matwey

Tried searching again. No luck. I have the super mega flow (same as Mahjik's). Best place to buy filters? Last purchase I made was from NOPI.

Mahjik

iTrader: (1)

http://www.importparts.com/shop/inde...sort=2a&page=3

matwey

http://www.nopionline.com/nopistore/...TOKEN=92185749

They were $15.50 here. Guess I'm sticking w/ NOPI. Thanks again Mahjik, always w/ an answer .

Mahjik

iTrader: (1)

Good deal. To be honest, I didn't get mine from there. I bought about 4 sets from a local ricer shop for about $50 a few years ago. Make sure to oil them before they are installed.

riptor

1. what oil to use..
2. do they make them for the rs intake..or are these the sameones..?

Mahjik

iTrader: (1)

Any oil will do. With foam filters, it's the oil that does the filtering, not the foam itself. However, using REAL filter oil is the best bet. Just go to a motorcycle shop and ask for filter oil. They will have some (as most bikes use foam filters).

I'm not sure what the RS Intake filters look like (when not installed). If they are a circle when flatten out, then yes those are the same ones.

Force13B

iTrader: (19)

You can get the K&N oil for pritty cheap from what i remember, comes in a arisole can to easy to apply.

matwey

WHOOPS, never oiled mine. Do you oil it like you would a 2 stroke racer? LOTS of oil?

Mahjik

iTrader: (1)

Lots of oil and work it through the filter with your hands. I would suggest using some disposable latex gloves as real filter oil is some sticky stuff (i.e. to catch stuff ).

This is the main reason people think foam filters suck is because they never oil them. Without oil, they aren't much good.

RoadRaceJosh

Foam filters also suck because they don't flow nearly as well as a cotoon gause filter. Why KHS and other Japanese companies make and sell this garbage is beyond me. Read anything David Vizard has written on air filters and you'll see real flow numbers and real filtration efficiency and see that foam doesn't cut it on either.

crazyrx7

I thought that the HKS filters weren't supposed to be oiled. Where does it say other wise?

R.K.

riptor

ive never olied mine...lol when i took the off yesterday(isolating turbo noise..weird squeeking sound..driving me nutz) they were kinda brittle and rough..didnt feel them before they were installed cuz i didnt install them. but i will look for some oil for those bad boyz tomorrow...wouldnt want my turbos to get hungry allof the sudden.

Mahjik

iTrader: (1)

Those tests (or really that one test) are BS. There is one test which is all over the internet, and if you actually read the full article you see that the people reporting the test didn't do the tests themselves (as they wonder if it's a PR stunt to get lesser known companies more attention since HKS and Blitz still out-sell all the others around the world). The filtration test DON'T mention the use of oil on the filters. Without oil, the foam is basically useless.

Trying blowing through a foam filter and see how restrictive it is...

Don't believe the internet hype....

That's just basics for foam based filters. Any foam base filter should be oiled as it's the oil that traps the smaller dust/dirt particles.

oorx7

iTrader: (2)

How often should the be re oiled?

Mahjik

iTrader: (1)

Basically, when they are dried up. I just usually replace the filters themselves once a year (every spring when it comes out of hibernation)..

matwey

doesn't HKS say to replace them every 3k miles? Or is that w/o oil?

Mahjik

iTrader: (1)

I have no idea. I never read any of the HKS instructions or anything when I got mine. I just inspect the filters when I do my normal car maintenance and replace when necessary. I would recommend "replacing when needed" rather than trying to pick a certain mileage.

riptor

ok..i cant find this squeeking noise..it sounds like its coming from the turbo...but i cant seem to hear which one... can i take my filter off ,while the car is running just to hear which one it is....with out negative affects..?

Mahjik

iTrader: (1)

Sure, I just wouldn't drive around much without it.

RoadRaceJosh

It's not internet hype. It's real testing done on a flow bench by the author and published in his own book. No advertising, no unverified claims and no BS. David Vizard supports all his assertions with his own documented testing. Vizard has tested paper, foam, and gauze filters. Paper gets the dirt out, but is restrictive and gets more restrictive quickly as dirt builds up. Gauze gets slightly less dirt out than a good paper filter, but flows much better clean than paper and doesn't plug up nearly as fast. Foam doesn't filter out much but rocks and bugs when dry and is still more restrictive dry than gauze. Oil the foam and it filters better, but looses even more flow to a gauze filter.

Mahjik

iTrader: (1)

If that's the book he did which was published back in '96, there have been tests using the 'current' crop of air filters.

Anyways, it also depends on the type of foam filter. Single stage foam filters flow exactly like gauze filters. It's the double stage foam filters that don't flow as well:

http://www.bobistheoilguy.com/airfilter/airtest2.htm

RoadRaceJosh

Yes, and now the story is which cotton gauze filter is best not if they are better than foam. Foam is still second rate at best for restriction and worse for filtration.

That's good application specific data, but not especially useful for comparing filter media for flow restriction. The biggest thing it shows is how little the filter itself restricts the airflow on a bone stock Miata with a stock airbox. The Miata filter is generously sized, but the factory Miata airbox is restrictive.

Mahjik

iTrader: (1)

Huh?

I wouldn't say "worse", but that's subjective. The extra 2-3 particles a gauze filter picks up over any other filter isn't going to make a hill of beans difference. People have been using foam filters for years before gauze filters made it mainstream.

While gauze filters are good, for automotive applications it really just doesn't make that much difference. A foam filter will do everything that is needed if that's what the owner chooses to use.

Hmmm, ok. I guess a more recent experiement that doesn't conform to an mid 90's book isn't useful? mmmkay.

If you want to use gauze, so be it. However, if someone wants to use foam, what does it matter to you? Answer, it shouldn't.

RoadRaceJosh

You mentioned "The current crop of air filters." The current crop of best air filters is now a selection of cotton gauze filters not just K&N v everything else.

Foam does not filter as well as gauze. Foam does not flow as much as gauze. If you forget to oil the foam like many of the folks in this very thread and it filters very poorly indeed.

When the test was performed is largely irrelevant as long as the test still applies. We are still debating foam v cotton gauze and neither type has changed significantly in the last decade so the test is valid. What is clearly relevent is the limited scope of the test you cited. The stock Miata filter element is generouly sized for the application so the filter restriction difference between filter types is slight. Put the same size filter on something making more power and the flow/restriction differences will be greater. This is why a flow bench test with filters of equal area is a better test than running 6 filters on one bone stock car that already has a generously sized air filter.

Let's compare filter area of the test Miata with an HKS equipped FD shall we? FDs make almost exactly twice as much power stock as a 1.8 Miata at 255/128hp respectively. A round foam HKS twin filter for an FD is 150mm. There are two filters and they are almost a hemisphere, but not quite so I'm being somewhat generous here. For the sake of discussion we'll assume that we have a 150mm sphere worth of filter area. Area of a sphere is 4śR^2. 4*3.14*7.5cm^2= 706.5cm^2 of filter area. The stock Miata filter is right about 25cm*15cm or 375cm^2. As you can see the stock Miata filter has more surface area per horsepower and lb/hr of air than an otherwise stock HKS filter equipped FD. Bump the hp in your FD and you end up with even less filter area per hp than the Miata. Repeat the Miata test on a modded FD and you will see greater differences in restriction.

You said I was quoting internet hype, which is completely untrue and your source is no better than mine. So after all this we have you happy with buying HKS filters every spring and me with buying a K&N once and cleaning it every few years. Whatever floats your boat!

With the rate at which FDs consume engines from failures other than poor filtration you are absolutely correct to say the foam is just fine as you'll never even see the abrasive wear before popping the motor.

If anyone wants to see real filtration in a severe environment look no further than any desert race and tell me what type of air filters are used.

Mahjik

iTrader: (1)

Which is the whole point of this thread help debunc of lot of "foam filter" myths. Most people never realize that a foam filter without oil is basically there only to stop large debris. In most cases, that's fine. Heck, there are many single turbo guys who don't run filters at all.

Limited? Hmm, I guess creating a controlled test is limited.

That test shows exactly what the manufacturer is sselling, not just a filter element on it's own. Sometimes, and most cases, that can be two COMPLETELY different things.

That would be like testing home ventilation system filters and then saying that's how it's going to react on your car. Their goal was to test what was offered for a car and see if the manufacturer claims were correct. Obviously, they found the claims to not be completely accurate with their testing.

There are many online results of filter tests. I don't plan on spending my time posting links. That's just one of the many, however, one of the more comprehensive which is why I posted that one.

There is no doubt that gauze is a good product. However, there are a LOT of misconceptions around about foam. When developed/used properly, it can and is just as good (and in some cases better) than gauze.

Exactly, pick the right part for the right application. Driving a desert race, filtration & longevity of a filter becomes more of a concern.