NEILB1

iTrader: (9)

What would you do or have done ? I AM TORN between both options, I hear that the cone filters can damahe the maf sensore etc but you also get a good sound from them

The pannel you get no sound at all but still have just as good airflow to the engine and have alot less chance of damaging the maf

Or am i best just to leave the standard panel inplace ?

R5_GTT_Steve

iTrader: (7)

I voted panel but only because i have a MAF , if i was to run MAFless and a front mount then i would have no choise to go cone.

IJE71

Definitely replace the standard filter. I have a bugeye with a K&N panel filter which is all you need unless you go over 350 ish BHP.

NEILB1

iTrader: (9)

that has answered my question

unfeasablylargegonads

iTrader: (3)

+1

john5f

iTrader: (3)

+2 mine's Green

Evo Bizz

iTrader: (1)

+3 Pipercross for me.

Rich D

iTrader: (12)

I run a Pipercross panel filter in mine, better flow than a standard paper filter, but probably doesn't gain you a lot

no way I'd run a cone filter in an Impreza in summer, have you felt how hot it gets under the bonnet?

MrNoisy

iTrader: (28)

+3 for Green. TBH they're all much of a muchness cotton panel filters from the figures the manufacturers post.
It's not like you're going to gain 10bhp with one, and 2 from another .
Go with whatever makes you happy.

If you want one that doesn't suck in air from the engine bay, either get a wing mounted kit or something like the K&N Apollo which replaces the airbox, but still has the filter inside a protective housing. Still doubt you'll see massive increases in performance though, unless you're in the 300+ bhp crowd.

And as another spelling police member already pointed out it's "Panel" not pannel or PANNLE - sorry couldn't resist - OCD kicking in

NEILB1

iTrader: (9)

i am not looking for extra power, just seeing what is the best option for the engine as i have not done any mod's at all yet, Apart from the prodrive back box,

Just looking to get it to breath easy first of all,

StevoT2000

Green panel filter for me also

peter zippy reid

iTrader: (25)

green panel filter for me

cookie79

i use a hks super panel filter

ginger321

Me too.

Had an induction kit on my silver wagon during last summer for about a fortnight - june - car felt as if id lost power - standard airbox back on and normal service resumed

f4la k

iTrader: (1)

Apexi induction kit for me but im mafless and fmic. will be getting it cased in soon with some heatwrap around the casing and a cold air feed.

Anders_WR1

iTrader: (8)

Someone ran a test on standard vs aftermarket and there was little difference in power (2-3bhp). But the aftermarket panel filters will let crap in to the engine, so stick with OE unless your going for 400+

Anders

MrNoisy

iTrader: (28)

I'd say the statement re aftermarket letting more cap in I'd have to flag as questionable.
Cotton vs paper...hmmm...

Jimbob

iTrader: (13)

From my understanding the cotton gauze like K&N has larger pores (holes) in it and can let dirt through, also the oil they are coated in can knacker Mafs, so I`d say a non treated foam panel filter is the way to go, as the larger the surface area of the filter the better it will work and under less stress. Will be getting a foam filter for mine unless I go MAF less with a FMIC (which is a distinct possibility tbh).

But paper (when new) is better than a K&N for pure filtration, but K&N flows more air due to larger holes. If you stay paper filter just change it regularly.

Jimbob

iTrader: (13)

http://www.bobistheoilguy.com/airfilter/airtest1.htm

Something to read, dunno how un-biased things are. As most comparison things are made by companies who sell filters so take with pinch of salt.

corradoboy

If you want noise, remove the intake resonator and ram-air scoop. There's little to no extra power available from any filter, with ±1.7bhp spread found by Harvey Smith when testing O/E, K+N, STi and HKS Green Sponge filters back-to-back, and repeated over two consecutive days. The STi filter gave least power but had the best filtration, OE gave highest power, and foam filters proved the least effective at filtration. His findings were verified by Mike Smith of Prodrive as similar to their results, hence why no PPP option has ever featured a filter, and Scoobymag also had similar results. The only real justification for getting one is if you intend to keep the car long enough to make a lifetime filter economically viable, or you just want one.

All IIRC

greatgonzo

iTrader: (1)

K & n for me
Comes with a cool sticker that goes on the air box to remind the mechanic not to through away at service time

slyv12

iTrader: (3)

just got a Ramair enclosed cone filter to replace the Pipercross cone that was suffering from heat soak and causing a missfire at 2000 revs.
Lost the induction noise but also the annoying miss too. Got a new maf so no problems at all now.

pockscooby10

well i'v had a hks induction kit on for around a year and i'v had no problems with it so far. but then again i'v also got a green panel filter in the original air box for when i get bored of the noise from the inducton kit.
to be honest i think it's down to personel taste.

chris-RB5

Totally agree with you!

Neil B1 if you want your car to breath just remove the resonator box and change the oe filter at regular intervals!

Splitpin

This is an urban myth. The only way the oil on K&N/Green-type filters can "knacker Mafs" is if the filter is cleaned and far too much fresh oil put on afterwards. On a new filter, or if K&N's cleaning instructions are followed to the letter there is no such risk. Would imagine the same applies to Green seeing as the construction is all but identical.

Similarly the comment re the nature of the cotton gauze having "larger pores" allowing dirt through fails to take into account that the structure is three dimensional.

If anyone is concerned about dirt going through their filter, it's easy enough to test - just remove your MAF sensor element and wipe across the front of it with a piece of white tissue. If the tissue comes off clean...

As has already been said though, there is little, if any, room for a power gain in this area.

Removing the resonator doesn't significantly improve "breathing", at least on a post-96MY car, although it will increase audible induction noise. However it also has a slight downside in terms of marginally reduced airflow measurement accuracy/consistency on a MAF car, which is unlikely to be an issue on a standard ECU, possibly moreso on a custom map in which the margin for error has been tuned out.

harvey

iTrader: (48)

Thanks for quoting that Corradoboy.

My findings on removing the resonator box was that the car dropped 7 bhp.
This was simply removing the resonator box and running the car on the rollers again. I repeated this on another day and got exactly the same result.
My conclusion was that air flow was disturbed and turbulent past the MAF and resulted in reduced performance.
There were two things that may have altered the result more favourably but as I was ditching the ECU in favour of a MAFless Simtek I did not carry the experiment any further.
Puting a bridge or trumpet on the end of the air inlet tract might have smoothed out flow over the MAF sensor and led to some improvement.
Secondly some of these cars are incredibly sensitive to fueling when alterations are made to the inlet tract. I conjunction with a trumpet to smooth the air flow, had the car been remapped there would probably have been an improvement in power.

Splitpin

As above, concur with that. The tests I did with the resonator out revealed a significant amount of pulsing/turbulent flow, with the MAF sensor output peaking and troughing worryingly as a result - with corresponding inconsistency of AFR. My tests were run with a cold air inlet in the wing with a swept 90 degree bend and a nice smooth trumpet on the end of it btw.

The conclusions I drew from this is that the resonator chambers, aside from reducing induction noise, play a significant part in smoothing out turbulence and pressure fluctuations in the inlet air, allowing the airflow meter to work more consistently.

As you say you didn't carry the experiment through, but in mine, the spiking in the MAF voltage was so marked that, had I mapped it in that condition, rather than develop more power in the end, I would have needed to add some extra fuel to make sure it wouldn't lean off too much during the troughs in the MAF readings. Running with the resonator allows a leaner mixture than would be safe without it.

harvey

iTrader: (48)

This is all tending to suggest that the resonator delete adding more power is another one of these Scooby myths.

NEILB1

iTrader: (9)

well i will be leaving it all as it is going of what you fellas have just said

TonyBurns

iTrader: (3)

I had some very good gains with one of these on my old spec c will try it out with the new one (though this one is mapped for uk fuel, my last one was on a standard map and the STI panel filter is specifically for the JDM market car).

Ive ammended that last bit they use to use ramair filters on the pre MY99 car PPP's

Tony