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Reset filter restriction gage, took it out and tried it again, same thing occured. Took filter restriction gage out of new unit and put the old filter restriction gage in new unit. Light did'nt come on, checked filter restriction gage, it registered 65%.

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So the restriction gauges on the "X" have an electrical connection that feeds some in cab indicator

Larry

Edited by Larry M (08/01/03 08:06 PM)

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the stock airbox pulls at least 26 inches of water under full load, versus 15-17 with our intake. big difference...I wonder what the AIS pulls...I bet more.

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the stock airbox pulls at least 26 inches of water under full load, versus 15-17 with our intake. big difference...I wonder what the AIS pulls...I bet more.

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It depends on where you measure it, but the AIS Filterminder is set to trip at 25" H2O.

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I agree and I personally feel that people need to fully understand all these numbers and comparisons that are out there. A few observations I would like to share from my personal view and understanding in all this ....

While the second part of the statement HERE

"The factory filter gauge requires at least 26 inH20 to register, which is beyond what most Diesel Engine Manufacturers suggest for Filter Replacement. "

IMHO might be generally true I don't believe that the first part is accurate when included with the second part because the location where this 26inH20 was measured which I understand is HERE and will result in a much higher and hence biased readings with respect to the standard referred to in the quote above which I assume is probably at the outlet of the airbox, but is not stated so that is only an assumption on my part. This 26inH20 requires considerable interpretation to properly compare it to the general suggested filter replacement value cited and applied to our specific diesel engines. The standard for measuring acceptable vacuum restriction on the intake systems on the Ford Diesels is specified at the outlet cover of the airbox based on the Ford supplied specs for the AIS development and not somewhere downstream closer to the turbo where a fitting might be more convenient to hook up which is from my understanding where this cited 26inH20 above was measured at. Both the standard and the location for our engines I believe is best measured at the outlet cover of the airbox as set forth by a Senior Automotive Engineer who works for an actual filter system design company who has actually designed and put into the field a FORD factory approved air intake system for the 7.3L engine HERE and is as stated is 25inH20 max. However, this 25inH20 spec and the 26inH20 in the quote above I don't feel are directly comparable. The points in this Senior Engineer's post that I consider important are:

1. The 25inH20 max spec is at the outlet cover of the airbox, not somewhere downstream closer to the turbo that might be more convenient to measure at. As explained below these two readings can be vary different and I personally do not think they should be compared to each other directly without very careful and independent verification.

2. Regardless of what the initial restriction of any filter might be it seems the industry standard is to replace the filter when the restriction reaches 10inH20 above what the new filter reads. This is the way filters are designed by the industry as I understand it. There might well even be some cross over point in mileage where a less restrictive filter initially might load up quicker and even become more restrictive and require more frequent replacement than one that had a slightly higher initial restriction vacuum value, but loads up slower and in fact lasts longer. I have no data or engineering reference for this statement since it's a complete WAG on my part.


Both my test results on the filterminder F7TZ 9N622-A HERE along with the independent test results for a 94-97 filterminder (part # unknown) by Dale summarized HERE while having different values, does IMO give one at least some "back of the envelope" feeling for what the actual vacuum at the filtermider will be for various values on the filterminder itself. Mine was red at 27inH20 and Dale's was 36inH20 so for lack of any other data which I haven't seen posted lets average them and call it red at 32inH20, however I do note the very close values of my 27inH20 to the Ford's factory spec of 25inH20 and even averaging the two data points we have there is only like 7inH20 difference between the average of the two data points and Ford's specification. I realize the danger of comparing the localized vacuum values at the filterminder location against the vacuum at the outlet of the filter cover, but until I get my 0-30inH20 air filter gauge installed I can't map the correlation between the two just yet so there is my disclaimer in all this. Next, I had 22inH20 for 75% which I will assume was the 32inH20 for Dale's "yellow" reading ... the average is 27inH20 ... again while mine was lower than Dales, I find it interesting that each were amazingly consistent in the 4 inH20 between the 25% graduations on average. Now Dale didn't provide any other readings but my filterminder values showed a 4inH20 for every 25% below 75% the same as Dale's two data points for what I'm assuming is a 25% filterminder reading. Thus extrapolating Dales readings would give him 28inH20 at 50% vs. my 16inH20 (average 22inH20) and 24inH20 for Dale at 25% vs. my 12inH20 (average 18inH20) and a just move value (call this the 0% point) of 20inH20 for Dale and around 8inH20 for mine (average 14inH20). I found it very easy to get to the 25% value so this extrapolation to the 0% point could have a lot of error in it I used a water manometer for my tests(which requires no calibration) which I feel is quite accurate so I will post a side by side vacuum for both mine and the average of Dale's and my readings:

Mine/Average(all in inches H20)
0% - 8 / 14
25% - 12 / 18
50% - 16 / 22
75% - 22 / 27 (NOTE: around here is where we're reaching the 25inH20 Ford spec at the outlet of the cover)
100% - 27 / 29.5 (NOTE: only 2 to 4.5in H20 over the Ford spec which is close enough for me)


The statement above that:

"The factory filter gauge requires at least 26 inH20 to register" which is based as best as I can tell on the demonstration on Wexman's truck which is discussed below in measuring the vacuum at one location and applying/implying it is similar to another location, it needs to be understood that it might have little meaning as far as what either Ford or the apparent Industry considers acceptable restriction values which are at the outlet of the airbox cover.

I would also like to point out two very interesting statements in the above linked post of Dale's:

"However, I do find it interesting the the test gauge indicated a max of 28"H2O during one part of the test and the filter minder never moved."



and

"One last thought, although the minder was tested separately, the on vehicle testing was plumbed in the intake tract mid point at the breather element housing. I didn't want to take readings from the bend in the tube since you can get poor readings from there and I wanted to use the same port for the consistency of the readings.



My reading of these two statements is this confirms the premise that measuring the vacuum downstream of the outlet cover of the airbox is not indicative of what the vacuum is where Ford specifies the values for and might not even be a simple +/- adjustment and what Dale measured as 28inH20 downstream is very close to what was measured during Wexman's demonstration HERE which measured in excess of 26inH20 on a factory system at a point again much further downstream of the location that Ford specs the vacuum to be measured, but similar in location to where Dale I took his measurements.

Just my observations and comments and none of this is to imply that lower restrictive filters are not better regardless of measurement points, but at least in my view how much better is needed is something I will leave to more knowledgeable people to quantify and defend ... I feel there might be some restriction value of any aftermarket air intake system that could reach a point of diminishing returns for a certain engine configuration, but I have no idea how to quantify that.

All this is sort of like what an "ole and sage" NPGS Professor of Statistics and Probability aways said ... "When one states a mean and standard deviation/variance w/o putting a confidence level on those, one should always be suspect that there is more to the story" ... which basically means one needs to understand the whole issue when numbers/comparisons are cited and not simply focus on the numbers themselves.

Larry

Edited by Larry M (08/02/03 06:37 PM)

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With those parameters fixed, the size of the filter was pretty much set. It starts out with a 10" H2O restriction and sets off the Filterminder at 25". That's what it is, that's what it does. Nothing more, nothing less.

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1b. There is another part of your first question that I'd like to touch on here. You had asked if the indicator were graduated in 25, 50, and 75% positions, would that mean that each would correspond to their respective percentage of the 25"H2O total? I think I got that right.. To answer this, I need to point out that we need to figure in a very important value into this equation. That value would be the "Initial Restriction". The initial restriction would be the restriction value of the system with a clean element at the rated flow. The OEM's adhere to a SAE J726 spec for dust loading of filter elements. That spec says that there should be a 10"H2O rise in restriction over the life of the filter. So the initial restriction will be the terminal restriction (25"H2O) minus the 10"H2O rise, falling somewhere in the 15"H2O area for a initial restriction value. So IF this were a graduated indicator that we could assign values to, the values would be distributed throughout the 15-25"H2O range when figuring in the initial restriction of the system.

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OOOOPS.

Larry, you are right. Sorry for the mis-info everyone. Here is the quote:

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1b. There is another part of your first question that I'd like to touch on here. You had asked if the indicator were graduated in 25, 50, and 75% positions, would that mean that each would correspond to their respective percentage of the 25"H2O total? I think I got that right.. To answer this, I need to point out that we need to figure in a very important value into this equation. That value would be the "Initial Restriction". The initial restriction would be the restriction value of the system with a clean element at the rated flow. The OEM's adhere to a SAE J726 spec for dust loading of filter elements. That spec says that there should be a 10"H2O rise in restriction over the life of the filter. So the initial restriction will be the terminal restriction (25"H2O) minus the 10"H2O rise, falling somewhere in the 15"H2O area for a initial restriction value. So IF this were a graduated indicator that we could assign values to, the values would be distributed throughout the 15-25"H2O range when figuring in the initial restriction of the system.

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Jeff, no problem I've mis quoted and missed the point more times that I care to admit and all that's important that we all end up at the same point or at least understand that point if different in our view in the end. I also understand if you use a real vacuum gauge you can take this 10inH20 rise within a reasonable distance from the outlet of the airbox cover which I interpret to be in the area of where the factory designers located the filterminder. I plan to install a tap next to the filterminder and one at the outlet of the airbox and go from there. Just wish I could get my gauges sooner than the 4 to 5 weeks I was quoted. I already have all the DOT vacuum lines, DOT fittings and stuff for the install ... just waiting on the gauges from Ashcroft.

Larry

Larry