Air box opinion

[Jake Jackson]

i was curious obout how todrill the air box. I was wanting an opinion about hich way to drill he air box.
Should i do the swiss cheese method, the front side removal method, lots of smal holes on each side or a jus on designated sides.

This is just going to be a temporary change until i get the "tru rev" system but ithuht i would hae some fun first.

Thanks

[RTStork]

I cut a big square out of the front of mine but if you insist on the drilling holes method, I would just drill the front. This keeps the filter pulling the cooler air from behind the headlight.

[Sport (no trac)]

I second RTS' opinion. This is exactly what I did to my '01 Sport and I am very pleased with the results. Try it and pick up a high flow filter. The combilation of the two will give you only slightly less performance than the KKM and for a fraction of the money. Unless you spend all of your time driving at the top of the tach you won't notice the difference between the cut box w K&N and the KKM. The cut box also allows you to use a stock paper filter in the winter when sand is blowing around or when offroading.

Even the best free flowing filter lets in a ton more junk than the worst paper filter. Being able to use a paper filter in a situation will protect your engine. Flexibility is key for a daily driver.

[aldive]

Originally posted by Sport (no trac)
Even the best free flowing filter lets in a ton more junk than the worst paper filter. Being able to use a paper filter in a situation will protect your engine. Flexibility is key for a daily driver.

Is this an opinion or do you have some data? Please share if you do.

Thanks....

[Jake Jackson]

thanks guys i think i will try to do the cut air box method but i just have one more question. do you cut off theentire front of the box or how do you do it exactly.

[RTStork]

I wish I had pics but I don't so I will describe it. I removed the airbox from the engine bay. On mine, you have to unscrew the MAF from the back of the air box. Next you pull the airbox out. Its held in with some grommets on the bottom of the airbox. Just pull upward on it and it will give. You won't break anything, but it will require a hard pull to get it out. I measured how far my K&N hung down in the bottom part of the airbox. I cut a big square out of the front of the airbox. Here's how I did it: I then used a Dremel and cut from the very edge of one side, all the way to the other, and all the way to the bottom. Basically the whole front of the airbox is gone, except for about an inch or so at the top to keep the K&N covered. Thats it. I hope it makes sense. If not email me and Ill try to explain some more. I don't know what I would have used if I didn't have a Dremel. I guess you could use a jigsaw but I'd try to borrow a Dremel or go buy one. You'll find many more uses for it down the road. Hope this helps!

[Alec]

A properly oiled S&B or K&N filter DOES NOT let in more stuff than the paper filter. I've been in all kinds of "high-junk" situations with my KN FIPK and have yet to find dust or anything in my air intake tube or anywhere in my intake tract. When I installed the KN, I had to clean everything out after 2 years with stock paper filters. I've had the KN for 3.5 years without any problems.

So if you think you'll be in worse situations than Texas windstorms, Hill-country mudbogs, or Moab dust clouds, maybe you'll test the KN more than I have.

[Sport (no trac)]

RTStork, funny, that's the same exact thing I did with mine, right down to measuring the filter's extension into the lower box. The only other step I took was to sand the newly cut edges for a factory look.

Al, I 'aint no skientist, but I guts a test for ya. Yo, Alec, you betta pay attention to this too...

If you read the various tests, K&N and the rest swear that their filters clean as thoroughly as a paper filter, but do so more efficiently. Tell me something, does that make sense? In order for air to flow more freely, there have to be either more and/or larger passages for air to pass. This must mean that the possibility for dust, etc to pass through must be greater in the free flowing filters. I did find a scientific study that alluded to this also, but I don't remember where it is, so I can't refer you there. I also had this very same discussion with a buddy of mine who also has an X with a K&N filter. I couldn't refer him to the test I found either, so we did our own.

His X is a 96 with a conical filter set up, and mine is an '01 with the panel filter. Unfortunately I don't have a K&N filter so I used the factory airbox from my '88 Mustang 5.0 which does have a K&N and is similar to my X's.

What we did was remove he air boxes from the MAS sensors and installed paper filters in each. To the MAS end of the box we installed a shop vac with duct (that's duct not duck!) tape between the vac hose and air box. This way the sticky side would catch any pass through. We also put a wide and heavy strip of rubber cement on the inside of the air box after the filter which was also planned to catch any by-pass through the filters. Next grabbed a large box, one big enough to hold the air boxes and we put about a cup and 1/2 each of sand, sugar, pepper and baby powder (hey, you use what ya got) to represent the various sizes and consistencies of the debris your X might encounter on the road. Next we put the air boxes in the box, turned on the vaccuum and shook things up. What do you think we found?

The duct tape caught nothing in either case, which I assume is because the glue is not tacky to the touch. The rubber cement, on the other hand told a better story. The strip behind the paper filters was very clean, with only traces of baby powder. The K&Ns, on the other hand showed much more baby powder as well as traces of salt, sand and sugar, well at this point we couldn't tell the difference between the sugar and salt, but there was some on the rubber cement strip nonetheless. Now, there wasn't a lot, but there was some. Take from this what you will, but it was enough to satisfy me that there is pass-through. For your own test, hold the K&N up to the sun and tell me what you see. I noticed pinpoints of light.

There is no denying the power advantages of the K&N filters, but the power comes at a price. Alec didn't notice any junk in his flow pipe, but maybe thats because it was inhaled into his cylinders. Matter of fact, if you do a search on this topic you will find someone who said the exact opposite and puts his stock box in when he goes offroad.

As far as over-oiling the K&N to prevent pass-through, well, some of that oil gets sucked in and becomes a deposit on the MAS and changes the sensor readings. There have been plenty of posts on that also.

[Robert]

It all depends on the size of the particles the filters let in. As an analogy, lets say the paper filter has 100,000 pores to let particles in. Lets say that those pores are 5 microns in diameter. Now lets say the K&N open air filter has 500,000 pores, but they are only 1 micron in diameter. Would you rather have 100,000 pieces of 5 micron debris going through your engine or 500,000 pieces of 1 micron debris going through? If you get the size down to a small enough size that has no effect on the engine, then it doesn't matter how much of it you let in (within reason). It only takes a few particles that are a bit too large to cause more wear on an engine. It is possible to let in more air without letting in more dirt if the filtering is small enough and there is enough surface area.

[aldive]

Originally posted by Robert
and there is enough surface area.

The real key to why conical filters "work" so well in air flow.

[Sport (no trac)]

Robert, I agree with you, but due to the results of my test, which were far from scientific, tended to suggest the opposite was true, or at least that the paper might have 100,000 5 micron pores, but that the K&N filter had 500,000 5 micron pores. Of course, I have no idea how many or what sized pores in either case, but I do know what I saw, and that was that more debris flowed through the K&N panel and cone filters than passed through their paper equivalents.

[Retardriot427]

so your saying if im going in the mud i should keep the stock paper filter on and make some holes in the air box?
the problem is now that i go through mud/water holes and water/mud gets sucked up through my air filter and will kill my engine

[jimbo74]

Originally posted by Retardriot427
so your saying if im going in the mud i should keep the stock paper filter on and make some holes in the air box?
the problem is now that i go through mud/water holes and water/mud gets sucked up through my air filter and will kill my engine

mud and holes in airbox bad

street and holes in airbox good

[FORDisKING]

I'd rather take my bone stock airbox w/ panel K&N through mud (or any other ENGINE HAZARD) than ANY CUT BOX. The paper filters for my 2002 (4-Door) suck. I purchased a panel and IMMEDIATELY noticed that my 5-speed auto. doesn't shift as often, not to mention better gas mileage. I wouldn't even cut the box.

Buy a conical kit, use that on the street and use the stock going off road. That is more sensible than taking a CUT airbox off-road.

Jay

[JDraper]

I would disagree with not wanting the drilled airbox offroad. One of the advantages of drilling the airbox is that water and mud will not collect in the bottom of the box if you do it right. The stock airbox has one fairly restrictive air intake, and several small holes in the bottom for drainage. If you are out mudding and ingest mud into the airhole, the drain holes in the bottom of the box will clog up, and the box will begin to hold water (since the air inlet is on the side of the box). Do this a couple of times, and you'll have mud and water sloshing around in there just begging to be sucked into your intake.

If you plan how you cut your box so that you limit how much water can be splashed in, I think you'll be less likely to toast your motor. I used a 2.5" hole saw and cut a hole in the bottom and one in the fender size of the box. Both holes are protected by body parts that prevent water from being splashed in, but will still let mud drain out. I have had my X buried pretty deep in some nasty stuff at Paragon, and haven't sucked any in the intake. The box does show signs of mud having been in it, but never more than about an inch deep.

Naturally if you submerge the box, it won't matter what you do short of a snorkel, you're gonna suck water into the motor.

I would submit that the open conical filters are far worse for offroading because they sit out in the open and are VERY susceptible to being splashed. At least with the airbox in place, there is a considerable amount of protection for the filter.

[FORDisKING]

I would submit that the open conical filters are far worse for offroading because they sit out in the open and are VERY susceptible to being splashed. At least with the airbox in place, there is a considerable amount of protection for the filter.
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This is what I said in the first place.


Masher

[zavetsky]

The other issue I often wonder about is how much do you REALLY gain (or lose) using an open element style like the cones....

It is a scientific fact that colder air nets you more power than hot air.....it also a fact that MORE air is better.....

So does the HOT air from under the hood that is sucked in thru a cone really do any good or does the extra volume of it make up for the downside of the heat?

Open elements that are in hood scoops or out from under the hood net a LOT of gain, but I have nebver been convinced if the element is simply sucking in hot engine air.....and under the hood of my Explorer, it is MIGHTY hot and cramped...I cant see how flow OR performance is really helped by that much.....

I had an open element on another vehicle and I think the biggest "gain" was in a cool sound from the engine bay....the sound of the carb sucking in air.....I dont think I gained much more than that....

I run a K&N panel in my stock box and seem to have picked up a little extra oomph...

[Retardriot427]

so whats the good setup for muddin short of a snorkle

[FORDisKING]

The air drawn in is hot to warm by nature. The drag of the vehicle heats up "the streamline"!? Come on, I fail to see the point of Mudding, or any extreme off-roading short of two-tracks, with a Cut-air box. That is THREE steps closer to vapor lock as far as I'm concerned. On the street it's fine (the cut-box).

Jay

[Robert]

Once I get above 10 MPH, the airflow going past my intake air temperature (IAT) sensor is within a few degrees of the outside air temperature. Tests that I have run with both my stock air box versus my K&N FIPK have shown that the temperature difference is negligible once I am at or above 10 MPH. I leave my FIPK on when off-roading and believe me the deserts here in Arizona are quite full of dust. I just make it a point of cleaning my filter whenever it starts to look too bad. Another advantage to my open element is that anytime my hood is open, I can see how dirty my filter is. Before with my stock box, it only got looked at when I made the effort to open up the box which wasn't every time I opened the hood.