Hi all,

the addition of my bluefin stage one tune has me curious about air filters now. On my next service I’m thinking of going for one of these over the OEM filter. 

I’ve had a look at their website and seen there are two for the 2015 Focus. One of them says Focus III. 

Any ideas which one I need?

 

Anyone using a K&N? Any thoughts? 

K&N has the K&N E-2993 replacement filter and the K&N E-9289 replacement filter for the Focus MK3/MK3.5.

The K&N E-9289 replacement filter is the same filter that is included in the K&N 57S-4000 kit. Compared to the normal K&N E-2993 replacement filter this filter has a larger filtration surface (a larger amount of lamellas creates a larger filtration surface). Another advantage of this filter is the removable end cap. The filter can both be used with or without the end cap. Removal of the end cap transforms the air filter into a semi open air filter.

The price of the K&N E-2993 and the K&N E-9289 is about the same so personally I would always choose for the K&N E-9289 replacement filter. 

 

I have the K&N E-9289 air filter in combination with the MK3.5 RS air filter housing on my 2013  1.0 ECOboost. In my opinion this is a really nice combination. it also is cheaper than the K&N 57S-4000 kit. I am currently running a slightly modified version of the original MK3.5 140 HP software. Next to this I always use 98 Octane (or higher) fuel.

My 1.0 ECOboost is really quick now. it accelerates a considerably faster than a 1.5 / 1.6 ECOboost 150 HP.  

Is it louder than the original air filter?

The 57S filter is also the one recommended by Mountune for use with the upgraded intake pipework for the ST / RS and in some kits they even supply them with their kits.
You will get a bit more induction sound with the end cap removed.

Sent from my SM-G965F (S9+)

Are they easy to self fit?

Wondering whether to just do it myself it there’s little that can go wrong and it’s an easy job, or wait for the full service later. 

5 minute job.
Usually just a screwdriver or a small socket set needed to remove the airbox lid and old filter out / new filter in.

Sent from my SM-G965F (S9+)

7mm socket. 

7mm socket. 

There you are then [emoji5]
Tbh a decent ratchet screwdriver with some socket bits is good enough, doing it with a ratchet handle can result in overtightening and a split airbox.

Sent from my SM-G965F (S9+)

and you dont want to split your airbox though to much *****. lol 

and you dont want to split your airbox though to much *****. lol 

Trust you [emoji848]

Sent from my SM-G965F (S9+)

22 minutes ago, Stoney871 said:

Trust you

Sent from my SM-G965F (S9+)
 

Yep, you can trust me to lower the tone. Bad me. Lol

I’ve ordered the E9289 filter today. Will be here tomorrow. 

Will this be a standard fit straight in place of my existing filter or does it require other parts?

will fit straight in. did mine this morning.

Any improvement?

nothing noticable yet. 

Should I leave the end bung in or out?

Is it just a noise thing or does it affect performance?

it is completely up to you

The air filter can be used with or without the removable cap. The removable cap both affect noise and performance. However the performance difference will be hardly noriceable on the 1.0 ECOboost.

Without the removable cap the induction noise will be a bit louder. However on the 1.0 ECOboost the turbocharger dampens a lot of the induction noise. Even with the RS air filter housing and without the removable cap the induction noise is still quite sophisticated.

 

I suggest to use the filter with the removable cap installed first and get used to it for a while. After a few weeks remove the cap to experience the difference. Based on your own experiences you can decide whether you prefere to drive with or without the cap.

I’ve fitted it and left the cap off. 

It’s not too loud. Sounds just right. Not really noticeable in terms of people outside the car. 

I’ve noticed the throttle response is certainly better. Even at set off. 

Also just done a motorway run. Sixth gear and pick up to top end speed is very noticeable. 

Overall it’s smoother. But I’m very happy with the bluefin and K&N combo. Massive improvement all round in terms of fun, smoothness and economy.