Amazon.. Its hidden though. Poorly named, and a terrible photo, but this is indeed the AIS system. I bought it. $185 and free shipping if youre a member.



Replacement filters are $67

 

Thanks Trey!

I added a 6637 earlier in the summer this year. I miss the stock box quietness.

I found the blueprint for enclosing the 6637 and have a A/C duct work builder friend. May have him cut out the walls for me and try to quiet it down first.

 

Y2KW57 - That was a fantastic post - I repped ya. I don't suppose you have the flow data from other intakes, do you? Not for this thread, but another recent one.

Guys, that AIS was sold before my new intake arrived... three times over. It's now sucking in the clean air of Bend, OR. The comment was "...you where not kidding about the sound or lack of sound. I have had an open element for close to 400k and am absolutely tickled with the new found peace and quite."

 

This thread has got me so fired up on the AIS that I just ordered it from RockAuto for $179.95 shipped.

I hope I will be able to see the benefits from switching from the stock box.

BTW.....how long do these filters last? I guess I can try to search for the answer, but I thought I'd ask here first.

 

if you look back through this thread I think tugly mentions some real world mileage out of an ais filter. I just got one and I have no complaints. Fit perfectly.

 

What did you notice right off the bat after install? Did you mpg increase. Noise difference, etc.? Again, I can go searching, but thought you could give me some personal experience.

 

my trucks a pavement pounder,I plan on 3 years or 30k miles which ever comes first,although our company service trucks filters last about 2 months in dusty field conditions,with a couple careful cleanings in between.

 

I do have flow bench test data (somewhere?) for lots of combinations of air boxes and air filters for our application, but this test data is over 12 years old, and some of the aftermarket air boxes are no longer even manufactured, or were from companies that are no longer in business. And of the manufactures that are still in business, most have since changed (stepped up, I'd say) designs since these tests were performed.

At first I placed a lot of focus on the factory air box, and the revisions that brought incremental advances in lid seating, lid retention, and gasket sealing. Some of these revisions were so subtle, (eg. like the tab on the firewall side was lengthened a couple of mm) so as to be entirely inconsequential in terms of the flow and fouling balance of the filter media itself. But I was thoroughly infected with the enthusiasm of this cowboy like engineer from KTP who literally pulled me aside the second time I met him and showed me the ropes of all the improvements he had personally campaigned for.

Then I turned my attention to what drop in flat panel replacements best fit the idiosyncratic (some say idiotic?) sealing surfaces, especially in the areas of the gasket that were least compressed by clamps or tabs, and in the inboard corners most vulnerable to a banana like heat set.

Measurements got fairly detailed. Here's an example, recalling a couple of filters mentioned earlier in this thread: The overall height of the K&N 33-2138 gasket is .275", but really, the majority height of this gasket is actually only .210". The remaining .065" of height is just a skinny perimeter ridge with a root width of only .075" that tapers to .055" at the top. To put .055" in perspective, it may help to know that the diameter of an ink roller ball at the tip of a ball point pen is about .050". Wind blown road debris can be larger in size, and if that debris is hidden in the batter of the filter grease that K&N recommends applying on the gasket, it might displace that .055 sealing ridge when the lid is compressed by the spring clamps.

This is not an insurmountable problem... it just requires more attention to detail in thoroughly cleaning of all four mating surfaces at every re-oiling interval... the bottom and top of the gasket, the top of the box and the bottom of the lid. This tedium takes more time than most techs have to spare, which renders that specific filter gasket to be not as reliable in real world service when compared to a more compressible filter gasket with a softer durometer and a broader sealing mating surface with a rounded taper. So the critical scrutiny began long before the flow bench was ever powered up.

By contrast, the Wix manufactured Ford 1710 (superseded by the 1750) has a top-of-gasket lid sealing width of about .175", which is three times wider lid contact than the .055" of the aforementioned K&N. The root width at the base of the 1710 filter gasket is .490" (compared to .075" root width of the final sealing ridge of the K&N) that continuously tapers up it's .295" of height (.020" taller than K&N 33-2138) to the aforementioned .175" crown that contacts the lid. The thicker, taller, softer gasket of the OEM filters at least appears to be better at accommodating variances in the lid to box sealing, but then again, look at the photos above, where we still see some seepage intrusion over the ridge on the stock filter, due to issues with the lid closure.

Quite a few years have rolled by now, and the flow bench tests and comparison data collected back then was at one time interesting and useful for making a justifiable case to produce a better solution to address some of the lingering issues that were not fully licked with the OEM revisions. Once a better (but still not perfect) solution was developed, the most glaring issues were adequately resolved, and my data (and complaints) became obsolete.

Without dredging up mountains of arcane details and specific test data, I do still remember some overall observations from testing the air filter and airbox combinations available in the OEM, OE replacement, and entirely aftermarket iterations at that time (pre-AIS).

Here is the executive summary (if you are seated in the choir, you can skip reading #'s 1 and 2):

1. Garbage In, Garbage Out. This one everyone knows. But it is here as #1 because this basic concept influenced (and restricted) the choices of air filters and air boxes evaluated for testing (key word = boxes; missing words = open element). Feeding hotter air into the intercooler means getting hotter air out of the intercooler. There is only a limited number of degrees any given intercooler can drop the air temps for the short period of time the air has a chance to pass through it. Hot air = lighter air = less air density. Cold air is what we want, and why we put up with arm wrestling CAC tubing every time we need to do something in the engine compartment.

2. Idiot Proof. Even for the guy who pulls into the do it yourself car wash after mud bogging, and with a minute left on the last $5.00 worth of quarters he poured into the machine decides, "why heck, might as well power wash me motor" and proceeds to blast away at his unprotected paper element. This isn't said to condemn anyone's choice, but it is listed here as #2 to simply explain why only enclosed air boxes were compared on the flow bench, and not open elements. A certain standard had to be met for a better solution, and filter element protection was one of those standards.

Now, for the good stuff:

3. Proximity and angularity of neighboring structures to the air box inlet was highly influential to the flow rates measured. Higher than initially expected. A lot of flow tests had to be redone all over again, costing another full day on the bench (whose use was generously provided by a manufacturer who also used the data collected to develop another solution) upon discovery that the exact angle of rotation of the snorkel inlet, even when pointed straight up toward the ceiling, was not carefully noted relative to the wall nearest the flow bench machine.

4. A radial or circumferential seal with a constant torque clamp is the most repeatably reliable filter attachment method for the lowest cost. I didn't test open elements, but that is one of their strengths, that circumferential seal. There were several aftermarket fully enclosed airboxes that incorporated a full circumferential seal about the base of a conical or elliptical filter element inside the box. This makes sense, because of the lower cost and higher reliability of this type of seal. Their airboxes may have leaked, but the suction end of their circumferential or radial filter seal didn't, so the only harm was the intrusion of hot engine compartment air into the air box, not unfiltered air into the turbo. By comparison to the stock lid sealing system, these circumferential seals were more confidence inspiring. It was quite clear that a planar perimeter seal of a flat panel filter either needs a lot more attention in service, or needs a lot more attention in design.

While the observation in #4 above suggests that circumferential seals are "better" than planar perimeter seals, please keep in mind that this testing was limited to comparing AVAILABLE solutions that were already on the market and that were designed to fit the packaging constraints for this singular application back at that time. Many automakers use rectangular perimeter seal flat panel air filters without the problems that Ford had in this application. But there are some obvious mechanical differences in those other designs, which leads to..

5. Rock, Paper, Scissors. For lid retention on the air box, spring clamps trump fixed finger tabs. But screws trump spring clamps. But finger tabs and spring clamps trump screws if screw housings (often plastic in the aftermarket) get stripped. Bottom line is the specific execution in design and materials is key to the long term sealing reliability of the lid, especially if the lid is used to keep dirt away from the clean side of the filter. I have a GM that uses screws, a Toyota that uses spring clamps, and a lawnmower that uses a wing nut, and all three more easily maintain a reliable filter gasket seal than what we all have found with the stock Ford set up in this singular application. That isn't to say that the stock Ford airbox can't work without careful attentiveness. I maintained my stock airbox in place for 11 years (I had a deep supply of new filters left over from testing that I wanted to use up), until a friend needed an airbox immediately, but he didn't know it. My wounds for being the messenger was having to give up my as yet unbroken airbox, along with my remaining filters. Finally, I could justify installing the air box replacement I had been storing for over a decade, ever since its initial release.

6. Sometimes, it is possible to think outside the box, while still remaining inside. This point calls for a picture:



Notice the clean compression signature on the crown of this EPDM bulb seal.

This filter gasket seal represents a quadruple polygamist divorce:

A. This filter seal is no longer married to the responsibility of defining the filter's perimeter shape, like most flat panel filter gasket seals do.

B. This filter seal is no longer married to the resonsibibility of providing ANY stiffening structure whatsoever to the filter panel, like many filter gasket seals do.

C. This filter seal is no longer married to the task of binding the filter media together, while simultaneously keeping the fan folded filter pleats a set distance apart. It's like not having any kids to separate from fighting, or to include on the trip to Disneyland.

D. This filter seal is no longer married to the requirement of integrating with a machined production extrusion process. As such, the material selection palette expands to include other options, like EPDM instead of polyurethane, for example.

This type of filter sealing gasket is somewhat out of the box compared to the air filters that preceded it, and was made possible by a separate plastic structure that watches the kids, cooks dinner, and goes to work everyday holding the filter media together, while keeping it organized, and while providing a stable structure and clean environment for a better life. Happy Filter's Day!

 

I installed my AIS which was delivered today. Pretty straight forward with the install.

I didn't get to drive it much afterwards but it does seem a little quieter. I guess I can test it more tomorrow. I assume she is breathing better though. Maybe I will tell an improved mpg??

 

I didn't think there was any difference in noise from stock. MPG has been hard to tell because with the winter fuel, the 4 wheel drive and extra warmup time my MPG has dropped off a bit. I was able to hit 21-22psi of boost where before it was 18-19 max.

 

I hope not, I just received my AIS from riffraff today and have already installed it. Going out to the KFC tonight to give it a test run. I did start it up and let it run for a few minutes and it is way quieter than the airaid system I had, plus I got rid of at least a garbage bag full of plastic crap that I no longer need like the battery cover, big plastic battery tray and other junk. Cleaned it up rather nice in there now. Its still 70 degrees here so we can still work on our trucks

 

Truck has a CAI snorkel in OEM set up, the box is prone to leaking, so why not just install a round or cone filter inside the OEM box, get more airflow, no increase in noise and save a wad of cash?

Couldn't the 6637 or any cone filter be used for this purpose?

Is this the "blueprint or enclosing the 6637"?

 

Do you have the stock airbox in your 2002? Have you checked your air filter... lately? It never hurts to have another look, even if only to make sure the rectangular perimeter seal has not been compromised anywhere along the lid to lip junction.

And if you do decide to check, today, while it is fresh in your mind, then the physical improbability of succeeding in what you are suggesting in your post quoted above may become more apparent.

Notice that the stock rubber ducting attaches to the lid of the factory airbox only, not anywhere near the center of the box as would be needed for a round or conical air filter. The "clean" side of the panel filter is in the lid only, and that lid is too narrow to encompass the radius of a 6637... never mind the angle of the lid that diminishes to zero.

Even if you substituted a conical filter instead, their is not enough head room in the lid directly above the orifice to which you would attempt to attach the conical filter in order to fit... never mind the bottom half of the airbox being unusable.

There is a reason why at least 20 companies have spent money creating new plastic or metal parts to enclose and or protect cylindrical and conical filters in this application. The stock factory airbox doesn't lend itself to be repurposed to use any other type filter other than a flat panel, and even then, some flat panel filters do not fare very well around the lid seal.

Any 6637 "kit" or "blueprint" is going to involve introducing parts other than what can be found on the factory truck... even if those parts came from Home Depot, which they often do.

 

Excellent info, thanks much.

 

I'd rep Y2KW57 for the 2nd time today, but I need to spread it around first.

Where has that explanation been all my life? Definitely makes me happy that I went the AIS route, and mad that the PO used a stock box w/ K&N drop in for the first 189,000 miles.
I should print that post out for future reference, like explaining to my cheap father-in-law why he needs to get away from the stock box on his 2001.