Hi all,
After your opinions on which filter is best for my scoob.
I haven't had a scoob for a while BUT I'm happy to say I've just taken ownership of Scoob no.9 .. a Hawkeye WRX Wagon with PPP .. this is her


She drives really well , running her on Tescos Momentum , and a few mods lined up like mudflaps and possibly springs ,but feel justnow she would do better if I changed the panel filter.
It's either going to be a Cosworth or Pipercross .. or more odd choices Simota or Do-Luck from Scoobyworld.
What's anyone's opinion on this?
Anyway hope I can contribute to the forums and glad to be back

Edited to say I did search and couldn't see a similar post , and apologies if this is in the wrong section , thought General would get a wider audience.
Regards,
Steve

 

i looked at the do luck one as it gives the best power in tests i found, but someone mentioned that it may not be the best at filtering which put me off slightly so ended up with a k+n which has seemed pritty good, people say about the oil getting on the MAF but ive been okay so far.

Also the cosworth isnt re useable i dont think so at 45+v quid a pop could get a bit expensive.

But i think performance wise they're all pritty simular just depends what you want to pay

 

Green

 

K & N ,personally been using these since 1985,up to present day.Bought well over 30 in that time and never had any problems.I have reoiled my panel filter in my impreza twice in the last 2 yrs and still on the same maf,and my car is a 99/00 which apparently has the chocolate maf

 

+1 for k+n, also if your car is ppp wouldn't it already have a k+n in it, or am i mistaken!

 

Cosworth in both of mine....

 

Can't say it's a recommendation as I've not noticed a difference other than it is re-usable but I have a Simota filter.

 

Typing in 'after market air filter' brings up quite a few results in the search bar. There is some argument that the stock filter is the best one to use (especially PPP cars).

For example, one thread from the search results https://www.scoobynet.com/general-te...el-filter.html

 

K&N, Green or cosworth seem to be 3 of the most popular. I personally had cosworth in mine before changing to an induction kit and never had any problems with it and gave good results.

 

Thanks everyone for your replies.. Just noticed the range of Pro R ones by Pipercross ...hmmm.
WRXroudy ..I promise I did search ! I hear what ur saying re maybe I shouldnt fit 1.. I just believe the car might benefit from better breathing..plus it sounds better too
Might try and see how I get on with 1..and I'll switch back if I see any negative effects .

 

I never heard of a pannel filter making a difference noise? An induction kit on the other hand will.

 

I,ve used K+N panel filters on my last 5 Scoobs with no probs although I,m now using a Typhoon induction kit on my current 05 Jdm Sti which was remapped for it. Would recommend K+N. Steve.

 

You are mistaken

 

I have a Simota in mine, seems ok and managed 305 on the rollers!

 

I definitely noticed a difference in sound when I had the Simota fitted. It wasn't a great difference, but a difference nevertheless.

 

STI panel filter.

 

I've had an STi panel filter in the past and I've now got a Green cotton panel filter fitted.

Can't say I noticed any real difference between the two.

If I'm really honest, I'm not sure I really noticed much difference from the original Subaru paper filter!

 

I've got a brand new ITG three layer foam air filter for the late scooby. I bought it for my STi Hawkeye, but i'm a stickler for keeping it original, and so in the end I decided to use only genuine STi filters.

Open to sensible offers on the ITG, but it's in my opinion one of the best air filters on the market.

Many of the gauze air filters, such as K&N, Green, etc, when you hold them up to the light, you can see some pretty big holes in them, so there is no way these are going to give you any kind of good quality filtration.

A good air filter should, primarily be able to remove particulates from the air, whilst causing minimal losses to the air flow across the element. A thin filter like a K&N, will when clean, not give a very high level of particulate filtration, and will actually become more efficient at filtering as the holes in the gauze start to blind. The downside to this is of course that a blinding filter will inhibit its ability to flow adequate volumes of air through it, which is especially critical at higher engine speeds/loads.

A good quality foam air filter on the other hand, will have two or three differing layers of foam, each of a different pitch. A coarse layer to capture the biggest particles, going through to a very fine layer at the top, where the clean air is drawn through. These filters will be deeper than a gauze type filter, due to the foam make up, but that means there is a much greater filtration area, and so service intervals will be greatly extended.

ITG use a very sticky oil, made by Silkolene, which will not migrate with high air flow, unlike the thinner oils used by K&N etc.

Just take a look at motorsport, and which teams use which filters? Chances are you'll only find K&N fitted to circuit race cars (american ones at that!), as these race engines will be rebuilt at least once every season, and so the teams can afford for a small amount of dirt to get through, in a compromise to reduce the differential pressure drop across the filter.

Now look who uses foam filters, especially ITG!

This is a subject I have spent hundreds of hours studying, as I specialise in the off road (land rover) market.

 

If a K+N panel filter is good enough for a 400 BHP Litchfield car with OE Airbox and TMIC then I think it's a good option.

 

I use an ITG filter too.

 

Green +1

 

I think your missing the point I'm making. Never mind about 400bhp... I'm sure the car would make that with any performance air filter. My point is the job the filter has to do, which is to filter to a high quality, not just let more air through!

Grab a K&N, Green, or any other pleated 'performance' air filter, hold it up to the light, and you can see some pretty big holes in the gauze. Just remember that next time you drive past a field with combine harvester spewing out husk dust, your engine will be breathing in some pretty harsh abrasives!

Filtration quality is paramount, if you want your engine and turbo to last!

 

Sorry to jump in on this thread but breathing for the car is an avenue I'm currently exploring with my Hawkeye STI.
Being new to the Impreza scene I have no clue on what method gives best results:
Leave it standard
Swap out the panel filter for an aftermarket one (in which case which one)
Swap out the panel filter for an aftermarket one (in which case which one) and drill the air box (very common with the VR6 boys - where I've come from)
or bin the lot and get an induction kit!

Which of the above options would you guys suggest would sees the best gains for a 56 plate Hawkeye STI?

 

Ian's cars prove pretty relaible.
And having used K&N filter on all but one of the 6 Scoob's of various types I have had so far, the other was a Zero Sport CAIK on a 330BHP Foggy STi, I have never had a dead MAF or problem with them.

I don't think that most of the Scoob's on here will "green lane" but most farmers with Leggies and Foggies (the original market years ago and still strong) use the OE filter, I also have and it was excellent, but they seem to go on forever.

"Which filter" is a whole can of worms and there is no definative answer. Performance or filtration, extremely difficult to measure,

 

It is indeed a can of worms, so I guess a good way to prove filtration efficiency over a period of time, on a car, would be to swab the feed pipe into the turbo, and test for particulates.

I think people tend to think of the environment they live in, to be the same as for others, but of course this is not the case. Those living in an urban environment will generally have much less exposure to airborne particulates (dust), than those living in more rural areas. The more dusty your environment, the more work your filter has to do, and the faster your filter will blind.

Even the slightest dust contamination will damage the blades of your turbo's compressor, and over time it will become less efficient.

I think on the whole this 'oil migrating onto the MAF' thing is a bit of a nonsense, so long as the air filter element is kept cool. In very hot climates, or if the filter is directly exposed to under bonnet temps (cut air box or cone filter for example), then the oil on the filter will naturally become less viscous, and could their fore become more susceptible to being drawn out of the filter. The risk is also increased if the filter is over oiled after a service. I've lifted performance filters out of their sealed air boxes and found oil residue within the dirty part of the box, as well as in the clean side too.

In the absence of scientific evidence, this is a topic that could well go on forever. People have thier own brand loyalty, and will sing it from the hill tops to show their praise, no matter how misguided it could even be.

Filtration quality matters, so just think about it before choosing the right filter for you. Subaru did, and that's why I use a genuine STi filter.

 

Thanks very much everyone for all your input.

As you said Natural Born Chiller, it is a can of worms that can be debated 'til the cows come home!

OliVeR6 - Either of the 1st 2 .. I would not drill holes in the airbox! I have been on the scooby scene for about 10 years and have never heard of that . Recon that'd cause a lot of problems ,pretty much you'd have the same problems as when fitting the cone-type filters ( if you dont have a cold-air feed ) as there's a lot of heat in the engine-bay and that would get pulled in and would not help at all.

Despite everyone's opionions here I went for a Pipercross one , mainly 'cos I remembered I had 1 of these a few years ago in my 2005 WRX PPP and it added a bit of induction noise and had no problems when it was fitted .. plus my local Subaru dealer who I bought the car from ( and should have shares in since I've bought 9 Imprezas from him over the years ) sells the Pro-R stuff for all their Imprezas , and the Pro-R filter is made by Pipercross .. if it's good enough for their new STis it's good enough for my 2.5 WRX PPP

Cheers,

Steve