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I'm think of buying a stock air box from a wreck & gutting it & opening up the intake part of it to where the engine can breath. I currently have a K & N filter in it now. What would be the best dry filter to go with? Will I notice any increase in Gas mileage in doing this? I'm planing on using 4" dryer aluminmun tubing from the air box to the headlight area & sealing everything with silcone & the metal furance tape.any help or comments on this will be appreciated. Thanks in advance. Johnny
Last edited by Johnny_r; 06-15-2008 at 11:51 PM.
Reason: adding info
I thought about doing the same thing, but ended up just insulating the air box and sticking with the stock filter. Don't buy a box off an '04; it's different from '02-'03. Let us know how it turns out and if you notice any difference with the larger snorkel.
Black 2004 Explorer XLT Sport 4.6L as my "boat hauler" for Lake Havasu/Lake Mohave runs
The corrugated tube is bad for airflow, you'd be better off using straight pieces of PVC or exhaust pipe. Companies like AEM make flanged, dry filters if you want to stay with a clamp on cone filter (which I would).
Took the air box apart today & where it intakes from the headlight to the air box is real small & with the headlight in the way there is no way it can get enough air. The opening in the radaitor support is real small too, so I took the snorkle off & it just suck in from the same area the opning in the box is slightly larger with out the snorkle in it, I know it can get some hot air during start up & idling, but at least it can now get air. The mass air flow sensor is also a major restriction it is only 2 & 7/8" round so the rubber tube from the throttle body to the air box doesn't really matter. I also don't see where a K&N performance cold air kit would really help that much because it uses the stock mass airflow sensor. To me Unless someone makes a better system that gets its air from someplace else there is very little improvement for the 2002 Explorer unless you want cut on your radaitor support.
If your using the E0945 k&n filter, the FIPK filter is much larger for more surface area. Basically the more surface area, the less the restriction of the media matters, so the bigger filter makes less vacuum inside the filter.
The MAF is about as large as you need, velocity is what your after in a cold air kit. Removing the baffling that keeps the engine quiet and getting the air's speed up fills the cylinders faster. Think of it like pressure, if you blow through a straw it's hard, if the straw has bends it's even harder, if you blow through a piece of 4" pvc you don't get much effect, now blow through a 1/2" pipe and you can spit a piece of tater across the room. Does this help alittle, I don't know how to explain it better.
There is a hose coming into the tubing that goes to the mass air to the throttle body, would I just need to drill a hole & put the rubber bushing in & attack it about the same place as it is now? Also do you know the size of the throttle body opening? I would need a silcone adaptor to use the 4" sewer pipe? also where can I get a adaptor to connect my mass air flow sensor to another pice of pipe, I know how i can build a heat shield for the cone filter.
The TB is about 65mm or close to 2.5" dia. You don't have to use silicone, I once used rubber sewage couplers from Ace. If you must Vibrant makes a nice selection fairly cheap, vibrant is available through DriverFX and any advanced auto parts that has a keystone catalog.
You should have the same MAF as I do, the housing is calibrated for the flow, if you change the size of the chamber, then the computer will not receive the correct air volume. One side has about a 2.5" round flange, the other side has four bolts. In K&Ns kit, there is a plastic bushing to bolt to that end of the MAF, and the filter clamps over this bushing.
Today I opened the airbox up to 4" & used a piece of Sewer pipe out to the rad. Support, it made a big difference in throttle responce & power I also changed the oil to Moble 1 5w30 Sythetic with a motorcraft oil filter i can tell that my engine seems smoother so far i haven't got any codes Going to take a trip to Ky next week & i'll find out if I've made a difference in gas mileage, also I going to find out tommorrow if my local muffler shop can bend me some 3" pipe to go from the throttle body to the mass air flow sensor with out knicking it that should help too.
Last edited by Johnny_r; 06-23-2008 at 08:27 PM.
I've found out from personal experience that the common pipe benders can't do very tight turns. More so when they are less than a foot a part. You might have to do some reconfiguring to make it work, but it's a nice way to go. I'd suggest getting SS or actual aluminum pipe and not just aluminized if you wish to polish it up.
I changed out the 4" sewer pipe today & went with a piece of 4" stainless I had it cut just to fit & used a seam sealer to make sure that it doesn't leak around the airbox I had a flange made on the pipe so i could rivet it into the airbox for a good fit, I'm thinking of cutting the radaitor support so that 4" will fit into it, that way it can get a full 4" of air from behind the headlight, I like the way that the factory airbox has drains built into it that way if i do pickup some water it should drain away. I can tell that I have a lot better throttle responce with the 4" stainless pipe. I haven't changed anything from the airbox to the throttle body the factory pipe is short & seems to be around 3 & 1/2" inside.
If the run is long enough, water drops should fall to the bottom of the pipe before reaching the filter. However, if you make a small hole near the filter, it will have a vacuum and not allow water to drip out. I had this problem on the A/C unit of my old shop, the A/C could pull enough air through the 3/4" drain, that the water wasn't allowed to flow out and the A/C condensor kept flooding. I am not sure if that was only because of the long run of the drain or if the problem was just as bad near the unit, but it's something to consider. Perhaps just being a long pipe and angled down just slightly will work.
Chevy's spec for water on the WS6 hood was just a half height baffle behind the scoops of the hood. Since your pipe is about twice the size the TB, you could put a baffle in some where.
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