TheDieselStop.Com Forums: Air Filter/AirBox Study at Banks: The Results Are In! Part 1

Preliminary Flow Bench Test Report on Selected Air Filters and Related Air Box Housings for the 1999-2002 Ford Powerstroke Diesel in F-250/350/450/550 Superduty Truck And Excursion Applications

Part 1.

THE SWEET SPOT!

In reply to:
If the sweet spot is 22 to 1, then, to put more fuel in at an air/fuel ratio of 22 to 1, YOU NEED MORE AIR. Otherwise, it just goes… SMOKE!

Gale Banks - April 8, 2002

I'll tell ya what smoke is. Smoke is what I'd be if I didn't hurry up and get some of this stuff posted.

Smoke is what has been billowing in my brain … trying to make sense of what I learned on the flowbench about these air filters and airboxes a month ago. Smoke is what has been burning my eyes, with all of the textbook reading during the 31 days since on gas properties, fluids, thermodynamics, air density, and oh yes, air filtration.

Smoke is what Gale did to more than a half day of painstakingly gathered data when we accidentally discovered a possible variable in the process that could potentially render non-repeatable readings. “Get rid of all the old data,” Gale fumed. He continued, (in my own paraphrasing) “It’s no good whatsoever if there is a possibility of errors.” But we worked so long and hard on it, I protested, desiring to keep at least a copy of the old readings, just for reference or comparison. “No, throw them away,” Gail fired back. “They serve no purpose if they are inaccurate, and could confuse us down the road.” Troy Larson, Manager of the Instrumentation and Test Group, smoked all the bad data out of the computer. As we began a clean sheet repeat of ALL of the previous testing, with the variable fixed, Gale related a story out of his engineering past when confusion with old data almost happened. He caught it in time, but not without a bit of frustration. Today, Gale literally tears up any suspect data, and starts over again.

When it comes to considering air filters, I needed to start over again, too. Smoke is what remains of my previous assumptions about the flow capacity of certain air filter’s and their boxes, assumptions now burnt to ashes as a result of our preliminary flowbench tests. Smoke is what some after market air filter products could be going up in soon, if forthcoming instrumented on-vehicle and dyno testing bears out what was discovered recently on the flow bench. Now that will be some smoke, considering the prices fetched for those aftermarket products. I wouldn’t want to be near the fire.

I’d rather be in the sweet spot.

The sweet spot had to have been where I was standing on April 5 and April 8: In the middle the racing shop of Gale Banks Engineering, with Gale Banks to the left, Troy Larson to the right, a calibrated flow bench in front of us, a whole stack of PSD air filters and air boxes behind us, and a common desire to test, not guess, within us. Ringing in our ears in the foreground was the shopvac-on-steroids howl of the stereo suction blowers under the Superflow bench we were working with, and in the background through the walls was the blood curdling scream of my poor truck on the chassis dynamometer outside the building, turning 3,200 death defying RPMs. While the dyno testing to establish a baseline power level with my particular Powerpack was a separate operation from this preliminary flow bench evaluation of air filters, both events together embodied Gale Banks following through with each promise, never flinching from any challenge presented, and overall being a gracious host. Every PSD owner is a beneficiary of this air box/filter evaluation, since the information may prove useful in making air intake performance and/or maintenance decisions. Gale Banks, John Espino, Troy Larson, and the rest of the company deserve public thanks for opening their facilities and making very intelligent staff and excellent equipment available, despite enormously pressing priorities in many other directions. To be able to participate in this process, and to share it with fellow members of Ford.Diesel.com… that is indeed the sweet spot.

HAVE AT IT!

In reply to:
"Yeah, I’m real curious… Let’s de-rig this and have at it."

Gale Banks – April 5, 2002

Preliminaries and introductions are what we are taught to write in school, but as time-crunched adults, we often skip over the “story” to get right to the “hard data,” and only skim that data briefly enough to get to the “bottom line.” The eye of human nature quickly skims the lines to scan for the highest and lowest numbers, note the associated products, and Done: Conclusion Drawn.

In this case, which air filter is best? I would rather draw the discovery process out more. (Obviously, by the time it has taken me to post this, which is only 25% of the material prepared) Yet, in this write-up, if I venture much further now in describing the test parameters, equipment identification, ambient conditions, range limitations, and additional background information on the products gathered as recently as this morning … it might get skipped over anyway. So I’ll post all the laboriously prepared details about how the flowbench works, who makes it, what it uses to measure, how it relates with the software, etc. later. To quickly satiate the skimmers and scrollers by putting up this test table first, and highlighting the product and the CFM, it is hoped that the appetite will be wetted to wonder why the results are as they are, as my appetite was wetted while discovering them. Although this data was gathered with care, an impartial machine, and without any bias on my part, it is still not yet worthy of drawing any quick conclusion from.

A professional class flowbench of the caliber found at Gale Banks Engineering is a useful tool for first order approximation. It beats looking at the air box and filter and just guessing. It beats paying for a product, installing it, and justifying the effort and expense with the “feeling” of the seat of the pants. But a flowbench is not a truck laboring on a 7 percent grade sucking wind while stuck behind a dusty gravel dump. It will not determine how quickly it will take for a filter to load up with dirt to a greater than recommended restriction. And it will not, on it’s own, determine any net power gain to be derived from using a particular filter and airbox combination without the assistance of other data , and without verification by dyno testing. While I have already done some limited dyno testing with selected air filters in a stock air box prior to establishing a baseline performance level on the Banks dyno, the level of instrumentation was meager compared to how Banks engineers dyno products under evaluation or development. Unless and until the air boxes and filters in this study get tested while mounted in the truck on the dyno under those highly instrumented and controlled conditions, the results of the flowbench data will remain limited to how well mostly clean filters flow while sitting stationary inside a building.

On the other hand, all things being thus made equal, some filters and air boxes flowed more air while sitting stationary in that building than others. It doesn’t take much of a leap of faith to believe that the higher flowing filters might stand a better chance to flow more air in other conditions as well.

While we only sought to evaluate how air filters and their commensurate boxes flow air, of equal if not much greater importance is how they filter air. This aspect of the equation remains completely unconsidered in the work below. There are industry standard tests, such as the SAE J726 Contaminant Capacity/Efficiency Test, that identify the performance level of automotive air filters in the form of Dirt Holding Capacity in Grams at a specified Restriction in CFM for a determined Efficiency in Percent. Strict methodologies respecting particulate size, rate of introduction into the flow stream, duration of feed, weighing of the clean and loaded filter, and other aspects of this testing render it out of the scope of capabilities available at Banks Engineering. The filter manufacturer’s themselves often use independent labs to perform this and other standardized filter evaluations, such as the AC and Visteon water soak tests. It is likely that data provided by the filter manufacturer’s from the results of these independent tests will be all that is available to compare, unless such a lab is hired by Banks, myself, or perhaps you… to verify those claims.

Finally, even controlled dyno testing, complete with twin giant squirrel cage blowers facing the front of the truck to simulate 60 mph headwinds, should be supplemented by instrumented on-vehicle testing on the road. Banks is capable of doing this, and has done so before. While controlled steady state conditions are important for fairly comparing product-to-product performance data, real world conditions are hardly controlled. How does one assess the effects of crosswinds stronger than headwinds? 18 wheeler drafts? Weird turbulence? No wind at all? Searing desert heat on a hot, treeless, asphalt stretch to infinity? Light snow flurries, where the wispy flakes of crystals float lighter than the wind, easily sucked in by the “ram-air,” flying past any drainage provision in the air box only to then condense on the filter and freeze dam the flow? Engineering for the worst cases of real life is a heavy burden, even if only an imaginary one. Flowbenches and dyno’s are the indices of the ideal. How do we bridge to the realm of the real?

Therefore continue wading into this report with this bifold caution: that full absorption of the background data that will eventually follow this table, plus vigilant maintenance of the perspective that the data contained herein is inconclusive to date, are both critical to understanding the results within the contextual framework of the testing intent.

Thus armed, let’s de-rig this prose and have at it:

TEST RESULT TABLE

Air Box: Western Diesel Turbo Ram Air
Box Characteristics: Complete air box replacement system. Baffled inlet air scoop occupies top frontal grille opening area, requires lowering A/C condenser and reorienting battery longitudinally, tray provided.
Note: As this is a non standard aftermarket induction system, full dimensions of airbox, inlet, filter surface area, the crossectional area of various planes of flow through the ducting and at the filter port shall be added to this description or to an addendum to this report as time and opportunity allow.
Box Applicability: Manufacturer states shall fit all SuperDuty F Series and Excursions 1999-2002
Note: Entire air box fully assembled with seams secured with duct tape for bench testing purposes
Box Manufacturer: Western Diesel, contracted suppliers unknown
Air Filter: Western Diesel, proprietary
Filter Characteristics: Conical shaped open cell foam air filter
Filter Manufacturer: Western Diesel, contracted suppliers unknown
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Step Setting for Optimal Range Accuracy in Flow Measurement: 9
Average of 30 readings after steady state established: 628.8 CFM

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third known OEM revision, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: New Motorcraft 1710 FCSD Parts & Service Version 1C3Z-9601-AA
Filter Characteristics: Black polyurethane gasket surround, 76 folded pleats, large open diamond thin web expanded metal of .035” major diameter, two parallel glue bead stiffening strips across pleats
Filter Manufacturer: (Still investigating)
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 761.4 CFM

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third known OEM revision, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: Used Motorcraft 1710 Original Equipment Version 1C3U-9601-AA
Filter Characteristics: Orange polyurethane gasket surround, 56 folded pleats, small open diamond thick web expanded metal of .045” major diameter, cross-flow alternating gap emboss pattern on phenolic media
Filter Manufacturer: Dana Corporation, Wix Filter Division
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 776.0 CFM

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third OEM revision for application, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: New Wix #46648
Filter Characteristics: Orange polyurethane gasket, expanded metal screen, embossed pleats, equivalent in features to the final version of the OE Ford 1680, but not necessarily to variants of Motorcraft FA-1680
Filter Manufacturer: Dana Corporation, Wix Filters
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 780.4 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New Motorcraft 1710 FCSD Parts & Service Version 1C3Z-9601-AA
Filter Characteristics: Black polyurethane gasket surround, 76 folded pleats, large open diamond thin web expanded metal of .035” major diameter, two parallel glue bead stiffening strips across pleat crown face
Filter Manufacturer: (Still investigating)
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 791.3 CFM

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third OEM revision for application, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: New Motorcraft FA-1680
Filter Characteristics: Orange polyurethane gasket, other data to be redetermined. Note that the number of variant versions of the Motorcraft 1680 and/or the equivalent Ford OE 1680 has not yet been established
Filter Manufacturer: Dana Corporation, Wix Filters Mfr. subject to re-verification
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 791.4 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New Motorcraft 1710 Original Equipment Version 1C3U-9601-AA
Filter Characteristics: Orange polyurethane gasket surround, 56 folded pleats, small open diamond thick web expanded metal of .045” major diameter, cross-flow alternating gap emboss pattern on phenolic media
Filter Manufacturer: Dana Corporation, Wix Filter Division
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 803.2 CFM

Note: The combination immediately above was re-tested again as an exception comparator for OE snorkel flow effects, detailed later in this study, but not listed in this particular report. As configured above, the second average CFM was 806.1.

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third OEM revision for application, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: Used Gale Banks Engineering Ram-Air ‘99.5 – ‘01 Part Number 41511
Filter Characteristics: Oiled Cotton Gauze captured in a fine AL wire mesh screen on both sides of a pleated panel filter designed as a drop-in OE replacement for the XC3U-9600-AA factory air box. Similar to K&N panel replacement filter, also tested in this study. Gasket compounding noticeably differs in material density and durometer (hardness) from the K&N equivalent. A highly subjective characterization of the difference would be that this filter (S&B) gasket is “softer” and “stickier” to the touch. Gasket sealing profile, peripheral shape, and attachment to the filter media is also notably different from K&N. Partly due to the position of the media to the gasket, and partly due to the shallower crown to valley depth of the pleat, unlike the K&N, this filter remains remarkably unaffected by the new stabilizer post found in the lid of the updated Ford 1C3U-9600-AA airbox. Fibers in the filter media are the same as or similar to the natural cotton gauze in K&N, and are specifically and verifiably not synthetic fibers.
Filter Pleat Height: .947” clean side crown exterior to dirty side crown exterior, using micrometer.
Filter Pleat Count: 34 crowns, counted from dirty side. Additional 2 crowns at either end cast in gasket.
Note: Gale Banks Engineering may contract with various filter manufacturers for supplying Ram-Air branded filters that meet Bank’s specifications. As of this writing, Banks Ram-Air filters offered for the PSD application are being supplied by K&N, even though the filter in this particular configuration was not.
Filter Manufacturer: S & B Pow-R-Plus Filters, Model 66-2123
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 807.7 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: Used Motorcraft 1710 Original Equipment Version 1C3U-9601-AA
Filter Characteristics: Orange polyurethane gasket surround, 56 folded pleats, small open diamond thick web expanded metal of .045” major diameter, cross-flow alternating gap emboss pattern on phenolic media
Filter Manufacturer: Dana Corporation, Wix Filter Division
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 810.3 CFM

Air Box: 2001.5 – 2002 Ford Motor Company Stock Air Box 1C3U-9600-AA
Box Characteristics: Third OEM revision for application, with new stabilizer post in lid, closure guides in base, revised (thicker) lid tab retainers, and deeper filter baffle designed for a 3” thick paper filter
Box Applicability: Original Equipment for build dates of 11/25/2000 and newer; retrofittable to all Super Duty F Series, including early 1999, and early Excursions, with completion of TSB Article 01-9-5
Box Manufacturer: Visteon Corporation
Air Filter: New K&N Engineering Filtercharger NA-33-2138
Filter Characteristics: Oiled Cotton Gauze captured in a fine wire mesh screen on both sides of a pleated panel filter designed as a drop in OE replacement for the XC3U-9600-AA factory air box. Similar to S&B panel replacement filter, also tested in this study. Fibers in the filter media of the K&N are multi-layered, reportedly 5 layers of 100% surgical cotton. Gasket compounding noticeably differs in material density and durometer (hardness) from the S&B equivalent. A highly subjective characterization of the difference would be that this filter (K&N) gasket is “harder” and “slicker” to the touch. Gasket sealing profile, peripheral shape, and attachment to the filter media is also notably different from the S&B. Gasket surround has two locating/orientation tabs that align with outboard end of air box. Partly due to the position of the media to the gasket, and partly due to the higher crown to valley depth of the pleat, unlike the S&B, this filter is easily damaged by the new stabilizer post found in the lid of the updated Ford 1C3U-9600-AA airbox. A “virgin” K&N 33-2138 filter was removed from the package and installed in the latest 1C3U air box for testing purposes, and within this test 3 pleat crowns on the clean side were found to be deformed, with the wire mesh punctured. This problem does not exist in the earlier XC3U box for which this filter was designed, and can be overcome in the later box by reducing the length of the interior lid post by 5 mm. K&N has announced a forthcoming redesign of the filter for simple drop-in applications to the 1C3U box.
Filter Pleat Height: 1.245” clean side crown exterior to dirty side crown exterior, using micrometer.
Filter Pleat Count: 36 crowns, counted from dirty side. Additional 2 crowns at either end cast in gasket.
Filter Manufacturer: K&N Engineering, Inc.
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 814.7 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New FRAM 8925
Filter Characteristics: Pleated paper replacement filter. Paper is whiter in color, an indication of a different type of treatment process than the Wix or Motorcraft pleated paper filters evaluated in this study. A more detailed description is in development.
Filter Pleat Height: Approximately 2 inches. Very similar in size to any version of the 1680
Filter Pleat Count: To be determined
Filter Manufacturer: Honeywell Consumer Products Group (Formerly AlliedSignal)
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 823.6 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New Motorcraft FA-1680
Filter Characteristics: Orange polyurethane gasket, other data to be redetermined. Note that the number of variant versions of the Motorcraft 1680 and/or the equivalent Ford OE 1680 has not yet been established
Filter Manufacturer: Dana Corporation, Wix Filters, subject to re-verification
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 823.9.CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New Wix #46648
Filter Characteristics: Orange polyurethane gasket, expanded metal screen, embossed pleats, equivalent in features to the final version of the OE Ford 1680, but not necessarily to variants of Motorcraft FA-1680
Filter Manufacturer: Dana Corporation, Wix Filters
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 828.1 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New K&N Engineering Filtercharger NA-33-2138
Filter Characteristics: Oiled Cotton Gauze captured in a fine wire mesh screen on both sides of a pleated panel filter designed as a drop in OE replacement for the XC3U-9600-AA factory air box. Similar to S&B panel replacement filter, also tested in this study. Fibers in the filter media of the K&N are multi-layered, reportedly 5 layers of 100% surgical cotton. Gasket compounding noticeably differs in material density and durometer (hardness) from the S&B equivalent. A highly subjective characterization of the difference would be that this filter (K&N) gasket is “harder” and “slicker” to the touch. Gasket sealing profile, peripheral shape, and attachment to the filter media is also notably different from the S&B. Gasket surround has two locating/orientation tabs that align with outboard end of air box. Partly due to the position of the media to the gasket, and partly due to the higher crown to valley depth of the pleat, unlike the S&B, this filter is easily damaged by the new stabilizer post found in the lid of the updated Ford 1C3U-9600-AA airbox. A “virgin” K&N 33-2138 filter was removed from the package and installed in the latest 1C3U air box for testing purposes, and within this test 3 pleat crowns on the clean side were found to be deformed, with the wire mesh punctured. This problem does not exist in the earlier XC3U box for which this filter was designed, and can be overcome in the later box by reducing the length of the interior lid post by 5 mm. K&N has announced a forthcoming redesign of the filter for simple drop-in applications to the 1C3U box.
Filter Pleat Height: 1.245” clean side crown exterior to dirty side crown exterior, using micrometer.
Filter Pleat Count: 36 crowns, counted from dirty side. Additional 2 crowns at either end cast in gasket.
Filter Manufacturer: K&N Engineering, Inc
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 851.9 CFM

Note: The combination immediately above was repeated, and is listed later, with higher results, at 854.8.

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: Used Gale Banks Engineering Ram-Air ‘99.5 – ‘01 Part Number 41511
Filter Characteristics: Oiled Cotton Gauze captured in a fine AL wire mesh screen on both sides of a pleated panel filter designed as a drop-in OE replacement for the XC3U-9600-AA factory air box. Similar to K&N panel replacement filter, also tested in this study. Gasket compounding noticeably differs in material density and durometer (hardness) from the K&N equivalent. A highly subjective characterization of the difference would be that this filter (S&B) gasket is “softer” and “stickier” to the touch. Gasket sealing profile, peripheral shape, and attachment to the filter media is also notably different from K&N. Partly due to the position of the media to the gasket, and partly due to the shallower crown to valley depth of the pleat, unlike the K&N, this filter remains remarkably unaffected by the new stabilizer post found in the lid of the updated Ford 1C3U-9600-AA airbox. Fibers in the filter media are the same as or similar to the natural cotton gauze in K&N, and are specifically and verifiably not synthetic fibers.
Filter Pleat Height: .947” clean side crown exterior to dirty side crown exterior, using micrometer.
Filter Pleat Count: 34 crowns, counted from dirty side. Additional 2 crowns at either end cast in gasket.
Note: Gale Banks Engineering may contract with various filter manufacturers for supplying Ram-Air branded filters that meet Bank’s specifications. As of this writing, Banks Ram-Air filters offered for the PSD application are being supplied by K&N, even though the filter in this particular configuration was not.
Filter Manufacturer: S & B Pow-R-Plus Filters, Model 66-2123
Combination of this Air Box and Air Filter flowbench test results:
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 852.3 CFM

Air Box: 1999.5 – 2001 Ford Motor Company Stock Air Box XC3U-9600-AA
Box Characteristics: Second OEM revision for application, designed to eliminate several problems found in original 1999 fender well inlet system, and to coordinate air induction with battery cooling (per the mfr.)
Box Applicability: Original Equipment for build dates of 12/07/1998 and newer; formerly retrofittable to all previous Super Duty F Series from 1/98 to 12/7/98 equipped with original F81A-9600-AA box per TSB Article 98-16-11, superceded by 99-6-4. Box (XC3U) is now obsolete, as is the box (F81A) it replaced.
Box Manufacturer: Visteon Corporation
Air Filter: New K&N Engineering Filtercharger NA-33-2138
Filter Characteristics: Oiled Cotton Gauze captured in a fine wire mesh screen on both sides of a pleated panel filter designed as a drop in OE replacement for the XC3U-9600-AA factory air box. Similar to S&B panel replacement filter, also tested in this study. Fibers in the filter media of the K&N are multi-layered, reportedly 5 layers of 100% surgical cotton. Gasket compounding noticeably differs in material density and durometer (hardness) from the S&B equivalent. A highly subjective characterization of the difference would be that this filter (K&N) gasket is “harder” and “slicker” to the touch. Gasket sealing profile, peripheral shape, and attachment to the filter media is also notably different from the S&B. Gasket surround has two locating/orientation tabs that align with outboard end of air box. Partly due to the position of the media to the gasket, and partly due to the higher crown to valley depth of the pleat, unlike the S&B, this filter is easily damaged by the new stabilizer post found in the lid of the updated Ford 1C3U-9600-AA airbox. A “virgin” K&N 33-2138 filter was removed from the package and installed in the latest 1C3U air box for testing purposes, and within this test 3 pleat crowns on the clean side were found to be deformed, with the wire mesh punctured. This problem does not exist in the earlier XC3U box for which this filter was designed, and can be overcome in the later box by reducing the length of the interior lid post by 5 mm. K&N has announced a forthcoming redesign of the filter for simple drop-in applications to the 1C3U box.
Filter Pleat Height: 1.245” clean side crown exterior to dirty side crown exterior, using micrometer.
Filter Pleat Count: 36 crowns, counted from dirty side. Additional 2 crowns at either end cast in gasket.
Filter Manufacturer: K&N Engineering, Inc.
Test Pressure Setting: 25” water column restriction (static flow delta P)
Calibrated Orifice Setting for Optimal Range Accuracy in Flow Measurement: 10
Average of 30 readings after steady state established: 854.8 CFM

Note: The test immediately above is a repeat of the test before the test preceding it on this list.

A second run was see run to see if the best combination of OEM air box and new replacement panel filter could repeat itself. It obviously did. The test result immediately above happened to be the fourth test of the late afternoon on our “clean sheet repeat”, after we threw away all the work done earlier in the day because of the variable in the intake duct lashed to the machine. A more complete description of this variable shall be an additional installation to this report. In the meantime, at 854.8 CFM, this result loomed as the best recording of the day, and actually preceded the result for the same combination we repeated of later, at 851.9 CFM, as listed earlier.

OUT OF BREATH

Aren’t you? Believe it or not, there are 19 more unique air/filter combinations left to report in another installment! This makes a great pausing point, though, for several reasons. First, this fairly summarizes all of the evaluation of the stock air box with replacement filters. The other 19 tests involve air box deviations that may use parts of, but not all of the factory air induction pieces, placement, or hardware. The Western Diesel was an exception to the other aftermarket products for several reasons, including the fact that it was the only system that involved an entire replacement and re-arrangement of the existing air induction location, and even involved re-arrangement of other parts of the truck. And, the Western Diesel was already assembled and undergoing evaluation by Banks engineers prior to my arrival, so it was slated for the first day. Which brings us to another reason we can stop here. This ends the testing done Friday, April 5, a day that lingered on until 7:30 or 8:00 PM that night.

When I arrived back on Monday morning, April 8, I learned that Gale had come in to work on both Saturday and Sunday, to catch up on other projects that he might have doing Friday, if he wasn’t so busy holding up airboxes at the flowbench. Say what you want about Gale, but just make sure you include “relentless energy” and “dedicated to his business” when you're through.

Sometimes I try to explain an idea to Gale... usually it would turn out to be something that he had already done before I was born. Yet, in person, he patiently listened to me make an innocent fool of myself. And would you believe, I'm still not in agreement about the various tradeoffs with air filters yet? Some people need to be hit over the head with a brick. Hopefully, you learn easier than I do. You can see for yourself the results of Gale's thinking on the tests above. And you can see where my factory filter suggestions are in relationship to that. The list is ordered from the least flowing combination at the beginning, to the highest flowing combination at the end. The top three highest flowing systems, listed last, are derivatives of Gale Banks Power systems installations.

My suggestions for factory filters are somewhere nearer to the bottom of the flow priority barrel. You'll find them nearer to the top of the list. At least their not at the very, very top. The Western Diesel Turbo Ram Air snagged that distinguishment from me.

And to think, a little ol' cheap Fram outflowed us both.

You can also see that the newest factory airbox(1C3U) consistently flowed 35 to 50 CFM LESS than the intermediate factory airbox (XC3U) it replaced. It seemed clearly due to the lowering of the filter baffle by Ford and Wix engineers, done for the deeper (3") filter update. And what about that deeper pleat filter? Wouldn't you think that more exposed surface area, I mean a good 30% more... 3 inches per pleat versus 2 inches per pleat... would allow more opportunity for air to permeate a filtering membrane so sized? A one inch difference per pleat, that is like adding a whole 'nuther panel filter to the original one. Why is it then, that the Black 1710 consistently flows 20 CFM LESS than the variants of the 1680 filter it replaced?

And what about the Orange 1710. Not discontinued after all, only reserved for OE production. Open any new 2002 on a lot today, if you can still find one, crack open the air box. Orange.

Less pleats.
More flow.
Send me your recipies,
For delicious crow.

Gale Banks has a theory about why neither of the 1710's are flowing as high as the 1680... but rather than discuss it in this installment, I'd like to hear YOUR un-influenced comments as to why this occurs. Be sure and review the actual data first, don't take this cheap summary of mine as gospel... compare the data, goodness knows that is why I've spent UNTOLD HOURZZZZZ typing it all in. I probably have a good 5 or 6 hours in just editing the darn UBB code! Print it out, put it in a spread sheet! That is why the identifiying data is color coded.

Blue = Air Box
Red = Air Filter
Green = Air Flow

Monday’s tests revealed even higher flowing systems that replaced and/or deleted portions of the stock air box, and used conical air filters, often unsealed to the engine compartment. Look for that report in a few weeks, as I flesh out the data above over the next week. In the meantime, here is what Gale Banks has to say about some of those higher flowing air induction systems:

In reply to:
No device that adds to airflow should add to temperature at the same time. What you’re looking for is airflow AND lower temperature.

Gale Banks – April 8, 2002

(Said in response to my implying that a little derelict underhood heat would be eclipsed by the lower pressure drop of a more, conical open filter)

What I believe he is talking about here is AIR DENSITY, and, after being challenged several times by Troy Larson to bust out Boyle’s law, I’ve scribbled a few notes on that too, to be integrated with one of the installments of this article-in-progress.

Now I need to go out and get some air, and keep it cool.

Jason,

Part of the report that is "missing in action", and is to be included with later installments the more racy aftermarket filter housings, are about 3 pages of alternate calculations on CFM requirements... at specific RPMS, pressure differentials, and temperature differentials. Rather than post those yet, I wanted to wait until several calls into International came back. I have, after several weeks of trying not to make a heel out of myself, finally tracked down one or two of the engineers who actually worked on that aspect of the 7.3, and would really like their considerations first before posting any definitive statement on airflow requirements.

And I say guess work because of the assumed volumetric efficiency factor involved. And then people have different turbos, with differing A/R, different chips with differing ways to hold back the wastegate, etc. And then there are temperatures, barometric pressures, it can get as involved as you want I suppose.

In trying to estimate the peak air demand, in cfm, of a 444 cid turbocharged diesel, it was my hope that I can come up with a reasonably believable estimation without verified temperature data. The only reason for this is because most people only have BOOST guages installed, and don't have access to the thermistor information that the PCM receives from the IAT and the MAT, nor do most people add their own thermocouples like Banks does to all of his test mule trucks.

I am willing to make reasonable assumptions on temperature and barometric pressure, but how important are those numbers in a mere thumbnail equation for the purpose at hand, which is to determine if a particular air filter/air box combination is capable of flowing the engines peak demand air while at maximum allowable restriction... which is say 25 inches of water, an accepted benchmark amoung heavy duty turbodiesel engine manufactures.

A popular method for estimating CFM requirements for a natrually aspirated engine is as follows:

CFM = [CID x RPM x VE] / [2 x 1728]

Where:

"x" is my symbol for multiplicaton
"/" is my symbol for division, or a ratio

And where, although you may already know the acronyms, constants, and symbols, yet you may want to see if I am using them appropriately:

CFM = Cubic Feet Per Minute
CID = Cubic Inch Discplacement
RPM = Revolutions Per Minute
VE = Volumetric Efficiency
2 = 2 strokes per crank revolution (4 stroke engine)
1728 = conversion of cubic inches to cubic feet.

The question then becomes identifying a value for VE. Most people in this line of endeavor seem to agree that .85 is a reasonable value to use for a naturally aspirated (NA) engine. The NA VE numbers I have run across ranged from a low of .80 to a high of .90. Most were .85 . However, VE numbers for turbocharged (TC) engines, and turbocharged intercooled (TCI) engines, varied widely! I read of TC VE numbers from 1.2 to 1.8, and TCI VE numbers from 1.4 to 2.3. The average TCI VE of all of the material thus far reviewed seems to be 1.7. Intercooling makes a palpable difference in final efficiencies because of the great reduction in temperature.

The temperature drop across my Banks intercooler is 150 degrees, inlet to outlet... but like I said, I just don't want to think about temperature right now. I'm hard headed. I refuse to know. I'll plod along looking for a good VE...

I should be more clear at this point. When I said "reading" and "reviewing" and "materials" two paragraphs above, I am refering to papers and texts. I am not refering to readings from instrumentation, or calculations made from instrumented readings.

Anyway, besides temperature, notice there is no provision in the formula to account for boost pressure in a TC or TCI engine. Then, notice that because a boosted engine ENHANCES efficiency greater than the engine, as a pump, could do on its own, how do I pick an appropriate TC or TCI VE?

In the absence of a consistant guide on TC/TCI an due to the varibles alluded to earlier, might as well start searching for CFM requirements with what we have with that standard formula, and correct with the delta P and T ratios later.

Reviewing the definition of VE... a positive displacement pump property. A percentage of clearance volume defined as a proportion related to the swept volume of the pistons. Even while the importance of air density, the mass of air, or finding a density ratio determined by a ratio of absolute inlet and outlet temperatures multiplied by the ratio of absolute inlet and outlet pressures still loomed in my head, I wondered... if the flowbench machine is merely capable of measuring flow, maybe I could try to eliminate the mass of air, or the density ratio, from the equation. But I had better run fast before the truth catches up to me.

Prying around, I tried to reduce finding CFM by seeing how the actual flow (with and without boost) differed from the ideal flow potential dictated by the CID and my selected RPM of the engine. This would make the first equation above useful, even if for just a NA engine. If I found ideal airflow at a selected RPM for the 444 CID as a NA engine by first ignoring any VE factor, and then mulitiplied by the widely accepted NA VE of .85 to find an actual air flow, I might have something to multiply with when I determined a relative pressure ratio for the boosted TCI 444, provided I assumed that the NA version's pressure was atmospheric, and the temperatures were constant (or ignored). Now I am freely admitting ignoring something as important as temperature amidst the whine of the turbo's compression heat, but I'm thinking about the mitigating effects of the intercooler too...

Soldiering on, I first picked a peak "running" rpm a little higher than the rated peak horsepower rpm supplied by the engine manufacturer, based on my awareness that many of the people who would be interested in this study are running chips that manipulate fuel tables, boost allowance, and other parameters that in the end yeild greater dyno tested power at higher rpms. I mean like the top of the lungs yelling my truck has been doing lately on dyno's. I'll pick 3 grand on the tach.

Assuming intake, intercooler, and exhaust tracts have been modified and or optimized to handle the additional flow required to make use of the added fueling... the question then becomes if the air filter and housing it is contained in is capable of handling that flow demand. Basically, Jason's question.

Thus, from the first formula above:

[3,000 RPM x 444 CID] / [2 x 1728] = 385.42 CFM IDEAL Naturally Aspirated

385.42 x .85 = 327.60 CFM ACTUAL Naturally Aspirated

Where .85 is an accepted value for Volumetric Efficiency, and where Atomspheric Pressure is assumed to be 14.7.

When running at 3,000 RPM, boost is at 26 psiG. (oh yeah, did I mention my Banks chip?) To find the absolute pressure ratio, I did as follows:

[26 psig + 14.7] / 14.7 = 40.7/14.7 = 2.77

I then took the ACTUAL NA CFM of 327.60, and multiplied it by this absolute pressure ratio in the hopes of obtaining ACTUAL Turbocharged Intercooled CFM, or ACTUAL TCI CFM:

327.60 x 2.77 = 907.45 ACTUAL TCI CFM

My alarm bells began ringing, since this is a lot of air, but then I realize I've made no correction for temperature, and don't really know how to without more data. Haven't picked up my Autotap yet, doggone it. But maybe I can make fair assumptions. Ambient outside air, or pre inlet air on a cold air induction is say 77 degrees F, underhood air on a warm air induction filter system is at say 145 degrees F, delta T between inlet and outlet of intercooler is say 150 degrees F, and, uh, you'll have to help me guess how much heat energy the compressor is adding to the air. With my new wheel just instaled, I wonder how important the difference between wheels might have on heating the air too? Hmmm. Well, at least I have a boost guage that will give me a working knowlege of various boost pressures at RPMs under loads. Of course, the boost reading doesn't distinguish heat induced pressure rise from compresser induced pressure rise, and I don't know if heat induced pressure rise is really negligible or not, since the air is in constant motion.

Lot's to think about, and then it is so dynamic too. But back on track, I want to know the PEAK CFM. If I take the actual TCI CFM, and divide it by the Ideal NA CFM, I thought I might find a workable TCI VE that I could use in lieu of a NA VE... thus:

907.45 / 385.42 = 2.35

Definitely on the high end of the published VE ratios of TCI engines... or is it? I'm going to take a short cut here and just say I found that an inlet to outlet temperature differental ratio, in degrees Rankine (absolute temperature in degrees F + 459.67), proved to be about .8, then my TCI VE might move within a more commonly seen range of VEs that I found:

2.3 x .8 = 1.84 TCI VE, now with a SWAG absolute temperature ratio and the aforementioned psiA ratio taken into consideration.

I am working on one Part to this study on temperatures as they relate to our engines, and our airflow, that I will post at another time. That will explain the approach I am using to consider the Delta T from inlet to compressor, compressor to intercooler, intercooler to manifold. You can shoot holes in that when I post it later, in the mean time, let's finish with this target, it's big enough.

Getting back to my math process, maybe I could reduce steps by canceling terms in the algebra and saying that

TCI VE = {[PSIG + ATMOSPHERE] / ATMOSPHERE} x NA VE

But if I wanted to wake up and smell the coffee of adiabatic efficiency, (in this case, the heat gain from the compressor, figured with the heat reduction of the intercooler) maybe I could reasonable assume absolute temperature values at the critical places where I might expect delta T's to occur.

TCI VE = [IATA / MATA] x [MAP / BAR] x NA VE

Where:
TCI VE = Turbocharged Intercooled Volumetric Efficiency
IATA = Inlet Air Temperature Absolute
MATA = Manifold Air Temperature Absolute
MAP = Manifold Absolute Pressure
BAR = Atmospheric Pressure Absolute
NA VE = Naturally Aspirated Volumetric Efficiency

Yeah, I threw the NA VE back in there to account for the engine's pumping loss.

Now that all the swagging is done to come up with a turbocharged intercooled volumetric efficiency correction ratio, the formula above for naturally aspirated engines can be used, substituting VE with TCI VE. OK, fire away.

At this point, I have to remind myself that all I am really after is knowing what the maximum amount of airflow the 444 CID TCI engine may require on peak demand. So hey, why not ask the engine maker?

Well, the 1994.5 PSD, rated at 215 HP @ 2,600 RPM, uses 548 CFM @ 2,600 RPM. CFM ratings are usually given at peak HP. Reversing the math, I came up with a TCI VE of 1.6. In the ballpark ratio. But that motor used a TP38 turbocharger with an A/R of 1.15, and it didn't have a wastegate.

Our PSD's (in this forum) make more HP at higher RPM. We have a different turbo, hybrid if stock, with an A/R of .84 on the turbine and 1.0 on the compressor. And we are wastegated, so we are in the boost more, and earlier. (FYI: the Ford Truck Source Book is in error on the turbo specs, they haven't updated them.) And that is if we are stock. Many of us who are even interested in this detail have "a few adjustments."

So while I am waiting for International before making any statement about what our CFM requirements might be, I'd still like to plug in different RPMs and boost pressures that various folks notice with different chips, etc, to recognize this CFM demand in order to maintain an air/fuel ration in that "sweet spot," or 22-1. If our chips are dumping in more fuel, then we will need the air.

It would be nice and simple to eliminate filter candidates tested on Bank's flowbench in this manner. But air flow is not enough. The power is made from air density. For a given cube of air, I'd rather it weigh in like lead than like driftwood. That discussion is clearly another post on it's own.