What air filter set up is every one using.

[Dessertrunner]

As part of fixing my air intake problem I have been driving (short term) with out the air box in the gaurd. What has surprised me is that the car revs out better etc with out it. The car has more power. This has lead me to think what power can be gained by developing a better air filter system.
So whats every one using.
Tony

[Dessertrunner]

Stuffed up and posted twice but here is a articale that deals with our Air intakes but on a WRX.
http://www.autospeed.com/cms/A_1605/article.html

[redlightningsvx]

i'm running a cai with a green cylinder filter from dayles

[Crazy_pilot]

Stock thingamabobber with a K&N filter. Although I've heard the oil in those filter can foul your MAF in the long run, and they don't clean the air as well as paper filters. I didn't notice any appreciable difference in performance.

[black beast]

Dayles Cold air piping and a HKS race foam filter, i think it feels faster...

[Nevin]

Running a fender-well intake of my own making with 3" aluminum piping and a cheapo Autozone filter. (not the one with the screen on the end...ewww)

Seems to work well. Not as pretty of a sound as just a filter mounted on the MAF, but it seems to keep its power better throughout the day. I imagine it has something to do with taking air from outside the engine bay.

[YourConfused]

I have a Kool air filter (K&N) in the stock box. Resonator delete, and modified air box tube. Insulated snorkel w/ some 3M silicon foam and bonded aluminum stuff.
I know the filter isn't worth much, but I had the oil and cleaner sitting there doing nothing so I just bought another filter to use the stuff on.
My exhaust muffles any intake noise I may have gained with the mods.

[Dessertrunner]

I have purchased a gauge as mentioned in one of the Auto Speed articles to measure the negative pressure at the different positions on the intake. This should tell us exactly what we are dealing with with soem solid numbers. It would be good to do a dyno as well but not sure about that.
Tony

[Dessertrunner]

The new gauge has arrived to measure the negitive boast on the SVX intake system. I plan to measure the following :-
Loss in airbox (inside guard)
Loss across airfilter also for different types of filters.
Loss from MAF to throttle body.
and depending on what I find, the loss in the MAF unit.

I will let you know what I find when its done.
Tony

[Dessertrunner]

Here is what it looks like.

[Trevor]

A very worthwhile project Tony.

The instrument you have purchased appears less sensitive than I would have expected to be required for accuracy. Don’t forget to adjust the zero.

It will certainly be interesting to see the results with readings across each likely point of restriction. How are you going to measure loss in the air box?

Good one, Trevor.

[TomsSVX]

I have been suggesting in fender cone filters for a reason.

- The stock airbox is a "cold air" already. it feeds ambient air from the fender already so a CAI is not going to improve air temperatures.

+ the reason i suggest an in fender cone filter is that it will draw the same ambient air as the stock air box... BUT... it smooths out the intake track. The stock airbox is like merging a 6 lane highway down to 2... Its gonna slow velocity down. It creates "dead spots" in the intake which during high rev's and high flow will become an obtrusion. The in fender with a cone filter creates a smoother track for the air to flow in and decreases turbulence.

Thats the reasoning behind them for me.

Tom

[LetItSnow]

I picked up a K&N panel filter from a guy with an STi who opted for a short ram setup.

The key? Don't over-oil 'em! Another guy I know who has a WRX put a little too much of the red stuff on, and it coated the MAF nicely, which was most evident to him in that his fuel economy was absolutely destroyed.

[Trevor]

Tony, please consider.

The pressure gauge you have purchased appears to have only one point of connection and therefore measures pressure above atmospheric, which means that without modification it will not do the job you have in mind.

Unless the intake airbox is placed at an advantages position and the car is in motion, there can be no positive pressure of any consequence within the intake manifold. Your experiment requires the measurement of pressure developed across a restriction from inlet towards outlet, rather than against atmospheric.

This could be achieved by mounting your gauge within a rigid transparent container so that it can be viewed, with the existing inlet brought to the outside, and with a second connected to the interior of the container. This arrangement could provide two connections and a means of pressure measurement between the inlet and outlet, of any anticipated point of restriction within the manifold, at various engine speeds and load.

Alternatively you could use a sensitive vacuum gauge and measure the negative pressure at the point of entry and exit of the restriction and make a comparison. However this method would not be as efficient.

[Trevor]

Originally Posted by TomsSVX

I have been suggesting in fender cone filters for a reason.

- The stock airbox is a "cold air" already. it feeds ambient air from the fender already so a CAI is not going to improve air temperatures.

+ the reason i suggest an in fender cone filter is that it will draw the same ambient air as the stock air box... BUT... it smooths out the intake track. The stock airbox is like merging a 6 lane highway down to 2... Its gonna slow velocity down. It creates "dead spots" in the intake which during high rev's and high flow will become an obtrusion. The in fender with a cone filter creates a smoother track for the air to flow in and decreases turbulence.

Thats the reasoning behind them for me.

Tom

I would suggest that the existing filter and associated space, is the point at which a tuned length commences in accordance with the OEM design criteria.