Air Filter Study Completed!!!!!

On another diesel forum the members banded together to conduct an independent study regarding air filters for the Duramax Diesel. There is a lot of marketing hype surrounding certain aftermarket air filters and we wanted to know if the filters could stand up to their claims. Claims of "superior" filtering ability and dirt holding capacity are among some of these claims. Additionally, many filters are claimed to allow for "better" air flow giving you more horsepower.

This claim of better flow giving more horsepower is a debate all its own, but dyno tests run with a paper filter vs. NO FILTER AT ALL have shown NO INCREASE IN POWER OUTPUT. Therefore a filter with "better flow" will not only give you no increase in performance, it will also let in a lot of dirt while doing it.

The following data is provided by Testand Corp. in Rhode Island. Testand makes the $285,000 machines that perform the SAE J726/ISO 5011 air filter test standard. Any air filter that wants to be tested for performance and efficiency uses this test. These tests cost $1,700 per filter when done by an independent laboratory. Testand Corp. was interested in the comparison study and agreed to do the study for us.

Every filter listed was tested in an identical manner according to the SAE/ISO test standard> Here are the results:


In the order of EFFICIENCY (ability to filter dirt) the results are as follows:

FILTER % EFFICIENCY

AC Delco OE 99.93%
Baldwin paper 99.72%
No name pargain paper 99.32%
AFE Pro Guard 7 panel filter 99.23%
WIX/Napa Gold 99.03%
Purolator paper 98.73%
Amsoil, new style 98.63%
UNI 97.93%
K&N 96.80%


FLOW RESTRICTION from best to worst. Remember, 27.7 inches of water = 1 psi. So, 1 inch of water = .036 psi. The worst (AC Delco) at 6.23 in. water and the best (K&N) at 4.54 in. water is a difference of 1.69 in. of water or a "whopping" .0608 psi. Virtually negligible.

In order from least restricive to most:

FILTER RESTRICTION in inches of water

K&N 4.54
Mystery bargain 4.78
AFE Pro Guard 4.99
Purolator 5.05
WIX/Napa Gold 5.06
UNI 5.40
Baldwin 5.71
Amsoil 5.88
AC Delco 6.23


DIRT HOLDING CAPACITY. From best to worst. This is the AMOUNT of test dirt it took to create an ADDITIONAL 10 inches of restriction. At that point the test is terminated. This is an indication of HOW LONG a filter is good before it must be cleaned or replaced.

FILTER Dirt Holding Capacity

AC Delco 573.898 grams
WIX/Napa Gold 447.366 g
Purolator 388.659 g
Baldwin 388.154 g
UNI 374.638 g
Mystery bargain 350.402 g
AFE Pro Guard 7 232.516 g
K&N 211.580 g
Amsoil 196.323 g


TOTAL DIRT PASSING THE FILTER DURING THE TEST. This is how much dirt your engine will take in if you use the filter for the duration that would cause the filter to become "dirty" enough to need replacement or cleaning. The "Dirt Passing The Filter" is the dirt collected by the "POST FILTER" during the SAE/ISO test.

In order from best to worst, the filters performed as follows:

FILTER DIRT IN GRAMS PASSED

AC Delco 0.4g
Baldwin 1.1g
AFE Pro Guard 7 1.8g
Mystery bargain 2.4g
Amsoil 2.7g
WIX/Napa Gold 4.4g
Purolator 5.0g
K&N 6.0g
UNI 7.9g

NOTE: During the test the Purolator was reported to have had a seal failure which gave it higher than expected dirt passing.

I hope this data is as eye opening for you as it was for me. SPICER

Spicer,

Awesome Test! Thanks for your excelent work and for posting the results! http://forum.thedieselpage.com/ubb/icons/icon14.gif

Just dumb luck but I'm glad I've been using AC filters on my 03 since new. :eek:

Spicer, A couple questions. Was the testing done on a Chevy/GM Duramax (year/model?) or on a bench rig? And is the AC Delco our OEM filter? Have to say, by seat of the pants feel, the UNI wasn't doing much for me...

Excellent report,
Ken

Quote:

---

Originally posted by silverback:
Spicer, A couple questions. Was the testing done on a Chevy/GM Duramax (year/model?) or on a bench rig? And is the AC Delco our OEM filter? Have to say, by seat of the pants feel, the UNI wasn't doing much for me...

Excellent report,
Ken

---

The tests were done on a $285,000 air filter testing machine made by Testand Corp. This is a machine that controls all variables including airflow, temp., humidity, dust feed rate, dust temp. and humidity, etc...and then weighs all components (filter, post-filter, test dust) to 1/1000 gram.

The filters tested were the brands listed above and ALL were the Duramax Diesel filter(size/model#).

Your seat of the pants intuition is correct, because NONE of these air filters will add power. NONE! They look cool, cost a lot and add dirt to your oil. If you are good with that then stick with them. SPICER

Looks like it is time to dump the Amsoil foam filter and just stick with the AC/Delco original.

Spicer - Thanks for pulling all this together.

Spicer,
Great effort, Results are a little bit of an eye opener, I run and always will run a K&N. There is ONE thing they didn't check -- and it is important up here in the rain belt -- how these filters perform soaking wet. With the way the Intake is set up on these trucks WATER is a factor.
Al

Turbo Al - You must have an '01. On my '02, they (GM) sealed off the hole in the fender well. While not impossible for water to get into the filter, it is a lot harder with the fender wall hole sealed.

I and probably MANY others would love to SEE the report, what "Other Diesel Website" is it? I don't think the Admins here try to hide the names of other websites from us, and wild-goose-chasing ain't my thing [img]smile.gif[/img] This way, we can see the report copy??

Questions from a skeptic who's seen alot of "tests" come and go, getting disproven or discredited as advertising/anti-advertising hype on the sly:

At what airflow rate were the filters tested?
To standardize it and give the pressure drop (in inches of water) they must have a specific airflow rate in CFM or lbs. per hour of air.
This is important in determining if the 40% worse airflow of the worst filter (vs best) is or is not significant.

Saying that 40% worse airflow won't affect performance goes against engine performance building experience of race teams and companies the world over.

If you deny this then here's a challenge for YOU:

IF you, and everybody reading this, believe there is absolutely NO performance loss, based on "0.06 psi loss" pre-turbo...

ALL of you go out and PUT AN AIRFILTER ON _YOUR_ truck that is only 1/10 the size of the current one, maybe a valvecover breather filter. Then you will "ONLY" be losing 0.6 psi pre-turbo...right? Or, put layer after layer of filter material around it so you get 99.99999999999% filtration efficiency, because it obviously hurts nothing.

Why NOT put in a breathercap-size airfilter, if you believe? Too hard? Imagine all the money saved buying really small filters! Dumb ol' GM, putting on a filter that apparently could be 40% smaller...well, based on 0.06 psi, it could be 16 times smaller and only cost a measly 1 psi pre-turbo restriction. GM, Ford, Chrysler, everybody who has bought WHATEVER brand bigger airfilter and gone faster, all those race teams the world over...sure are dumb. Include me, my truck went from (an average of 3 passes each) quartermile 16.71@79.0mph to 16.60@79.8 mph; 0-60 went from 9.14 down to 8.94 seconds, JUST by putting on a [Brand X] performance airfilter. Amazing? No, but about a 10+ hp increase...
10hp here, 10hp there, pretty soon it adds up! [img]smile.gif[/img]

Again, what is the airflow rate tested at in CFM?
If it's around 453 cfm (the amount of air needed to make 300 crank hp) it is to be considered; but many of us may have Juice boxes etc and be making over 500 crank hp (755cfm)...

Is there a website or page we can see the PHOTOCOPIED test report from the company? If it costs $1700 each filter, and the machine cost $285,000 there MUST be at least ONE scannable sheet of "Test Report" we can all see.
Probably the SCANNED PICTURE of the test report will give the CFM airflow rate and the picky "Devil is in the Details" stuff it takes to convice us Skeptics [img]smile.gif[/img]
Hate to see all that expensive testing and machinery go to waste without so much as one sheet of paper produced to LOOK at.

Thanks for the info, once we see the real report and can judge ourselves! [img]smile.gif[/img]

"TRUST, BUT VERIFY"--Ronald Reagan

Quote:

---

Originally posted by xwing:
I and probably MANY others would love to SEE the report, what "Other Diesel Website" is it? I don't think the Admins here try to hide the names of other websites from us, and wild-goose-chasing ain't my thing [img]smile.gif[/img] This way, we can see the report copy??

Questions from a skeptic who's seen alot of "tests" come and go, getting disproven or discredited as advertising/anti-advertising hype on the sly:

At what airflow rate were the filters tested?
To standardize it and give the pressure drop (in inches of water) they must have a specific airflow rate in CFM or lbs. per hour of air.
This is important in determining if the 40% worse airflow of the worst filter (vs best) is or is not significant.

Saying that 40% worse airflow won't affect performance goes against engine performance building experience of race teams and companies the world over.

If you deny this then here's a challenge for YOU:

IF you, and everybody reading this, believe there is absolutely NO performance loss, based on "0.06 psi loss" pre-turbo...

ALL of you go out and PUT AN AIRFILTER ON _YOUR_ truck that is only 1/10 the size of the current one, maybe a valvecover breather filter. Then you will "ONLY" be losing 0.6 psi pre-turbo...right? Or, put layer after layer of filter material around it so you get 99.99999999999% filtration efficiency, because it obviously hurts nothing.

Why NOT put in a breathercap-size airfilter, if you believe? Too hard? Imagine all the money saved buying really small filters! Dumb ol' GM, putting on a filter that apparently could be 40% smaller...well, based on 0.06 psi, it could be 16 times smaller and only cost a measly 1 psi pre-turbo restriction. GM, Ford, Chrysler, everybody who has bought WHATEVER brand bigger airfilter and gone faster, all those race teams the world over...sure are dumb. Include me, my truck went from (an average of 3 passes each) quartermile 16.71@79.0mph to 16.60@79.8 mph; 0-60 went from 9.14 down to 8.94 seconds, JUST by putting on a [Brand X] performance airfilter. Amazing? No, but about a 10+ hp increase...
10hp here, 10hp there, pretty soon it adds up! [img]smile.gif[/img]

Again, what is the airflow rate tested at in CFM?
If it's around 453 cfm (the amount of air needed to make 300 crank hp) it is to be considered; but many of us may have Juice boxes etc and be making over 500 crank hp (755cfm)...

Is there a website or page we can see the PHOTOCOPIED test report from the company? If it costs $1700 each filter, and the machine cost $285,000 there MUST be at least ONE scannable sheet of "Test Report" we can all see.
Probably the SCANNED PICTURE of the test report will give the CFM airflow rate and the picky "Devil is in the Details" stuff it takes to convice us Skeptics [img]smile.gif[/img]
Hate to see all that expensive testing and machinery go to waste without so much as one sheet of paper produced to LOOK at.

Thanks for the info, once we see the real report and can judge ourselves! [img]smile.gif[/img]

"TRUST, BUT VERIFY"--Ronald Reagan

---

In the pasr the mere mention of ***********.com has warranted editing. We'll see if it happens again.
Go to the "first generation Duramax diesel" thread and look for the biggest thread. All the details are within.

I posted on this forum and tried to get involvement from here for the study. One reply.

The data is fresh and faxed copies from Testand Corp. are all I have until next week when the original copies arrive.

At a time in the near future the data will be scanned, compiled and given a link for all to see.

I am a firefighter. I don't sell filters and don't personally know anyone who does. I got ****ed off at vendors praising products with no evidence of their fantastic "super-filter" claims. I was burned for $50 on an Amsoil. I was told it was the best. Then when my silica levels were high on my oil sample I was told to buy a UNI from that same vendor. I could have been like the flock and bought one. Instead I looked for a way to verify or discredit these overinflated claims. It was about 9-10 months of trying to do tests myself and learning all about the SAEJ726/ISO 5011 air filter test standard. Then I called Testand Corp. and a long story short they loved the idea of a comparison study and offered to do the study for us.

The test was run at a cfm based on the filter application and according to the SAE/ISO standard. For this test that value was 350cfm.

Your 40% worse airflow is a miscalculation. 27.7 inches of water = 1psi. Atmospheric pressure is 14.7psi or 407.19 inches of water. The AC Delco had 6.23 in. water restriction and the K&N had 4.54 in. water restriction for a difference of 1.69 in. water. 1.69 in. water equals .061psi. The atmoshere provides 14.7psi, so .061psi is a difference of .415%. I suppose if you need the .415% better airflow you'd better stick with the K&N.

Thanks Spicer and Ken at Testand for doing the test

Studies like this can be helpful, but I know that a new AC air filter will set the filter-minder a notch or two after a full-on run in my completely stock 2001 GMC, and that ~19 psi is the max boost pressure produced. With either an Amsoil, Uni or any of the performance gause elements, the filter-minder doesn't budge and my turbo can produce up to 23 psi. All dyno runs, 0-60 and 1/4-mile tests I've participated in have all improved with a free-er flowing air filter.

This tells me that differences in air filter media (having variations in restriction) can and will produce a change in power potential - depending on air filter media type.

Perhaps George Morrison can post some data from the voluminous quantity of oil analyses he's participated in, and share what he knows about air filter brand/media type and their relationship to silicon concentration in the engine oil.

AJ.... I don't remember an email from you inquiring about my participation in this test. We're always looking for good test and comparison data that is both reproducible and defendable.... And I might add, The Diesel Page pays for good work.

MP

[ 07-19-2004, 03:01 PM: Message edited by: More Power ]

My filter minder snapped in the other day with an AFE std variety element installed. Definitely moving serious air!

FWIW, I've had the UNI in my stock box for many miles now. Silicon in single digits.

When I swapped to the AFE intake, I realized that my filter minder was split (I knew it had cat's eyes in it) so I gave it a wrap with electrical tape for now. First time I checked it, it was set off, so it obviously was leaking before.

Quote:

---

Originally posted by kennedy:
My filter minder snapped in the other day with an AFE std variety element installed. Definitely moving serious air!

FWIW, I've had the UNI in my stock box for many miles now. Silicon in single digits.

---

When a truck is on a race track and it is modified out the wazoo, a more porous air filter MAY help. Data for this on a dyno should be very easy to achieve. However, if you are NOT on the race track and/or you are NOT heavily modified a paper filter will give you NO LESS power than a UNI, K&N or for that matter NO FILTER AT ALL! It has been done. All you will be doing is bringing in more dirt.

JK, If your silica readings are low that is great. It is NOT because you use a UNI. Bypass filter or clean air may be the reason, but not the UNI.

For every 500g of dirt encountered, the AC Delco will let 0.35g of dirt into the engine. The UNI will let 10.35g of dirt into the engine and the K&N 16.00g of dirt. That means the UNI is allowing 29.57 Times as much dirt into your engine as an AC Delco. Similar results with even a "cheap" paper air filter.

We all make choices. Informed choices are better than uninformed. SPICER

[ 07-19-2004, 09:24 AM: Message edited by: SPICER ]

Must be the air then as ferrographic as well as spectrographic analysis history supports exceptionally clean oil. This is true for before and after bypass filtration additions. The major difference that I saw with the bypass filtration was soot dropped.

I stay off of gravel as much as possible, but living in farm country I see a lot of "droppings" on the raod from the various vehicles leaving fields etc. I also have 1/2 mile of gravel to travel to get to blacktop.

Is anyone gonna send this data to the various vendors to get their input? It would be very interesting to see what AMSOIL, K&N, UNI, etc. would have to say about this. I'm stickin' with my AMSOIL for now, but I must say I am much less confident than I used to be concerning this filter.
JP

Quote:

---

Originally posted by kennedy:
Must be the air then as ferrographic as well as spectrographic analysis history supports exceptionally clean oil.

---

Must be. SPICER

Heartbeat Hauler wrote Is anyone gonna send this data to the various vendors to get their input? It would be very interesting to see what AMSOIL, K&N, UNI, etc. would have to say about this.

Excellent question. Seems like another round of testing might be in order. Let the companies mentioned above hire Testand to perform another set of tests. Let the Air Filter experts configure a representative test (if they think the current one is inadequate) Heck, Spicer mentioned that each test cost about $1,500. Thats prohibitive for "Average Joe" citizen. But get a couple of companies together to pool some marketing dollars and thats nothing at all. If they cannot back their product up with some independent testing, then the product must not be worth much. Just My Humble Opinion. Thanks again SPICER. (It will be interesting to see what "tests" fall out of these filter manufactures files or archives!!)

Some time ago, I set out to get some testing done, similar to this. The cost scared me away from it. MP offered to pay before I found out the cost, but I didn't think he would go for the amount that I found to be necessary. Unfortunately, I never asked him about it again. Southwest Research runs this kind of testing regularly, and is a very reputable source. Their cost was considerably higher than reported here.

Having done some research, the SAE J726 test procedure has some problems. Although it is the current "industry standard", it is known to have problems with repeatability. The box design is suspect.

K&N (I know, because I discussed this with their engineers at SEMA 2003) hired Southwest Research to do SAE J726 testing comparisons for them. The results were significantly different than what has been reported here.

As for the "no filter at all" comment regarding performance...

I guess my ET slips from my old 67 Camaro don't really count as real data. Hmmm.... I could pick up three to four tenths of a second in the quarter mile by removing my air cleaner. I guess that was just in my imagination. :rolleyes:

Ron
Have you made it back yet?

Greg

Yep, rolled in about 8:30 this morning.