt buy a new filter rather than risk your engine especially if you drive in a dusty sandy environment.
I came up with the following logic: Cotton is used in clothing and does seem to lose its softness with frequent washing but you can soften cotton fabric with fabric conditioner. Agitation in hot soapy water seems to work for clothes so why not for the filter? At this stage I had nothing to lose. The dirty filter was either going in the bin or
. You can probably guess whats coming next.
Yes, a Creda 1200 Cascade automatic washing machine with the normal addition of washing detergent and fabric conditioner! The idea being that the sustained hot agitated washing action would do a far better job than a quick rinse under the tap and the fabric conditioner would fluff up the fibres, avoid any shrinkage and close up any holes in the weave. My only worry was the rubber but this seemed to be a one piece injection moulded process so there was no glue to come apart.
The filter fitted nicely in between the drum features, so did not rattle about in the drum. The water merely washed over it. As you can see in the following picture the filter is pretty clean after emerging after the spin cycle.
The following view is what you get when you hold the filter up to the light. Lots of bright holes or are they? A new one does this too. Clearly more light gets through in between the weave and in some places more than others.
The following views are taken with a x50 microscope. You can see that most of these apparent holes are still criss-crossed by fibres.
There are not really any straight through unrestricted holes but a labyrinth of random fibres with more than one layer of cloth weave. Thats the idea of these filters the smaller and lighter air molecules can rattle through the labyrinth but the larger heavier particles of dirt cant make the turns and instead hit the sides and get trapped in the oil surface tension on the fibres.
Unlike a paper filter reliant on holes small enough to stop the dirt passing through, which then once theyve trapped the dirt become plugged, the labyrinth filter keeps a clear path through. Eventually the passage walls close in but that takes a lot longer to happen.
Oiling the Filter:
With the filter a near white colour its easy to see where youve sprayed the oil so it can be applied evenly. Using some paper kitchen roll pressed in between the ridges and then wiped along; excess oil hanging on the wire gauze can be removed. This should reduce the risk of oil being liberated into the airflow and ending up on your MAF.
Comparing the renovated filter with a new one I could see no discernable difference. Fitting the filter back in the air box seemed to be just as tight as before with no gaps around the seal. As a personal decision (which you may not agree with or want to try), I decided that the filter was good enough for service.
As a precaution Ive smeared some of the clean side of the air box with a little grease the idea being to trap any dirt that gets past the filter. Ill inspect it after a few miles as a final check by wiping off the grease with clean white kitchen roll. Any dirt should easily show up.
I've seen live airflow tests performed on K&N filters and they do flow better than an equivalent sized paper filter and don't clog as easily. Whether they filter as well is another issue but having run cars to over 200k miles on K&N I don't think this is an issue. Don't expect big power gains however just small ones if at all.
The autor or this forum cannot be held responsible for any loss, injury or damage caused by following any of the advice given. Information and advice is given in good faith. Always independently verify information is correct before relying on it.
Cheerz for that detailed guide to cleaning the air filter John-h.
bin it and put a proper paper filter in
+1 for the replacement bosche paper filter... £5 at euro car parts. I nearly changed to K&N. But thanks to the good folks here I DIDN'T. I spent the money on slow cars and fast women, I must say, never looked back since... Heck I may even change it again in a few months. Money you save in the short term is very handy.
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