I'd send you a pm/email but apparently have to have 15/20 posts to do so. Hate to just pad...So.........If anyone's interested, I've got a one month old 6637 with 4"x4" pipe and clamp that's been run in clean environment (no dust) up for grabs.......PM me.
Now that wasn't thinking very well on my part, if you've only got 10 posts you can't send a pm either... sorry.I'd send you a pm/email but apparently have to have 15/20 posts to do so. Hate to just pad...
Not sure if I can receive PMs or not, but you can try to send me one if you want. I'm interested in more detail.
I agree with your statement and when I still had my F350 I spent several years towing my 5er with different versions of a zoodad and measuring the inches H20 "suction" that my turbo applied to my AIS and I compared those measurements to similar measurements made on a 6637 by "Tenn" who posts on FTE. In the picture below on the left side of the "Magnehelic" gauge you can just make out a brass fitting with a clear hose attached which runs to the fitting on the AIS box shown in the second picture. I used the gauge on the left to measure "crankcase pressure" while evaluating different CCV mods but that's another story....As long as you zoodad your core support you'll have plenty of flow through the AIS. Without the zoodad there's a restriction, but it's not the filter, it's the snorkle butting up against the core support. The snorkle on the AIS is slightly longer than the stock airbox and virtually seals itself against the back of the core support...
So what this is saying is that the filter has way more flow capacity than the size of the tube that delivers the air to the turbo inlet? The only thing really causing the suction measured in the tube neck is venturi effect thru the narrower tube?Tenn used an identical "Magnehelic" gauge and he measured the inches H20 "suction" applied to a 6637 at two different locations. He did a few tests with his "Magnehelic" gauge hooked to a fitting in the cap at the "dead end" of the 6637 as is shown below but it turns out that for a clean 6637 hardly any suction makes it all the way out to the very end because even under load the airflow demanded by the turbo gets satisfied by the airflow through the part of the element's surface that's nearer to the neck of the filter.
As the inner portion of a 6637 loads with dirt the suction gets forced farther out towards the dead end portion of the filter so that air is forced to flow through the part of the element's surface that's closer to the end cap as is required to satisfy the airflow demanded by the turbo. Tenn did an experiment in his driveway which kind of simulated this by placing a rag around the inner portion of his clean filter and revving the engine to measure the increased suction at the end cap. These measurements indicate to me that due to its "dead end" cylindrical design a 6637 doesn't fully utilize all of its surface area at any one time!
So if both of your filter types are overkill for the tube diameter, it would make sense that you would both indicate the same max suction (before he upgraded his turbo). The max suction for both at that point is really based upon the tube size and volume of air thru it?During the rest of his testing Tenn measured the inches H20 "suction" applied to the neck end of the 6637 as is shown below because this is where it must be measured in order to see the suction that corresponds to the airflow through the total surface area of the 6637 element.
If anyone's interested in the raw data and the analyses of the data I can find some links to it or post a summary here but the bottom line is that we both had DP chips and while towing under similar conditions of load as defined by RPM and BP Tenn and I both saw about the same values of inches H20 "suction" being applied to the 6637 and to the AIS and the maximum suction seen was 12" H2O. Tenn has since upgraded his injectors and turbo and he can now easily pin his Magnehelic gauge at well past its full scale reading of 15" H2O!
There is an ASTM or ISO standard for just about everything. The information is just difficult to find unless you work in an engineering office.thanks for the great detail of the investigation work ErnestEugene. Both the ISO-5011 info and your personal experience. Interesting testing, I didn't know there was an ISO standard.