I had a dirt track car many years ago and with KN we would always find oily dirt in the carburetor mouth. Their claim to why they even filter with such big pores is that the gauze fibers vibrate with airflow and filter better than with static flow.

But I digress. Dyno tested a drop in kn filter in an frs and there was zero difference anywhere. Hell. We are averaging 1 to 2 hp with entire cold air kits which is hard to see with normal run to run variance.

http://www.ft86club.com/forums/showthread.php?t=13245

^ +5whp gains for drop-in filters. ^

I don't know what to believe anymore. I've been seeing and hearing the same pro/con arguments for 20+ years now and still no concensus. You won't sell many drop-in filters if they don't add something so the motivation to produce positive results is certainly there. It wouldn't be hard to provide slightly more favorable test conditions, even unintentionally.

Still, in theory there should be some slight improvement in VE by reducing the airflow resistance of the filter and it is well known that oiled cotton gauze has lower resistance than oem paper. OTOH OCG also allows more dirt to pass so there really is no free lunch here. In the end I went with K&N hoping that they know the correct balance between increased airflow and filtration efficiency.

They did something wrong if they saw any power gain with a drop in. I don't sell product. I just dyno tune and test. Tested it. Zero. Back to back.

If anyone wants to send me something to test.... id be happy to.

If you wanna see if your filter is the restriction its pretty easy without a dyno. Go on ebay and buy a magnehelic pressure gauge or differential pressure gauge. Something in the 8 to 15 inch of water range and map your induction system.

Just ordered a green, will post a quickie on how I like it. :)

Not everyone lives in the desert

Just replaced my filter with a K&N, from previous history with Harleys, it's an easy couple horsepower increase for 5 minutes of work.

Looking at the original FR-S filter it's hard to believe it could breath at all. Looked more like a dust filter for the inside of the car.

I've had an AEM Dryflow in my car for almost a year. They make them.

Just another warning: had an over-oiled K&N and it was spitting back -- had to have it cleaned out and wiped off. Make sure you wipe yours a little before you drop it in otherwise you'll get a nice pretty CEL ;)

might be worth cleaning your MAF sensor if that happened to you. Just remove the MAF sensor and spray it down with some CRC MAF cleaner.

Yep, that was part of the cleaning process. Headache, shoulda just wiped it from the beginning! :bonk:

Drop in??? I know they make universal filters.

Sorry, I meant aFe Pro Dry filter. AEM, aFE, I got confused. Anyway, this is the one I went with:
http://www.autoanything.com/air-filt...A4151A0A0.aspx

I just installed the k&n drop in air filter during my lunch break, and the first thing i notice it that definitely there is louder. I can hear the air intake when when reving 4-5k + rpm.. I still need to drive it more to see if there is any noticeable throttle response

After driving the car car for a while with the new k&n drop in filter, i can say that it does improve throttle response a little bit. Its more noticeable around 5k +

Worth the 50$ IMO..