Good, Bad & Ugly Air Filters and Induction Kits
 

Hi guys, hope all is well!

Currently doing some research on modifications for my Impreza WRX GDA 2.0 MY05.

I'm wondering what experiences and thoughts you guys have about certain brands / models.

I've been looking at these brands:

• HKS Super Panel Filter
• K&N Panel Filter
• K&N 57i Impreza Induction Kit
• K&N Apollo Cold Air Impreza Induction System
• K&N Typhoon Enclosed Impreza Induction Kit
• HKS Super Power Flow
• HKS Racing Suction Impreza Induction Kit
• Mishimoto MMAI-WRX-01P

What are you guys thoughts?

from what ive gathered on this forum is......

stay away from the hks mushroom induction kit

any decent panel filter will be ok

if you must have an induction kit then stick with either k&n, rcm, perrin or aps

i wouldnt have any mishimoto part on my car even if it was free...............

I picked up the Perrin Black CAI from scoobyclinic when they were clearing stock. got a steak at £200 as they are normally £300. Quality is very good although still not fitted as waiting to get it powdercoated

I installed a cosworth short ram high flow kit on my 05 blobeye and saw gains of 15bhp along with an upgrade from 2.5 to 3" centre section. slight improvement in throttle response although that will be down to the map tweak from Andy forrest. Sounds ****in brilliant though
https://cimg8.ibsrv.net/gimg/www.sco...7a3004101e.jpg

ah yes i forgot about the cosworth one, another quality item.

I also have the perrin one can't fault it. Makes a hell of a nice noise

I'm a big fan of the rcm induction kits, developed specifically for the Impreza and gives an awesome whooshing sound when on boost

Can the same be said for the cosworth one?

https://cimg5.ibsrv.net/gimg/www.sco...666a65f6d0.jpg
Been running RCM induction kit on most of my cars for donkeys years now...their "QUALITY":thumb:.SJ.

good lad :)

Does the rcm kit still use a K&N cone filter?

Yes

Does that mean it's a perishable item? ie you'll need to maintain or change the filter at some point throughout it's shelf life ?

Yes. You can buy a k+n filter cleaner kit that comes with a cleaner and new oil.
​​​​​Any filter will need cleaning as part of regular maintenance.When the time comes I'm going to buy a second filter so I can just swap it then clean the one I took off

It's not on this list, but I opted for the Japspeed piece on my Hawk STi in end. After a good amount of research I couldn't really see the reason for the price of the other options. You can use some K&N oil on it, should you want to it doesn't need it, or even replace their cone filter with another piece (K&N cones are ~£30 on ebay).

I can't really quantify the hp increase (as I road tune the car myself), but I definitely did see an increase in air flow at the top end, more air = more power - but really it's about the noise :D

So in summary you could buy the following and save a fortune:

- japspeed induction kit for the pipework only (if really bothered throw away their filter), from ebay
- K&N cone + oil, from ebay

worth considering I'd say. Or just stick to the japspeed cone as I have, and save even more!

Using an oil based filter will wreck your maf. I have a uprated air filter on mine.

is it only induction kits using the K&N that are oiled?

Thinking about getting the Cosworth one when I do a remap.

Get an AEM Dryflow filter. No need to use oiled filters.

No some panel filters are oiled aswell.

To be fair I've been using K&N oiled panel filters for years on Subaru's and haven't had a maf issue to date, but have heard excessive oil can do this. You can clean and re-oil the K&N filters yourself with K&N cleaning and re-oiling kits. Maybe the damage reported is when someone over-oils them?

Do luck filters come out good on dyno tests but are drenched in oil.

https://www.scoobynet.com/general-te...s-morning.html

Have you ever looked at a Do Luck filter? I bought one year's ago based on the dyno results, but they really are poorly made. They only made good results because they were less restrictive and letting more harmful particles through.

Honestly, they are quite poor. I threw mine in the bin and have used either K&N or Cosworth ever since.

Agreed that this is the likely cause. Certainly that's what happened to me when I ran a k&n oiled panel filter! :rolleyes:

However you can clean the MAF with switch cleaner if it does happen.

have always found the main issue is with FOAM oiled filters........the likes of K&N cotton gauze type, when correctly oiled, are no problem

Yes and didn't even remove from packaging just got rid when I saw the amount of oil it was soaked in.