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Performance Air Filter


TomsFocus
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Morning,

Just wondering which air filters you guys use?  And where's cheapest to get them lol.

It's coming up to major service time again and I was just going to buy another OE Mahle filter but thinking about Green Cotton or similar...  Don't want an induction kit!

Cheers

Tom

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I use the K&N E-9289 replacement filter which is also included in the K&N 57S 4000 Kit. Compared to the standard K&N replacement filter for the Focus MK2.5 and MK3/MK3.5 (K&N E-2993) this filter has a larger filtering surface and a removeable end cap to convert it into a semi-open air filter. The price difference between these 2 filters is relatively small. I paid under €75,- including P&P for this filter on amazon.

 

 

 

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I use the paper filter if its good for a 350PS RS its good for every Focus using the same filter size/box.

Give this a read:

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

 

You are better off trying to reduce restrictions on the intake and just changing the paper filter every year.

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contentious point to be honest both have negatives and positives paper element will trap more air borne particles but is restrictive as a result the k and n is less restrictive so breathes better but tiny particles will get through a happy medium is a panel filter from k&n in the factory airbox.the induction kit will also do a good job but only if its properly placed and has a heat shield or you start sucking in warm air so its up to you which theres 2 major brands to look at k&n or green filters avoid the foam filters

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Well that's a nice unanimous vote then... :laugh: 

I don't want induction kits, been there, done that lol, don't like them on diesels.  So need a replacement cylinder for the airbox ideally.  I've recently preferred foam filters as there's no oil to ruin the MAF, but places like RAMAir and PiperX don't seem to do replacement OE ones. 

Green cotton is what I want to try I think, it's the only one I haven't tried so far lol!  Wondering if I can get one for the Focus and one for GTi6 with a bit of discount for buying 2...  Any good suppliers or just go through eBay?

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13 hours ago, alexp999 said:

I use the paper filter if its good for a 350PS RS its good for every Focus using the same filter size/box.

Give this a read:

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

 

You are better off trying to reduce restrictions on the intake and just changing the paper filter every year.

I agree with this, the air filter isn't usually the issue, its more about the intake system and other restrictions.

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I should've made it clear in the first post.  I'm not looking for more power lol, I can categorically say it doesn't make any difference through dyno tests lol.

Just want something that doesn't need replacing every 6 months and a bit more induction noise would be nice (well, what little extra you get with the ducting in place).  Do get a bit more with a new filter but it doesn't last long at all.  And the filter seems to be pretty clogged before I've even hit 12k on it, starting to wonder if it's that hampering my MPG recently.

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If you need to change the filter every 6 months you'll probably need to clean an aftermarket one even more. They have a lower filtering capacity and an exponential increase in "clogging" due to significantly less surface area. It's in the link I posted.

Reducing intake restrictions can still help with responsiveness. Also noise depending on the model, like the mk2/2.5 snorkel.

I'd be looking at an ST airbox to add an extra intake pipe to the box if it was me.

That said everyone has their opinion on this. But I'd wager you only notice the difference with an aftermarket filter when it very first goes in due to it being completely clean. Reducing restrictions should be a permanent benefit.

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just chuck in another mahle filter or the like, where are you driving to get your filter blocked up so quick? ùnder normal operating conditions a standard filter should be good for at least 30k minimum without serious performace loss.


i had a car with the same air filter from new to 105k, just occasionanly blew it out with compressed air, no noticable loss of power or fuel consumption, engine was good as new, bit extreme i know but shows filter was still performing its job .
im not saying do the same. lol
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the thing I like about the green cotton filter is that I haven't had to replace it at all, with the millage I do I'm changing the filter several times a year, after July the savings ive made have paid for the filter.  in saying that, I'm not sure id bother if I got a new car, but fo now I might consider getting one of the ones with the hole in the end or I might just do a mod on the airbox for a bit more noise.

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2 hours ago, iantt said:

just chuck in another mahle filter or the like, where are you driving to get your filter blocked up so quick? ùnder normal operating conditions a standard filter should be good for at least 30k minimum without serious performace loss.


i had a car with the same air filter from new to 105k, just occasionanly blew it out with compressed air, no noticable loss of power or fuel consumption, engine was good as new, bit extreme i know but shows filter was still performing its job .
im not saying do the same. lol

I drive a lot of rural farm tracks, dust everywhere. :sad: Maybe it's just my imagination that its clogging the filter though. :laugh: 

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I just use the original OEM filter and replace it every year when I do the service. Maybe a few times throughout the year when I am giving the car the usual checks the car I will give it a blow out and the air box with compressed air like Iantt does. I was always wondering if I changed to filter would I get a bit better acceleration and as its is my car sometimes feels restricted when I accelerate I have the more I have the accelerator to the floor the longer it takes to pick up but is I only lightly press accelerator maybe 1/4 way down and hold it the car seems to pick up better. I always wondered was it down to a little air restriction or so,..........? All else seems to be fine

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I use a Green Cotton air filter in my

MK3 Focus. Had one on the MK2 as well. Its the direct replacement panel filter. Pretty good, gives a slightly more noticeable throaty sound to my MK3 and acceleration is a slight more responsive. I think it cost around £60 delivered.

Sent from the pub with a pint in the other hand.

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So, I've decided to stick with OE air filter this time after all lol. :laugh:

I'm also going to leave the fuel filter for now, that alone costs more than all the other stuff even on trade!  If it starts hesitating or jerking I'll change it.  Is it worth draining at the service though?  Likely to be any water in there?  I usually just change them but not at the price of these ones lol.

Also, MPG is still terrible, only really done 'long' drives in it, filled with Shell this time, admittedly half hour was through town traffic, but its getting towards 200 miles and only 53mpg on the trip computer.  Something must be wrong here surely?  Weather is warming up but not warm enough for air con so it's not that either.  I'm really at a loss why it won't do 60mpg on motorway cruises.

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My first filter change after an unknown amount of time had quite a bit of water in it, maybe nearly a 1/3, ive been doing it every 10-12k and there hasn't been much since then.  Course my last filter only lasted for 4k so you never know how long it will last.

 

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Yeah I can only assume you got a bad batch of fuel or a dodgy filter tbh!  This one is genuine Ford and has 'only' done about 12k so hoping it'll last a bit longer, don't want to mess around with it though so if there's unlikely to be much water in it I probably won't bother draining it. 

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