pslewis

I hear a lot about K&N Panel Filters and how they can un-leash massive amounts of power ..... you know me - I'm not stupid when presented with claims like this

Now, these Panel Filters are silly money .... £45 ..... ..... so, maybe they work - but how?

They look just like the standard BluePrint Panel Filter - but the BluePrint version costs £4!!!

Thinking through what could possibly give a rise in power, I can only come up with the thought that the K&N doesn't filter as well as the standard versions ...... so, cheaper to make and should be cheaper to buy?

I take it these are not coated in MAF killing oil?

So, why do you buy something which gives less performance (in filtration) than standard items costing a 1/10th of the price?

Myles

iTrader: (40)

I dont know who this is aimed at but it seems to be common practise to buy the OE STI panel filter, or at a push, a non oil soaked filter. I use a Simota filter personally, my car is still alive, just. Without a knocklink may I add.

pslewis

Not aimed at anyone ..... just a question to open a debate ..... I would agree to fitting a Subaru STi Panel Filter (is it different to a standard Impreza?)

Myles

iTrader: (40)

Im not sure about the difference between the standard and STI filters. I think anyone that uses an oil lubed filter after all the warnings on here and other sites need to check their heads.

I had my MAF cleaned today after a resonator delete, and it was dirty enough to give me slightly rough running and hesitation, I wouldnt like to guess what an oily filter would do to the MAF.

99greenwagon

iTrader: (39)

i personally think its all a bit of a hyped up load of s**t,u are certainly not going to get much gain from any variant of panel filters,i use genuine subaru oe filters and i think they are as good as anything,not worth messin about with. if any one disagrees with me.....then please note this is just my opinion. im not saying that u cant /can get better filters etc. the oe ones filter well and are fine for me.

pslewis

Well, yes, oiled filters are very bad news ..... and anyone fitting them need their bumps feeling.

But are K&N Filters just very bad at filtration - to allow more air through?

I'm not convinced that the STi filter is any different to the standard ... why would Subaru risk one engine and not another?

99greenwagon

iTrader: (39)

just buy genuine subaru oe filters and u wont go to far wrong.

360ste

iTrader: (1)

The main selling point of the K&N filter and the other similar filters is that you clean them then re-oil them rather than bin them. If the filter is cacked in oil then it will knacker the MAF sensor but if oiled correctly there should be no problem. A lot of the problems have come from fitting the induction kits due to the turbulant airflow. I recently relocated my MAF sensor so that it is a blow through not a suck through, using the turbo and FMIC to smooth out the airflow.

pslewis

I see, so it's a cost thing .... that the K&N can be reused?

At 10 services it starts to make financial sense then ..... I wouldn't want the same filter on after that length of time (re-usable or not!).

So, they are basically pointless ..... like a lot of things sold as 'upgrades'!

paulwrxboro

Pete hold a sheet of paper up to your mouth and try and breath threw it, now hold a woolen jumper up to your mouth and breath threw it.....thats the difrence
and a K&n lasts a life time

pslewis

Yes, the woolen jumper has allowed more contaminents into my lungs .... the paper stopped almost all impurities.

So, you are saying that the standard is much better for your engines lungs? But the less good at filtration (the K&N) lasts longer? Well, I guess it would last longer - it is catching much less crud .........

I may stick with the better standard item then ..... so often I find standard is best - seems it is again?

greatgonzo

iTrader: (1)

There is a thread some where showing all the main manufacturers and what one has the best filtration and best flow
There is a difference and I think a well worth mod

99greenwagon

iTrader: (39)

correct.

johnlogie

iTrader: (4)

Different materials will not filter(or flow air) in the same manner. K&N , cosworth etc will have researched and tried many different materials to achieve a greater air flow with out comprimising on filtration. original subaru filters "do the job" and have to be cost effective to subaru(if they can save for example £30 a car then thats a large saving). This does not mean that there isnt a better alternative. IMO

paulwrxboro

Pete if you can suck that good, your in the wrong job

pslewis

I'm no sucker .... I don't spend £45 on less filtration ....

pslewis

We are close to the 550 BHP and 30 mpg arena now ..... the bending of the laws of physics once again

More airflow = less filtration - it cannot be otherwise.

I'll stick with the OE filtration I think ...... £45 is a lot for less.

Splitpin

Who's been saying they unleash "massive" amounts of power? On their own, they don't. A handful of extra horsepower if you're lucky, especially if compared with an aged paper filter.

A standard Subaru panel filter costs something like £18 now, and should be replaced every service. The K&N/Green type oiled cotton filters, as has already been said, are "lifetime fit" items provided they're cleaned every few years. IIRC the K&N recommended cleaning interval is 50,000 miles.

As you say pattern filters are cheaper, so you can take your pick over which offers the best approach.

Theoretically via the use of a more efficient filtering method.

No they don't, and if you'd put the two side by side you'd see the difference straight away. The OE spec filter is almost literally made out of toilet paper, only thicker and impregnated with a preservative that stops it disintegrating when it gets damp. The K&N and Green types are a fine weave cotton impregnated with a small quantity of oil.

No. IME they catch the same amount of crap while not restricting the air quite as much as a paper one.

Correct. The K&N/Green type are coated with a very small quantity of oil that doesn't shed - unless unsuspecting owner ignores the cleaning instructions, and refreshes his element on the "more is better" basis.

The error's in the generalisation. There's a fundamental difference between the oiled cotton type and the synthetic foam sort covered in a high viscosity "mucus" that used to be popular a few years ago. The cotton fibres absorb the oil and retain it, so it doesn't get pulled off in any significant quantity.

The synthetic foam doesn't absorb the gunk in the same way, and so on those, over the course of time the medium literally gets sucked off and into the engine. This not only reduces the efficiency of the filter, globs of thick sticky stuff hits the MAF element.

As for "checking their heads", as you'll know from my extensive posting history, caution's one of my middle names. And it's because of that I've got no issues with running an oiled cotton filter.

corradoboy

I've quoted this loads, but Harvey found a ±2bhp spread across a range of filters from OE paper, STi, cotton mesh and foam filters from various manufacturers. The OE paper item was amongst the best at filtration, with foam and the expensive (considering it isn't lifetime) STi being worst. Given the minimal power differences they are not worth it, unless to save money over 10+ services with a 'lifetime' item such as K&N or Green. Similar conclusions were found by Scoobymag too.

johnlogie

iTrader: (4)

So my k&n cone isnt filtering correctly and should be replaced with a paper cone?

Cannon Fodder

iTrader: (100)

I have used various forms of K&N induction products for a long time on a lot of cars and I have never had any problems at all.

Have a look at the link below for some answers to your questions Pete :

K&N Frequently Asked Questions (FAQ)

And as for the urban legend regarding MAF failures :

K&N Response to Mass Air Flow Sensor Concerns

I would ask as well if K&N air filters/induction cones are so rubbish why do Roger Clark Motorsport use them in their induction kits (and yes I have one).

TonyBurns

iTrader: (3)

CB, the STI one gave the best filtration with the exception to the standard subaru one but all were tested on a wrx and not an sti so no real conclusion to how well they filter across the range of cars, and unlike the rest, the STI filter is a maintenance item and needs replacing every 20k miles, but I saw huge improvements when fitting to my old spec c on the rolling road, never looked back after that

Pete, the STI filter is a JDM market only filter (subaru uk dont do them, you have to go through a 3rd party to buy one but it is an official STI item)

Tony

Terminator X

iTrader: (7)

Dare I suggest he try it with a plastic bag over his head

TX.

pslewis

Now you have wasted your money you may as well keep what you have - hopefully it won't kill your MAF.

But paper OE is clearly best in all relevant tests - which is what I thought actually

Cannon Fodder

iTrader: (100)

Properly maintained oiled cotton air filters/cones do not kill MAF sensors, again this is just an urban legend that has been allowed to snowball.

Not that the facts ever got in your way Pete...

Also Pete, what did you think of Splitpin's post, as you do not seem to have commented on it.

johnlogie

iTrader: (4)

It will have a very hard job killin my MAF as its in the bin. Im running a SimTek

bob r

iTrader: (46)

Well you and I know he won't comment on a post like that as Splitpin is very clued up Pete won't be able to make him look a fool like he tries to with most others on here.

Pete knew the answers to his question before posting but 'creating' is what he does, and does well.

MICAWRX

I had a K&N Panel Filter fitted on Saturday.... It hasn't broken down yet and is running like the car has a PPP installed.

The only thing I can think that can have made the difference is the K&N Oil mixed with the Total 97 Ron Fuel has given a better stoichiometric mix....

.....Sorry can't keep it up, but it would have been interesting to see how far it got round the forums... I wish I hadn't bought it now after reading this lot!

GREGGYG

iTrader: (2)

pslewis, you're back?????

Where have you been all these years? Or is it me who's disappeared?

Scooby Wagon Addict!

iTrader: (10)

Hi .. I'm now curious to peoples' opinions on here after reading this.
When I bought my 05 WRX I put a Jetex/JR Racing filter in instead of the OEM Paper one .. I've used these before in previous WRXs , just this time there isn't really that spooling-up noise I got with previous PPP'd ones ( I discovered it was the removing of the Cat in the PPP that helped make this noise). So I'm thinking of either refitting the standard OEM filter or buying an STi one from Scoobyparts or like. It's only got the Prodrive backbox fitted and not remapping it or anything for more power.
What would you do?
Cheers,
Steve