Filter Q

[BRUN]

been wondering today, some of the cotton gauze performance filters advertise the fact they have a larger surface area over the foam counterparts, however looking at some OE filters today, they have much deeper filter pleats than any K&N or Green ive ever seen

so, how much better are performance filters ?

a new filter for a valver / willy from Renault is only £13.27

[arj256]

I personally now use the standard filter.
As you can change it regulary.
You cant easily clean the aftermarket ones, and foam you just end up digging the dirt deeper into it.

And i didnt notice any difference between the two, so i know what im sticking with.

[BRUN]

anyone else ?

[drsmith1979]

a friend of mine was a air flow engineer for british aerospace and he did a lot of research on his car of choice..... Mitsubishi Evo, where tuning parts cost a small fortune.

He found that foam filters perform better than cotton or paper when they are moderately dirty as they filter the air superbly and have a good flow rate. however, if you let them get too dirty what happens is they cause too much resistance and a 'suction' effect occurs and the foam bulges up and expands, as it does so all the particles trapped in it are released into the inlet manifold and subsequently the engine! err not good lol

Cotton gauze filters perform best when clean and do have a great flow rate over paper and foam when new and/or clean. the problems with cotton is that depending on the power of the engine they are designed for, they can be quite bad at filtering the air particles, but generally, when kept clean and in good shape they are a good cheap alternative.

The surface area scenario is a bit of a misnomer really, as paper filters technically have a larger surface area as their pleats are deeper and have more of them. It relates to its air flow and cleaning ability per cm squared or something... so a smaller surface area of cotton gauze with oil and designed properly acts like a much greater 'standard surface area' if that makes sense? thus their claims.

I had a k&n replacement panel filter on my Evo and it was mintarooney, cleaned it every 6000miles or so as i live down country lanes and it breathed better and revved easier too.

conversely, all the trucks i have tuned and worked on in the USA dont like K&N as they say they dont filter too well, this goes back to the engine power, some of the v8's have ridiculous amounts of power and torque and move the filter around which causes damage and can force particles through the gauze.... alot of expensive kits have a paper filter! lol

so the decision is yours... personally on my willy 3 i have a brand new foam filter as part of my hill power shielded induction kit. it performs extremely well and is more than upto the job. requires less cleaning too, you just have to makesure it doesnt dry out and doesnt get clogged.

that any help?

[MAXIBOY]

and more so does your engine need more air than the original filter can supply. a lot of early carb and injection systems used to have very badly designed air filter housings drawing warm air and tiny intakes.
early minis etc where crap and a performance system made a great big improvement. but newer systems are much better designed so theres less gains to be had on newer cars.

with the clio there are improvement possible but you need to decide the standard of tune and every last bhp you need to tune. scuttle kits work well but if you will see a discernible gain between one well maintained element and another in the same airbox i would be very surprised on a standard engine.

[BRUN]

well i do have fast road cams and a chip so i probably do need the extra air

maybe ill stick with the ITG's, they are cheaper than all the others anyway so i usually just replace it

[kj16v]

a friend of mine was a air flow engineer for british aerospace and he did a lot of research on his car of choice.....

An air filter post based on fact for a change! Nice one!

[Rob72]

clean a foam filter with hot soapy water, you can even soak it with filter tack so none dust or shite gets near the t/b if you rally yer car along dirt tracks.