Air Filter Study

[mdub]

Not intending to start a flame war here, but this is interesting reading... finally, someone has the guts to publish test results that confirm what common sense has already told us about oiled/re-usable air filter elements:

 

Air filter study

 

Of course, common sense says less air restriction has to come at a cost: compromised filtering abilities. What is more important, an "extra 5-10 horsepower" (yeah right) that you likely can't even notice on a 300 hp engine, or proper filtering to maximize your engine life? And then there's the convenience factor to consider, and the desire to keep your intake/throttle body as clean as possible. Interesting stuff.

[bigdogs]

I read that too from dieselplace and was surprised to see the AC one lead the pack. I know when it comes time to replace mine that is the one I'll use.

[Elwood 2000]

While looking at Chart #7, it shows that the AC Delco filter RESTRICTS more air flow while a filter like the K&N FLOWS more. This is exactly what they claim. They never claimed that they filtered MORE or BETTER than stock.

 

The question YOU, as a consumer has to ask youself is this: "Just how dirty of conditions is my truck going to really be in?"

 

If you use your truck in a dirty environment, keeping a closed system with a more restrictive filter is best, but if you are strictly on the pavement and your truck is driven in little dirt, I see no problems with an open filter or K&N "like-type" filter.

 

My guess is that the better flow comes from the "straight thru" design of the tube rather than the filter itself. Something else to consider is the basic principal of an engine. Suck-Squeeze-Blow. You can suck all you want, but if you can't discharge the gases, you will only really be able to suck what your exhaust can handle or what your engine is capable of producing, whichever is less.

[Blue-2001-Z71]

Here's a thought; how much damage is DUST really going to do on a MPI type engine? We're not running carbs where there are all sorts of jets and venturis to plug. The air really just runs down the intake ports into the cylinders where fuel is injected into it and ignited. As long as the air is being filtered of larger material (sand, dirt, bugs, rocks, etc) that could cause a FOD issue internally, I doubt that even long term dust ingestion is really going to run down the engine as long as someone running the K&N inspects and services the filter at the prescribed interval. I have almost 50K on the filtercharger in our STS and I have yet to see ANY problems develop from it. I have only had to clean/oil the filter once and have not even had the MAF sensor problems that seem to plague so many (not to dismiss these, there clearly is a problem in those cases). Maybe I'm just lucky.

[Black02Silverado]

One way to really see what is happening inside in relation to the filters your running is an oil analysis. Silicon is a good indicator of many things, one being how well your air filter is filtering and if any leaks in the intake system are present.

 

Very interesting study. Thanks for posting it.

[az'03Silverado]

Here's a thought; how much damage is DUST really going to do on a MPI type engine?  We're not running carbs where there are all sorts of jets and venturis to plug.  The air really just runs down the intake ports into the cylinders where fuel is injected into it and ignited.  As long as the air is being filtered of larger material (sand, dirt, bugs, rocks, etc) that could cause a FOD issue internally, I doubt that even long term dust ingestion is really going to run down the engine as long as someone running the K&N inspects and services the filter at the prescribed interval.  I have almost 50K on the filtercharger in our STS and I have yet to see ANY problems develop from it.  I have only had to clean/oil the filter once and have not even had the MAF sensor problems that seem to plague so many (not to dismiss these, there clearly is a problem in those cases).  Maybe I'm just lucky.

 

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Exactly. And, by the time my K&N filter damages my truck's engine, I (more than likely) won't own it anymore and won't care. I'll just enjoy the cool sound and extra pep while I have it.

[EZ Livin]

Although my truck already has a K&N from the previous owner, I'm skeptical that I would notice any difference. The most benefit is gained at full throttle and high rpm's. Since neither applies to the way I drive the truck, I'll probably switch to an AC Delco filter because it has the best efficiency and capacity plus the lowest quantity dirt passed.

 

[facn8me]

If I remember correctly, after some miles the K&N still flows better than paper but the surface dirt has made the filtering process better. resulting in many more miles between cleaning supposed to be 50k or more? correct me if I'm wrong.

 

 

I run K&N in my rides and don't rush out and clean them if I see a little dirt. cause I know after 10k I still have good flow. clean at 35-45k Paper I like to change 10k. K&N in my opionion is cheaper in the long run and less maint.

[mdub]

If I remember correctly, after some miles the K&N still flows better than paper but the surface dirt has made the filtering process better. resulting in many more miles between cleaning supposed to be 50k or more? correct me if I'm wrong. 

 

 

I run K&N in my rides and don't rush out and clean them if I see a little dirt. cause I know after 10k I still have good flow. clean at 35-45k  Paper I like to change 10k. K&N in my opionion is cheaper in the long run and less maint.

 

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The second chart shows “Accumulative Dirt Capacity” of the filters which is a measure of dirt holding/loading capacity before reaching the maximum restriction limit. This chart clearly shows oiled/re-usable filters are the worst in this category. Even if filtering qualities slightly improve as dirt accumulates, the oiled/re-usable filter quickly becomes more restrictive compared to paper elements.

 

According to these data, the oiled/re-usable filters should be maintained MORE often, not less often.

[facn8me]

I don't drive in dusty conditions(usually) and check for dust in the intake tube during oil changes. Never a problem for me. I run napa gold in the fleet cars at work. I have a k&n in my 96 monte and v8 blazer. but have a napa gold in the silverado. I won't do anything till it's out of warrenty. performance wise. I am actually happy with the performance of the silverado so I doubt that untill it's paid off and then lifted I will add anything. I noticed the wix ranked pretty high so if I believe it's good I should believe the k&n is bad. but I don't believe the k&n is bad. I run one in a blaster too. no dust in the intake even in sand. I run a uni also and can recomend them too. I was very intersted in that study but not completly swayed. I agree with you mdub by that study I should clean and recharge more often.

 

This is not alot of technical info is it?

this is per k&n web site in faQ The general rule of thumb is that the filter needs to be cleaned when the dirt build up gets as thick as the wire mesh. The usual interval is 30,000 - 50,000 miles depending on driving conditions. We recommend that you check your filter about once a year in normal usage.

 

i guess I have had reliability with k&n and paper. In my opinion for what it's worth. I could recomend either. A quality paper air filter propely serviced is probably the best bet but then I couldn't say "and a k&n when rattling off mods."

 

 

mods are 1986 S-blazer 350 10.5 to 1 2.02's comp 280h cam roller rockers air gap 650 dp maollry unilite and procomp coil mallory 140gph electric pump becool rad. flexalite dula elec. fans oil cooler trans cooler remote oil filter. hooker full length super comp headers. 2 1/2 inch with crossover pipe and delta flows. 1 1/2 hellwig sway 5/8 rear agr 12 to 1 gear box drilled and vented rotors. built 700r4 and a "K&N" see how good that K&N sounded at the end.

[mdub]

Agreed, the oiled/re-usable filter has a place on certain engines where every ~1% increase in horesepower counts. As the charts show, some are less restrictive when clean, which may affect the horespower only if the auto manufacturer hasn't compensated with an adequately large paper element.

 

I personally feel that dirt in an engine is bad, period. If it's an engine you plan on rebuilding often for racing purposes, etc., performance is most important, and reliability may be compromised. For my daily driver, and one that I want to feel good about selling to someone else, I lean towards keeping dirt out of the engine. The results of this study were very informative.

[facn8me]

I completely agree. ANY dirt in the engine is bad news. I do not doubt the test results. As said earlier very informative. I was shocked the k&n performed that badly. let alone the amsoil. Thier products are first rate. Your post has intriged me enough to check mine tommorrow and keep tabs for a bit.

[99GMCZ71]

After reading this study, the K & N filter is going in the trash and back to the AC Delco.

[PASTOR SCOTT]

Hey whats up with the filters ? I took out my K and N also and put back in the AC where can I see this test, and dose the AC flow or clean better ??

 

 

 

SCott

[mdub]

Hey whats up with the filters ? I took out my K and N also and put back in the AC  where can I see this test, and dose the AC flow or clean better ??

 

 

 

SCott

 

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You can see the results by clicking on the "Air Filter Study" link in the text of the first posting, or by clicking here...

 

Air Filter Study