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Discussion Starter · #1 ·
Was in the dealer today to get a new air filter element, then the confusion set in.......dealer brings out an sti type drop in filter that is the same size as the stock one but NOT the same material.....had an sti emblem, mesh screen.....reminded me of a K&N type that I had on my old wrx.......it does not appear to be the normal paper type filter that came with the car.
Anyone running one of these? I know it's not going to improve performance much but the cost is substantially HIGHER than the typical paper element. Yet the other element they had in stock did not appear to be the same as the one I pulled from the engine either so I'm not sure which to go with.
 

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filter

do not buy the drop in sti filter or the OEM stock filter the sti is a different material and flows slightly more than stock, but sti filter is a throw away you can not keep using it like the K & N which as we all know is reusable.... the K & N is less money than STI filter and works as well or better......
 

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Appears they are attempting to add the STi drop in filter like I bought for mine. I enjoy it, power increase seems to be mild. Intake sounds increased a bit. I would recommend it.
 

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I have the green element and works fine without the box that is in the fender and you can listen the turbo thit I explain correctly my english is not that good :rolleyes:
 

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I had the same experience at my dealer, but did you notice that the STi $90 filter and the $20 standard STi filter both are oil elements.

My service person said the $20 stock filter actually works better in the STi's he's ran tests on -- but again that is what the Subaru service person said -- take it for what its worth.

Rob.
 

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The stock paper and STi air filter should both be oil-free. The reason that some advise against using a K&N or other oiled air filter, is that the oil can flow through the filter and contaminate the MAFS (sending the ECU different readings). When I used an ITG drop-in air filter in my WRX, after a couple of months there was a puddle of oil at the bottom of the airbox. I have since used the Blitz LM paper air filter drop-in.

So, it is best that when you clean/re-oil your K&N-type filter, you are cautious in not over-oiling it.

-Mike-
 

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Mike,

I can assure you that both Subaru $20 STi replacement filter AND Subaru STi $90 filter are BOTH pre-oiled from the factory. They come in a sealed plastic wrap in a box -- the reason for the plastic wrap is that it is an OILED filter. I can provide you with pictures if you like.

However, oil pooling that you experience would indicate more of an issue with your valve case breather re-circulation/PVC -- pooling is rare for even K&N filters that are over oiled -- I mean someone would have to really soak the filter but over time even that oil would eventually sees its way into the combustion chamber and certainly not enough to generate pooling.

I've used K&N filters on my race car and never experience oil on the MAF sensor. But keep in mind that K&N filters do NOT filter out as much dirt and hence their higher flow rate -- not a big deal for race motors as they rarely live long enough for dirt to be an issue ;). However, the combination of more DIRT and oil could cause problems for longer term street driven motors.

Rob.
 

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No, it was not blow-by. The oil on the ITG filter has a gummy/sticky texture, and that is what collected at the bottom of my airbox. It was not motor oil consistency. However, I must add that although the oil pooled in the air box, there was never any on the MAFS. Here is a thread on the matter;

http://www.clubwrx.net/forums/showthread.php?s=&threadid=13929

I'm still surprised that the OEM paper air filter and the STi filter are oiled. When I removed my stock one after ~500 miles, it was just a dry paper filter. I have never purchased a replacement, however.

I've used K&N filters in other cars before, and never had a problem. But, I never over-oiled it either. ;)

-Mike-
 

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Im sure there is nothing wrong with the oem... you have a turbo thats going to pressurize air before it's cooled... Im sure the paper is not a factor in performance... the regular wrx intake and filter is good till 350hp...

Also... K&N's exhibit dropoff in CFM once theyve been used, and they decrease with every 10kmile clean. If saving money is what your lookin for, get a K&N... Just keep your maf clean and youll be ok.

Or if you want consistent good performance, buy a bunch of stock filters from subaru parts.com They are garuanteed to keep your engine clean, and your maf happy
 

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FYI, I inquired to SoA about the air filters. Here's the response I received;

Thank you for visiting the Subaru Web site and for your inquiry. We appreciate you taking the time to contact us.

I've spoken with our Technical Services Staff and was advised that none of the air filters in Subaru vehicles are pre-oiled (or oiled), as this may cause damage to the vehicle.

I hope this information is helpful to you, but should you have further questions, please let me know and I'll do my best to assist you further.

Best Wishes,

Natalie Cox
Subaru of America, Inc.
Customer Dealer Services
-Mike-
 

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oil or no oil?

I just pulled my air filter this weekend from my '05 STi to put in the K&N from my '02 WRX Wagon. It definitely had something on it. I don't plan to do a chemical analysis but it sure seems like oil.

My '02 paper element also had oil on it.

SoA is wrong and it isn't the first time.
 

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I remember the days I used to contact SVT when I had my 99 Mustang Cobra -- it was 50/50 on whether they were accurate or not.

SOA, is probably the same way.

The filters are oiled. But has anyone removed their intercooler, you'll see oil in it also. The bottom line is -- oil is actually good for the valves and combustion chamber, burning a little oil will make the motor last much longer. The motors are designed to receive some amount of oil in the combustion chamber -- this is NOT a bad thing.

When I see some folks with the Perin bypass, etc. etc. it makes me kringe.
 
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