This is a very comprehensive test of 9 air filters I stumbled upon. There is lots of real eye-opening data. It pretty much confirmed what I have thought all along about aftermarket performance filters; a lot of hype and very little filtering. Might as well run no filter at all, they just keep boulders out. Results of one test (course dust) were an AC Delco paper element allowed 0.4 Grams through the element and the K&N allowed 7.0 grams through and was the second quickest to clog. The Delco filter was the most restrictive but filtered the best and was the last one to clog. Take the time to study it, I know I'm going to.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

This is a very comprehensive test of 9 air filters I stumbled upon. There is lots of real eye-opening data. It pretty much confirmed what I have thought all along about aftermarket performance filters; a lot of hype and very little filtering. Might as well run no filter at all, they just keep boulders out. Results of one test (course dust) were an AC Delco paper element allowed 0.4 Grams through the element and the K&N allowed 7.0 grams through and was the second quickest to clog. The Delco filter was the most restrictive but filtered the best and was the last one to clog. Take the time to study it, I know I'm going to.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

Great Info., Thanks ;)

Come on guys this is good stuff!

Come on guys this is good stuff!

Makes a lot of sense. Do you know how filters work? Let me give you a quick lesson. You get higher efficiency filtration by decreasing the ability for smaller particles to get through. Most of your house filters will have an efficiency rating along with the SEA rating. The higher the efficiency the more particles at (0.3 microns) the filter will filter out. The tradeoff obviously is airflow. You can increase airflow by increasing the amount of "pleats" in a filter. This gives more filter "surface area" for dirt to catch on. (fills up in the pleats and clogs slower). More pleats equals longer life of your filter. So the higher efficiency the filter, typically more pleats to offset plugging time. K&N and other filters of this sort use a different approach. Less restrictive, less pleats, higher airflow, which obviously means more dirt will pass. Not rocket science. They add the oil to catch more dirt without restricting airflow, hence the "exponential" plugging curve (just have to wash it more often then you would have to change a normal unoiled filter, by design). If you want more airflow, and higher performance you need less restriction. If you don't want your engine to catch a cold use a more restrictive filter. How much damage can a 0.3 micron particle cause in an engine cylinder anyway. Not like we are trying to stop infections like toxic mold and legionella, like you said, just trying to keep the bolders out and increase performance.

Edit Comments:
Another test that would add some useable data would be how large were the particles that "passed" through the filter not how much.

I guess you are going to go out and by an AC Delco filter now and reduce your horsepower. (I guess their marketing scheme worked). You can make statistics say what you want. They tell me less horsepower.

Seen it before. Good stuff. ;)

I guess you are going to go out and by an AC Delco filter now and reduce your horsepower. (I guess their marketing scheme worked). You can make statistics say what you want. They tell me less horsepower.
No, but I know what filters I'm NOT going to buy to put in my +40k truck.

Has anyone determined what size and shape particle, made from what substance is harmful and what is not? I suppose we could all go around wearing surgical masks or respirators for hazardous environments to protect ourselves from particles that might harm us, but don't we have to first determine if we are in an environment that requires this?

I can breath just fine and live a normal life expectancy without that extra restrictive breathing gear.

My own anectodal experience suggests that filters can become "too much of a good thing," and that scare tactics are being used by some manufactures to make us put surgical masks on our engines when they are not needed.

I guess 450,000 K&N filtered miles on my F-250, 107,000 K&N filtered miles on my recently sold Expedition, and 15 years (yes, you heard that right) of off roading in my K&N filtered CJ-5 (on the same filter) in very dirty, dusty, muddy environment, don't count for much in this discussion of filtering out microparticles of unknown danger.

Has anyone determined what size and shape particle, made from what substance is harmful and what is not? I suppose we could all go around wearing surgical masks or respirators for hazardous environments to protect ourselves from particles that might harm us, but don't we have to first determine if we are in an environment that requires this?

I can breath just fine and live a normal life expectancy without that extra restrictive breathing gear.

My own anectodal experience suggests that filters can become "too much of a good thing," and that scare tactics are being used by some manufactures to make us put surgical masks on our engines when they are not needed.

I guess 450,000 K&N filtered miles on my F-250, 107,000 K&N filtered miles on my recently sold Expedition, and 15 years (yes, you heard that right) of off roading in my K&N filtered CJ-5 (on the same filter) in very dirty, dusty, muddy environment, don't count for much in this discussion of filtering out microparticles of unknown danger.
Quote;
SAE Technical Paper 942032: “It’s a commonly known fact that lubrication oil does not wear out mechanically, and if kept clean will maintain its lubrication qualities intact almost indefinitely”
Contaminants between 2 and 20 microns in size can be particularly damaging since they can disrupt hydrodynamic lubrication by entering wear surface.”

Guess there is a couple of ways to look at this but I mostly agree with FLCrusin. Damage to your engine from micron sized particles is probably IMHO the least of your worries. Me personally I will be getting the V3 CAI for its higher efficency not for its ability to filter out every last tiny particle. Now on the inverse I'm very concerned about oil and hydraulic flitration and will make every effort to have these fluids and filters replaced regularly. Metal fragments versus dust particles seems like no contest. If anyone has data to prove that long or short term use of less restrictive air filters has caused significant damage to an engine please post immediately.

Clearances in an engine can range approximately between 2 (~.001")and 22(~.009") microns. particles of this range can cause the most damage since they have the ability to get "wedged" between moving parts. The "boulders" that oiled gauze filters catch do very little damage but bead blast the intake tract and valves/seats.

Quote;
SAE Technical Paper 942032: “It’s a commonly known fact that lubrication oil does not wear out mechanically, and if kept clean will maintain its lubrication qualities intact almost indefinitely”
Contaminants between 2 and 20 microns in size can be particularly damaging since they can disrupt hydrodynamic lubrication by entering wear surface.”

Excellent observation. It is filtration in the OIL which is critical once you reach that "small is small enough" point in the airstream.

I think it is far more important to get the bad stuff out of the oil than to worry about differences in air filters. Get the contaminated oil out of there at 3,000 mile intervals and use high quality filters like Nissan's or Purolator or others proven to have superior filtration.

I'd much rather run a low restriction intake and change the oil religiously at 3,000 miles with a high quality very fine filtration OIL filter, than run an AC air filter and a Fram oil filter with 15,000 mile oil changes.

BTW, back in the '70's I ran a blueprinted but factory stock 340 Plymouth Duster on the strip. All specs were set to optimize performance yet stay in showroom stock class regs. It would pull the left front wheel leaving the line. 13.2's on street tires, 12.8's on slicks.

I used a dragstrip pancake foam air filter made by Mr. Gasket - extremely open - would only catch the really big stuff for sure. I drove it on the street like that. I was curious as to just how important restrictive air cleaners were to engine life. I kept the car for over ten years. Raced it regularly, drove it hard. It was also my daily driver, although the race spec heavy clutch was something of a pain at traffic lights. It got torn down regularly for tech inspections, and for us to monitor engine wear.

The valve springs were shimmed so that valve spring pressure was at the maximum legal, allowing a few more rpm's to be squeezed out of the engine before approaching valve float. Manual tranny shift point was 6,700 rpm with hydraulic lifters!

Because of the spring pressure, and perhaps some torture to the valve train, the cam would wear a lobe down and produce a miss on one cylinder every 15,000 miles, just like clockwork. We'd pull the cam and replace it, inspecting everything else. The bottom end never did show any significant bearing wear and cylinder bore remained in specs the entire time I owned that car.

I must say that clutch life was poor, however!

How did this engine last so long despite its output, regular racing and relatively high mileage for the '70's? I think two things. Oil and filter were changed every 1,000 miles! Yes, I said every 1,000 miles. And the engine was blueprinted and balanced, thereby eliminating sloppy tolerances.

Today's engines, especially Nissan's come very close to blueprinted quality. Tolerances are far tighter than they were thirty years ago. Oil is better quality and additives last longer.

My point is that getting the big stuff out of the intake stream is important, but getting the little stuff out of the oil and replacing it at sensible intervals is more important than fixating on how small the microparticles are on the intake side.

Just one opinion.

Clearances in an engine can range approximately between 2 (~.001")and 22(~.009") microns.

1 micron = 0.00003937 inch

http://www.ilpi.com/msds/ref/distanceunits.html

I believe you may be off a bit in your conversion. I agree with your numbers regarding engine clearances.

In automotive machine shop operations we do typically operate in tolerances of "tenths", meaning one ten thousandth of an inch - .0001. In grinding a crankshaft, for instance, we want to stay inside the center of the general tolerance, which would be plus or minus 1/2 thousandth - .0005 inch and be round with in that "tenth" range - meaning round within .0001 inch.

Bearing clearances are typically one to two thousandths of an inch. More likely one thousanths of an inch with modern engines. How many micron size particle do you say it would take to seriously occlude oil flow to the rod or main bearings in such an engine?

I believe it would take 25.4 microns to close a .001 space. And we began this discussion by theorizing that a .3 micron particle might produce serious engine harm. Such a particle is 0.0000118 inches.

We do use polishing belts with abrasives much, much larger than that to "microfinish" bearing surfaces. They do not reduce the size of the surface, but do make it smoother.

Am I missing something here?

1 micron = 0.00003937 inch

http://www.ilpi.com/msds/ref/distanceunits.html

I believe you may be off a bit in your conversion. I agree with your numbers regarding engine clearances.



You are absolutely right, I missed a decimal place, looked at it as 4/10ths. Still don't like any kind of dirt in my engine though. Also the clearances under load are not concentric.

Now, for us who are not mechanicly ( wrong spelling)inclined, what filter should we use?. Do I need a filter if I am installing the volant 3? :confused:

Now, for us who are not mechanicly ( wrong spelling)inclined, what filter should we use?. Do I need a filter if I am installing the volant 3? :confused:

To max your power go aftermarket, just change your oil often. To play it safe like (a worry wart) me stay with the OEM style. Also it depends if you spin your engine at higher RPM's a lot, that is where the flow advantage is.

Use the filter that comes with the Volant. Under normal conditions it will go a long time before it needs cleaning. When it becomes dirty clean and reoil according to the directions on the recharge kit. One reason I made the clear cover on my Volant was to be able to monitor the condition of the filter without taking the cover off.
As far as filtration is concerned, I agree with Armada. I think the oiled gauze type filters work OK if, like any air filter, they are properly maintained. The oil filter and condition of the engine oil is the most important thing to worry about. I change oil and filter every 3,000 miles, or less. It is very cheap insurance against engine wear. I don't care how good the extended change interval oils are, there is no way I would ever go 15-25,000 miles between changes, which some oil makers say is OK.

How is the clear cover sealing? is it as good as the volant factory one? I change oil at the dealer every 3750Miles, according to the manufacturer recomendation. and I do not know what kind of oil they use. should i be changing oil every 3000miles instead?

My clear cover seals much better than the factory cover.
The oil change at 3750 is fine. I change mine at 3000 because it is cheap. My dealer charges me only $9.95 for a oil and filter change, and fills all other fluids if needed and checks the tires. No way I can buy oil and filter that cheap, and I don't have to deal with disposal or do the work!

My clear cover seals much better than the factory cover.
The oil change at 3750 is fine. I change mine at 3000 because it is cheap. My dealer charges me only $9.95 for a oil and filter change, and fills all other fluids if needed and checks the tires. No way I can buy oil and filter that cheap, and I don't have to deal with disposal or do the work!

My dealer charges me 29.95 for the oil change, and do nothing else. anyway, back to the clear cover, was it a pexy glass? and how where you able to have it seal so good?

This discussion got me to thinking about filters. I want high performance, but don't want excessive wear from dirt entering through the air filter. The best indicator of dirt getting into the engine is the amount of silicon in the oil. So I did a little research of engine oil testing at Blackstone Labs. I looked at the silicon levels (in parts per million) from 12 different oil tests from the Nissan 5.6 engine. Some engines had the stock air filters, some had the gauze type.

The average PPM in silicon in the oil using stock filters was 18.379 PPM, with an average oil change interval of 5.35K miles.

The average PPM in silicon from engines with oiled gauze filters was 12.0 PPM, with an average oil change interval of 5.55K.

This workes out to 3.435 PPM of silicon per 1K miles for the stock filter, and 2.162 PPM of silicon per 1K miles for the oiled gauze filter.

So we can see in these random tests the silicon levels in the engine oil of vehicles using oiler gauze filters was lower than stock filters. I can't say this is solid data, but actual tests in actual service means more to me than blowing dust through filters in a lab.

I am not saying everyone should rush out and buy an aftermarket filter; that is your choice.

My Volant will stay in use.

It is generally accepted by nearly all camps that oil/gauze filters do not filter as well as pleated paper, but you oil data shows just the opposite? Or am I misunderstanding what you are saying?

[QUOTE=Armada] And we began this discussion by theorizing that a .3 micron particle might produce serious engine harm. Such a particle is 0.0000118 inches.
QUOTE]
Actually this began with the amount of "course dust" passed in the test which the greatest percentage was in the 20 - 80 micron range which the K&N allowed 7 grams through compared to the best pleated paper element at 0.4 grams.

It is generally accepted by nearly all camps that oil/gauze filters do not filter as well as pleated paper, but you oil data shows just the opposite? Or am I misunderstanding what you are saying?
I am just reporting what I found by looking at the oil analysis from Blackstone Labs. I got the results of the 12 tests from this thread:

http://www.clubtitan.org/modules.php?name=Forums&file=viewtopic&t=53

To compare the silicon results I chose the results of 12 tests where the poster stated which type air filter was used, stock or oiled gauze. Of course I couldn't compare results when the poster didn't tell what type filter was used.

As I stated, you can't say that this data is positive proof, and I'm not trying to prove which type filter works best. I do know that an increase in silicon in oil is usually an indication of dirt coming in through the air filter.

I am suprised at what I found. I expected the oiled gauze filters to show a higher silicon reading than the paper filters. One thing that may explain this is the fact that new engines have higher silicon readings at first. In these tests the engines with the aftermarket filters may have had more miles on them and would show a lower silicon reading with either type filter.

I think the main point here is that it doesn't look as if we will see much difference in the silicon readings with either type filter as long as both are maintained properly.

That's a nice study of the data on the silicon content of analyzed oil in our 5.6L engines. I concur that silicon content is a good indicator to study if you are looking for potential damage.

Taking the paper filter side (for a change) silicon content does not tell us anything about the size of what is floating around in our oil.

But taking the oiled gauze filter side, I agree that if there was significant quantity, it should show up in increased silicon content with the K&N type filters, and it did not.

This points out one of the shortcomings of the study that started this thread. Did anyone notice that the paper filters were not tested for their ability to pass small particles? The designers of that study subjected the K&N to testing for large and small particles, but the others just for the large particles.

We are left to speculate as to just how well the paper filters would have done on the smaller particles. That's not very good science and leaves me scratching my head as to what the true objective of that study was. Perhaps those other filters would have done a better job of stopping the little stuff, but maybe not.

And we do not know if the design characteristics for the filters on those Duramax engines are similar to those used by the same manufacturers for our engines -- i.e., number and depth of pleats, amount of surface area, and air flow rates, among other things. They may hold true for Duramax diesels, but do they for 5.6 Nissan gas engines?

SCR38's review of the silicon content analysis on our engine model suggests that the total difference, taking all types of contaminants into consideration may be very slight.

And still, we have no clear answer as to what size particles are actually harmful. My experience is that very large particles, especially those able to survive the extreme heat of combustion (sand, silica), have an extremely abrasive effect on cylinder walls. Even the most open of the filters at issue do a good job of stopping these type particles.

Properly executed cylinder machining, either at the factory or in the aftermarket, produces a nice "crosshatch" pattern on the cylinder walls which allows oil to accumulate and remain within the "grain" (not a technically correct concept, but you get the idea). Rings seat faster and engines last longer. Rough abrasives quickly destroy this pattern, produce excessive wear to the soft aluminum piston skirt, the rings and the bore. Bluntly, this is BAD.

There is no compelling evidence, however, that small microparticles produce this harm nor that they adversely affect the life of crank journals or bearings.

But just one larger particle, if it gets into the bearing surface is absolutely fatal to main and rod bearings, because that bearing surface is only a few thousands of an inch thick.

Again, the trick, in this one guy's opinion, is to use high quality oil, high filtration oil filters, and change oil and filter frequently.

Within a broad range, air filters play a much less important role, IMHO. It seems to me that all of the readily available major brand air filters, including the oiled gauze types at least meet these minimum requirements. So if you are getting the bad stuff out with the oil filter, then use whichever type of major air filter you prefer. High flow rates will produce a little more dirt, which your oil filter should pick up, and may yield a small increase in power. High restrictions air filters will produce marginally less power but may give you some peace of mind.

It's your truck. There are no clear absolutes on this. I like the cotton gauze filters and will continue to use them.

Another consideration is the bypass pressure of the filter. Most filters open their bypass valves at about 17psi. What no one talks about is the pressure drop in the system with the bypass open or how soon most filters clog to the point of 17psi. On the face of it, my engine goes past 17psi on the crankup. So does that mean that since 99.999% of the time, since my engine oil pressure is above 17psi, that it is almost never filtered?

Based on this non understanding, and knowing that synthetic oil holds particles in suspension much better than dino oil which allows them to settle out, I'll stick with synthetic.

Also, anyone know at what pressure the anti drain back valve shuts? And since the anti drain back valves are made of different compositions (black/grey/orange) do any of them truly prevent drain back?

Amazing that people will pay more attention to their oil and filter regarding their lower end, and accept less when it comes to the upper end - rings and valve seats - especially on an engine that is 32 valve. Compression will eventually suffer.