Hi all. I was wondering if anyone had bought an aftermarket panel filter and wanted to know if anyone had an opinion as to which is the best.

I dont want an oiled filter as i have heard that they can mess with your air flow sensor.

If anyone has any of the following i would be thankful for your opinion and any feedback.

Green Cotton Panel Filter
KnN Panel Filter
STi Panel Filter

Thanks, Rave Dave

 

Ive an STi Panel filter fitted to my MY03 JDM STi, had the car on the rolling road before/after, and saw a 12bhp and 15lbft increase with the STi filter fitted though it does depend on what car your fitting it to though as JDM STi's are pretty restricted with the normal filter.

Tony

 

The fears over oiled filters mostly came about with the ITG one and the 98-00 cars. The ITG was excessively oily and contributed to many MAF problems, especially in cars of the aforementioned years due to their sensitive hotwire MAF's. Green, K&N and JR Racing are all good products and have no history of problems to my knowledge. The STi filter which Tony mentions is well respected too, but it must be pointed out that it is a serviceable item and thus must be replaced at each service whereas the others are lifetime items which can be cleaned and refitted. It also came bottom in a test done by Scoobymag for flow rates, beaten even by the OE paper item.

 

This is true but it was tested on a WRX and not an STi for which it was designed for hence my good (even better than any of the above scooby mag tests) results

Tony

 

Well i have an MY02 STi Type UK so the results should be similar.

Those are quite high figures and much higher than i was expecting.

Does anyone have a link to this review?

So which one is best???

 

The K+N is an oiled filter but in my experience gives no problems. Problems could occur if the filter is over oiled.
Recently I spent two half days on accurate rollers carrying out various tests.
Some of my findings were as follows:

Removing the snorkle/inner wing resonator reduced power by around 10 bhp. Air flow was disrupted and AFRs were effected.
Replacing the snorkle and power returned to the previous figure.

There was just over 2 bhp difference between the best and worst pannel filters. Each filter was tried twice but the results were consistent.
The HKS sponge type with no oil produced most power, however the filtration may not be as good as the others.
Surprise, surprise, next was a new Subaru O/E. Filtration appeared to be good.
Next the K+N which I assume has good filtration and next surprisingly was the STi pannel that many people rave about. Filtration on that is obviously good.

I am told, although I have not seen the article that Scooby Mag did some tests and concluded that the STi pannel reduced their power. Can anybody reproduce the article???

These tests were done on a Dyno Dynamics RR at TEG Sport.

Because the differences were so small, I am a fan of the K=N as it can be cleaned and rewashed and I would expect that filtration is also good.

 

Harvey,
Was the airbox left with a gap to the wing or did anything get added to replace the resonator?

Were these all new filters?
Any results with filters with 5/10k miles on them?

Nick

 

There was no gap to the inner wing as I foolishly had cut off about 35mm from the resonator box so it butted up exactly. I had to use another resonator box when I refitted it.

The STi and O/E Subaru were brand new, out the box. The k+N was washed and oiled per K+N instructions the day before and the HKS was washed in warm soappy water per the cleaning instructions, also the day before.
The K+N and HKS would both have done around 40 miles each while I did some AFR checks and took the car over to Cumbria.

 

Cheers Harvey,
I also assumed that the resonator allowed a large pressure drop, so I changed it for 300mm of 3" drain pipe- guess I'll have to reconsider it.

Nick

 

So whats the final verdict??

K&N, Green, JR Racing or HKS????

 

Whichever you like I think Little to be gained from any so go for the cheapest.

 

simota

 

How about the TSL Filter?

 

I think i will get one of these...£30 you cant go wrong..

http://forums.sidc.co.uk/forums/707033/ShowPost.aspx

 

Harvey

Your test seems to have got the same results as our's. There's just about nothing to be gained in flow compared to a new std filter but possibly everything to be lost due to particles getting through.

Mike

 

Mike: I am honoured with your reply and chuffed that such a well respected company and I have come to similar conclusions.

Nice to see Prodrive are doing it right!!!

I did these tests carefully and with an open mind and had to repeat them to satisfy myself that my fist set of results were valid. My concern with the HKS green sponge pannel is that it is passing particles of a bigger microns than the others which in time cannot be good, especially in a dusty/dirty environment.

Claims of big gains from a pannel filter change only are rubbish as far as I am concerned.

Good luck with your current projects and I hope your venture into F1 is worthwhile. New blood might shake it up a bit.