Uncle Fester

I've read a few posts recently that making me have second thoughts on getting a high flow filter for the S2000. It's my understanding that in order to obtain more flow, you have to filter less. Do the filters that use oil as part of the filtration method filter less? Does anyone know if there is a difference with the filtration ability of cotton vs. foam? Does one filter better than the other? Do they flow the same (approx)? If the high flow filters to filter less "dirt," is the dirt that gets in something to worry about anyways?

These are just some of the questions I'm tossing around in my head. Can someone enlighten me on this?

p.s. I understand that the high flow filter doesn't gain much power (if any) over the stock filter. The thing about high flow units that attracts me is the reusability factor. I'm generating less waste by reusing the filter, so in the end, we all win.

Thoe99

I think I can recall reading about K&N filters being pretty much the only ones that add HP to the S2000, unless you go the cold air intake route. Most other air intakes take away power, if not anything.

I have a K&N air filter in my car, and it really improves the airflow during high rpm's. Yes, higher airflow equals less protection, but I'd only watch out if you're driving in dusty areas.

xviper

The stock S2000 filter is quite good to begin with. It's main downfall is that it must be replaced when it gets dirty and it's quite expensive. Any drop-in aftermarket "cleanable" filter won't show measureable gains. 1-3 HP is not something to get excited about as this is within the normal error of a dyno. Your "butt" dyno may tell you something, however, butt dynos aren't exactly scientific.
As popular as K&N filters are (I've had them in most of my previous cars), it has been reported here that the JR filter is a slightly better drop-in one in terms of filtering ability and flow. I've had the JR for a while and the only reason is for re-usability.
There was a post here that linked to another report done by a trucking company who experimented with the K&N filters for a significant period of time. They discovered that using the K&N resulted in much dirtier oil (through analysis) than on those vehicles which continued to use the stock filters.
K&N sells a gazillion of their filters every year, so who's to say?

Destiny2002

I believe your fears are justified.

Here's my opinion (didn't want to type it all over):

https://www.s2ki.com/forums/showthread.php?...790#post1062790

Surf2k

This is the reason I haven't opted for a PRM or other CAI. You gain some power at the expense of engine life.

txst

I'm also one of the believers that the "high flow" fliters generally don't filter as well. I would rather have the protection of the stock filter.

I have always wanted to run some tests in our lab on filters and their ability to flow air. We have the capability to measure flow rates and pressure drop. I just don't have any desire to go out and buy a bunch of filters....

Ron Jeremy

I don't worry about it. The K&N flows more because it's obviously more airaided. The stock filter isn't as airaided. I would say that both filter out contaminates the same because the stock filter is more dense paper or cotton, but the K&N has oil in it that attracts contaminates and sticks to the filter. I don't know how to explain this.
K&N - better air flow with oil that attracts the same amount of contaminates that the stock filter catches because it's more dense but in return causes less air flow. Is that as clear as mudd?

MacGyver

Not quite, Ron. Hold you fingers up as if you're telling someone 'OK'...imagine this is the size of the holes on a K&N filter. Put some oil on it, and it sticks to the sides of the hole. Now, make the 'OK' circle smaller, as if your whole hand was grabbing a pencil....that would be the hole size for a paper filter, like stock. The only way one can flow better than the other is to have a larger open surface area. The K&N accoplishes this with larger holes, but oil surrounding each one in the hopes that if a particle gets bumped through and around enough holes, it will stick to the oil. With an oiled filter, you have a greater chance of catching smaller particles (the oil snags them), but generally a smaller chance of getting the same percentage of total particulate matter. Hense, the K&N will flow better, but the stock will trap a higher percentage of particles.

VTECPHIL#6829

I am a firm believer that K&N Filters let a ton of dirt through. Unfortunately, the Vortech we will be installing comes with the K&N, so I am planning on putting an "Outerwear" over it. These can be purchased at motorcycle shops and are a foam "condom" so to speak, that goes over the K&N to add extra filtering. I am hoping that this helps, as I live in a very dusty area. I wonder what other filters can be adapted to the Vortec set-up?

FormerH22a4

more flow = less resistance = more holes = more dirt getting pass.

This is why I am not going to use K&N.