K&N alternative

[94SHO_Norfolk]

I wanted to replace the stock paper air filter with either a drop-in K&N, or fab up a Uni foam pod filter into the stock airbox. Looked up some info on K&N's and Uni's website, and found the following. K&N has a drop-in tray filter, part # 33-2040, $54 retail. Uni has a pod-style filter that I could've mounted in the airbox lid, around the metal intake piece with the screen on it, part # UP6350ST (3.5" ID x 5" diam x 6" long), $37 retail. I checked the local auto parts stores around here, and none of them carried the K&N filter, it's a special order. So I went down to the local motorcycle parts store, that carries a bunch of Uni filters, but they didn't have this particular filter either. So I thought of another alternative, and this is what I came up with.

I removed the stock paper filter and took it inside the motorcycle parts store, and was comparing it with some of the Uni foam tray filters they had. Well, I saw this one on the shelf that looked pretty darn close in length and width to the stock filter, so I pulled it down and set it on the floor, next to the stock paper filter. To me, they seemed to be the same in width, but the Uni filter (part # NU-4110, $32 retail) was a little shorter in length, plus it had rounded corners, not straight ones like the stock filter. I decided to roll the dice and buy the Uni tray filter, and see if I could get it to work.

http://i803.photobucket.com/albums/yy319/socal1200r/1994 Ford Taurus SHO/UniFilter1.jpg

http://i803.photobucket.com/albums/yy319/socal1200r/1994 Ford Taurus SHO/UniFilter2.jpg

So I get home and start the process of seeing if this Uni filter would work. I pulled the lid off the airbox, removed the stock filter, and set this Uni filter down on top of the airbox bottom. The sides were wide enough to rest on the airbox bottom, but it was a little thicker than stock, so I had to move the Uni filter towards the front of the airbox, in order for the rear of the airbox lid to angle into its fittings on the airbox bottom, which ended up leaving a small gap along the back of the airbox.

I didn't think this was a good idea, so I decided to cut up some window screen mesh material I had, and used the stock paper filter as a template. Before I did this though, I oiled the Uni foam filter with some regular cooking oil spray I've used on other Uni foam filters, and let it soak in. I set the stock filter on top of the mesh, and cut about 1/2" wider all the way around. I then took some paper towels and soaked up any excess oil from the Uni filter, and walked back out to the car. I put this mesh under the Uni foam tray filter, then wedged it inside the airbox bottom, so the mesh was now covering any gaps, then put the airbox lid on.

The car started right up, didn't throw any codes, and shouldn't oil up any sensors along the intake tract since I soaked up any excess oil with the paper towels. I took the car for a short road test, and all is well. It sounds a little louder on the intake side, and seems to pull a little harder, especially above 4000 rpms, but that's just my seat of the pants dyno.

In any event, I wanted to pass along an alternative to the typical K&N drop-in filter "upgrade". From my experience with using K&N oiled gauze and Uni oiled foam filters on motorcycles, the Unis seem to flow more air, and filter just as well, if not better, than K&N's. Plus, they're washable just like K&N's, but for most applications, are considerably less money.

 

[lowc]

i use the k&n drop in and have had no issues i pull it and clean it evry 2nd 3rd oil change

 

[Shoaz]

What problem are you trying to solve by using something other than a paper filter?

I have some pics from a microscope showing the size of the holes in a K&N. You can see them if you hold one up to the light. They're pretty big, and they let big particles through. A paper filter under the same magnification has no visible holes.

I use paper whenever I can, even at the track.

 

[94SHO_Norfolk]

What problem are you trying to solve by using something other than a paper filter?

I have some pics from a microscope showing the size of the holes in a K&N. You can see them if you hold one up to the light. They're pretty big, and they let big particles through. A paper filter under the same magnification has no visible holes.

I use paper whenever I can, even at the track.

I guess I'm a believer in the urban legend that stock paper filters don't flow or filter as well as an after-market filter. Found a couple of websites that shed some light on the subject:

http://www.roadkill.com/~davet/moto/air.filters.html

http://www.ibmwr.org/otech/airfilter.html

I suppose one can draw their own conclusions regarding paper versus oiled foam versus oiled gauze. But in my experience on motorcycles, oiled foam was the better choice (higher air flow and better filtration), MUCH less expensive than a K&N oiled gauze, and easier to wash/reoil.

 

[deercrusher]

I'm with Shoaz on this. I had a K&N filter on my sho but my next sho will not be getting one. They do provide maybe a LITTLE more power - but I will be using paper from now on as I do not want larger particles finding their way into my motor. Aftermarket filters and intakes can be just like snake oil for some cars. They promise the wold but you need to look at what you're starting with - some cars didn't have bad design's on the filter/intake. Obviously there are some exceptions - such as the 4bbl rochester equiped chevy caprice from the late 80's. Alot of power to be made there.

 

[Shoaz]

Considering the difference between a paper filter and no filter at all is nearly in the noise on a dyno, there's little to be gained by using a K&N, IMHO. There are, however, some obvious downsides in loss of filtering efficiency. Plus the MAF fouling issue from the oil, and I just think they're a complete waste of money.

 

[94SHO_Norfolk]

Yup, a thread on air filter types is like a thread on tires, dino oil versus synthetic oil, etc. The intent of my original post was to offer an alternative to a K&N drop-in tray filter, for those of us who are inclined to do away with stock paper filters.

I actually think the airbox setup on the SHO is pretty decent, certainly better than most "cold" air intakes I've seen (which IMO, is actually a "hot" air intake, since the cone filter isn't sealed from the rest of the engine compartment, like the stock airbox is).

I've never really been a fan of stock paper air filters in any vehicle I've owned, and have ended up replacing them with something like a K&N or Uni foam filter. Depending on the vehicle, a K&N or Uni filter will pay for itself after about 2-3 air filter changes using a stock paper filter. And from what I've read and experienced myself, a Uni foam filter flows more air and has the same, if not better filtration, than a stock paper filter, and is a LOT cheaper than a K&N.

Again, for those of us who are inclined to do away with stock paper air filters, a Uni foam filter is a good alternative to a K&N.

 

[_JR_]

Since the filter can of worms has been opened...

It all depends on where the SHO is driven and in what conditions for someone to be weary of using a filter that is high flow (less filtration ability) versus the oem paper filter.

This is probably one of those things like type of oil or oil filters. Lots of opinions and some facts.


I've never heard of a foam filter, so thats pretty cool. Are they mainly used in motorcycle applications?

 

[luigisho]

I don't like oiled filters. I've seen too many MAF elements gunked up to trust them very much. I used to run K&N and returned to paper after a few years.

 

[94SHO_Norfolk]

... I've never heard of a foam filter, so thats pretty cool. Are they mainly used in motorcycle applications?

Here's a link to Uni's universal foam filter listing.

http://www.unifilter.com/online catalog/universal.html

The best ones are the dual-stage filters, which have a coarse outer "sock", and a denser "inner" sock. I've used these on a few vehicles I've owned.

http://i803.photobucket.com/albums/...Uni filter install 6300 AST/UniInstall4cs.jpg (Uni dual stage filter inside a Jeep Comanche airbox)

http://i803.photobucket.com/albums/yy319/socal1200r/DSCN0122s.jpg (Uni dual stage filter on a '97 Saturn SC2)

http://i803.photobucket.com/albums/yy319/socal1200r/DSCN0369s.jpg (dual Uni foam filters on an '07 Saturn Sky)

As you can see, there are numerous applications where these Uni dual-stage foam filters can be used. From something as simple as replacing the pleated gauze cone filter that comes standard in a lot of intake kits, to fabbing one up to work inside a stock airbox, like I did with the Jeep Comanche and SHO.

Again, just offering an alternative to the K&N style oiled gauze filters out there. For most applications, they're considerably less expensive than a K&N. Good point about over-oiling, I've heard the same thing about fouling sensors. The easy fix is to NOT overoil them in the first place, which with some practice, one can get the hang of doing pretty easily. I've used regular cooking spray to oil my filters, then dried up any excess with paper towels, and that seems to work pretty well. Don't use olive oil spray, it's WAY too slippery! The brand name filter oil is too expensive IMO, and cooking spray seems to work just as well. I spray the outside of the filters, then massage the oil into the foam, let it dry for 5-10 minutes, then take some paper towels and massage the filters again, taking up any excess oil.

 

[1993MTXSHO]

:woo-hoo: for the kick ass sound of an aftermarket setup, or even a drop in K&N!!!

 

[Shoaz]

Wish I had an example of a foam filter to put under the digital microscope. Hard to beat paper for filtration, though, and the microscope makes it pretty obvious why. There's a reason the manufacturers design them in.

 

[94SHO_Norfolk]

So I'm having a hard time falling asleep tonight (it's midnight), and an idea pops into my head regarding a better fit for the Uni oiled foam filter tray I put in. I originally cut a piece of window screen mesh using the stock paper filter as a template, put it under the Uni filter, then wedged it inside the stock airbox. The only down side to this was the two airbox halves didn't fit as snug as before, because the filter edge wasn't wedged between the top and bottom airbox halves, and the front airbox clips really didn't have any tension on them.

So I'm lying there, thinking about a better way to do this, when I thought about putting some window screen mesh over the inlet tube up in the fenderwell instead, or covering the airbox inlet at the fenderwell? I pop the hood on the car, unplug the sensor, and move the upper airbox cover and TB hose out of the way. Looking in the hole in the fenderwell, I see the end of the inlet tube, and feel my hand around it, and it appears to be sealed, so all I have to do is cover the end of that tube, and I should be good to go. So I cut some window screen mesh, put two zip ties together, work the mesh over the end of the tube, slip the zip tie over the mesh, make sure I've got mesh completely covering the hole opening, then cinch down on the zip tie. I checked with a flashlight, and the hole opening is completely covered, with no gaps.

So I plug the sensor back into the airbox lid, reconnect the intake tube to the TB, place the Uni filter on top of the airbox bottom towards the front, then put the lid down. It took me a couple of tries, because the filter kept tilting inside the airbox, but I finally got the lid down so it's wedged between the two halves, like the stock paper filter. The airbox is nice and snug now, with some tension on the two clips at the front, which it didn't have when I had the Uni filter inside the airbox bottom.

So I've got the inlet tube opening in the upper fenderwell covered with mesh, so that should keep the leaves and other debris out of the airbox. And the Uni filter tray is now wedged between the upper and lower airbox halves, making it fit nice and snug, so I think that's a much better solution.

I might have to take some pictures of this, and post them in here, but hopefully I've been descriptive enough for folks to visualize what I did!

 

[firebat45]

I'm a believer in the stock filter, I've seen the dyno tests and I don't think there's anything to be gained from a "better" air filter besides intake noise (not that that's a bad thing).

However, I used to be big into nitro RC cars, and every single one I've seen uses a dual element (coarse outer and finer inner, only the inner is oiled) foam air filter. I've seen these things get incredibly dirty, encased in mud, and they still keep the motor clean. These little engines are also quite high performance (5HP out of a 0.46 cubic inch "big block", at 23,000 RPM) so I'm sure they're using the best filter for the job. That's the nice thing about nitro RC, they're such a small scale thing that you can afford to use the best materials for the job, whether it's titanium con-rods, carbon fiber chassis, lexan bodywork, or a foam air filter.

Just my 2 cents...

 

[swami]

i have one of those Fram Airhogs that i bought off fleabay NIB. i could tell a diff in the butt dyno when i installed it.it is not as ruggedly built as a K&N but cleans and reoils like one and worth the money. there were 2 in the box and i would sell one for $10 plus ship if interested. everytime i have installed a K&N or clone i could tell the difference.HTH

 

[93rev2sev]

for someone to be weary of using a filter that is high flow (less filtration ability) versus the oem paper filter.

I have nothing useful to add so I'll just correct (english warden) your very common mistake:


You get WEARY from doing the same thing for a long time.

You get LEERY when thinking about trying something new...that you aren't sure of.

FYI.