just bought the car and looks as though it was last changed 14k ago looking at receipts .
what are the reccomended intervals ?

 

every year/service I would... not major money is it?

 

im just debating whether to put a k and n or green one on but bit skint.
just had the old one off and it is pretty dirty .

would it affect the running of the car much as its dirty ?

 

Every 2 years or 20k i think, check every 10k though if you wish

Tony

 

cheers ,probs been asked a million times but are the cosworth one disposable ?

 

Having an air filter is always a trade off between safe filtering v's free flowing properties...

any dirt in the filter will effect performance/fuel economy to a degree

Yes the Cosworth panels are throw away units, not oiled like the K and N's

I run a cosworth panel an it's great (half the depth of the OEM unit)

 

Yes they are a service item so throw away.

Tony

 

thatl be why there cheaper then .so it wouldnt last any longer than the oem ?
il not go on as i know theres loads of threads on this but is there any difference in engine note by adding an aftermarket one?

 

You can get a slight change of engine note, my STI panel filter seems to give more of a roar higher up the rev range now but costs a little more than the cosworth one

Tony

 

The Cosworth panel in mine gives a kind of hiss when on WOT

and £35 for 12 months use aint that bad! Plus it's a far superior filter to the OEM one

 

im presuming the sti one is just what would be in a sti ?

 

Not necessarily

STI filter's are an aftermarket panel bought from STI Japan and are not standard equipment for UK cars. They're not cheap either, The last one I purchased was £60 back in 2004 for my then newage STI.

You can tell by looking at it, the STI one will be red/pink in colour and maybe have STI written on them...they also have a s/steel mesh covering iirc?

 

If a paper filter, check it every 10k miles and blow it from the inside out (i.e. from the clean side blow air towards the dirty side).
Subaru service schedule is 2 years/30k miles whichever comes first IIRC.