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Pro's and con's of after market airfilters.

Discussion in 'Engine Compartment' started by Sat-Chit-ananda, Dec 24, 2010.

  1. Filtration is the main duty of Airfilter not supplying air at the cost of filtration,Most of tests and beliving my own eye's I felt cortoon gauze filters is not good at it's primary job of filtering.

    I came across Pippercross product,which does good job of filtering and ~30-50% more air flow compared to paper filter.
    It's reusable filter,claim is for 240000 kms of life.

    I understand Foam filters are used where dirt filtration and air are important, example off-road applications
    Until few years back I could see most of vehicles had foam filters,But I guess now a days they have been sidelined in favor of paper filters,may be to create more revenue for ASS centers?

    Foam Filter explained(from Pippercross site)

    The heart of the unique Pipercross air filter is a specially developed polyurethane foam which acts as the filtration medium, having both a higher performance and life expectancy than paper.
    Pipercross foam reticulated cell structure

    Pipercross reticulated foam is created by a chemical reaction, then placed in a gas-filled combustion chamber where controlled explosions burn away cell walls in the material to form a skeletal cellular structure which is strictly quality controlled.
    This process ensures that the foam consists of tiny open cells which trap contaminants.

    The cell size of the foam, its porosity, is measured in Pores Per Inch (PPI). Pipercross air filters use up to six layers of foam with varying porosity, which descend in pore size in the direction of airflow.
    Some layers are flame laminated with a nylon mesh in between, to produce a fail-safe interface without restricting air passage through the material - as would be the case with conventional bonding methods.
    Pipercross triple layer foam cross-section

    The Pipercross filter's long lifespan is due to the dirt storage capacity of the foam cells which means that no air passage is blocked until all the cells in a layer of foam are completely filled. Our air filters are designed to hold contaminants in the filter's outer layers, with the inner layers acting as a secondary measure to ensure an exceptionally high level of engine protection.

    Foam filtration explained varying outer surface finishes are employed to give optimum results in different environments. A dry liner of coarse material, or profiling designed to increase surface area, are two such finishes used by Pipercross.

    -Sat

    foam_cross_section.png

    panels-and-box.jpg
    Last edited: May 24, 2011
  2. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    The best i've ever seen are the UNI Foam Filters. Leaders in foam filter technology. Best airflow and filtration. ( I sound like a UNI salesman i think :p)

    Gurjinder.
  3. Nope you don't sound lime salesman:) Are these uni foam filter available in India?

    -Sat
  4. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    Nope Sat. E-bay is one route.

    Ron Chinoy of Bangalore ( famous as a RD350 tuner) imports them too.
  5. Dilip_dmk

    Dilip_dmk Superiore

    Messages:
    649
    Delhi, India
    New Delhi
    Grande Punto 1.2
    So , this sums up as - Pipercross filters are way better than the K&N filters ....

    How mch improvement in the performance and FE [after using these filters] could expected ?
    THey only come as stock or do they come as conical type also ???
  6. drifter

    drifter Regolare

    Messages:
    310
    London/Mumbai
    No they are not. Pipercross filters are s**t. I have had well over 100 on our dyno and none of them showed any improvement. As much dirt was found after the filter as with other filters. On the performance side they even took power away against standard.

    When the Pipercross filters see a couple of years they tend to disintegrate, which means dirt and foam will get into the combustion chamber.

    I have never seen a cotton gauze filter disintegrating, whether K&N or any other brand. I have had thousands and the dyno.

    I run on all my cars cotton gauze filter elements (This includes the track cars, which were shared ownership).
    Last edited by a moderator: May 25, 2011
  7. N Kiran

    N Kiran Staff Member Janitor

    Messages:
    1,518
    Hyderabad
    @ Drifter : Which Filter brand do you suggest? What would be the advantages of the same over the stock as well as other brand filters? What would be the price of it?
  8. drifter

    drifter Regolare

    Messages:
    310
    London/Mumbai
    Foam filters are the worst of all whether oiled or not. This applies to replacement filters as well as AIRs.

    Paper filters are much better and depending on the make they are quite even with cotton gauze filter elements. Unfortunately they loose flow capability much quicker than cotton gauze. Also cotton gauze is used for AIRs where paper filter elements rarely can be found.

    The filter medium is not the only criteria. The shape is evenly if not more important. This is wherer AIRs score points over standard set-ups. The attached hosong in an AIR does the other part to enhance flow and therefore performance.

    One other filter medium to use is the electrostatic ones, which are very expensive and need regular maintenance, which is why they are only used in professional racing.
  9. Extract from site http://www.vmaxoutlaw.com/tech/air_filters.htm,worth reading.

    All filter OEM's test their filters on a test jig, with a calibrated vacuum source (pump, downstream vacuum gauges, test vacuum gauges) and a calibrated dust feed mechanism. For my air filter evaluation project, I was interested in two data points; filtration efficiency and air filter airflow rates, with a weighting of conclusions in favor of filtration over airflow.

    1) I eval'ed publicly-available test data for pleated-paper, oiled- gauze, and oiled-foam air filters; I was most interested in small and large particulate filtration efficiency AS EXPERIENCED FROM TIME OF FILTER INSTALLATION. This approach takes into account the initial dust load-up characteristics of each type of filter and provides some feedback as to the possible service life of each air filter.

    The oiled foam filters seemed to show much better INITIAL filtration efficiency that either paper or oiled gauze, and filtered at a constant high rate of efficiency until the filter clogged, at which point the filters failed. Failure of the filter was marked by a significant decrease in filtration efficiency, as a result of the filter media collapsing or the filtration media simply allowing the particulate to be pulled thru the media unimpeded due to media saturation. The oiled foam filters appeared to hold significant particulate in the filtration media before vacuum levels (downstream intake restriction from filter clogging) rose to unacceptable levels and the filter failed. The vacuum level at which the filter would fail was lower than pleated-paper air filters, but higher than oiled-gauze filters. The thickness of the foam material appears to give it some self-bracing capabilities. Filtration efficiency was consistent for both small particulate (< 10 microns) as well as larger particulate.

    The paper filter tests showed a relatively poor out-of-the-box dust filtration efficiency until "loaded" with a certain level of dust; then their filtration efficiency rose to quite good levels. They did clog more quickly than the oiled foam, but did not fail catastrophically upon filter failure. Filter failure was marked by a refusal to pass air; the filter's mechanical strength allowed the filter to remain intact. (This is the property which makes them ideal for earth-moving equipment and industrial motors; the motor will run like shit when the filter is clogged but the filter will not collapse from to the high intake vacuum caused by the filter restriction. The pleats give the filter a very high mechanical strength....) Filtration efficiency was consistent for both small particulate (< 10 microns) as well as larger particulate.

    The oiled gauze filters displayed roughly the same initial filtration characteristics as the paper filters, that is to say that their filtration efficiency was relatively poor until the filter became loaded with dust. Once "loaded", the oiled gauze filters performed acceptably well in terms of filtration efficiency; their lifespan was less than oiled foam or pleated paper. Failure of the filter was much the same as oiled foam, that is to say marked by a collapse of the filtration media and a dramatic decrease in the filtration efficiency of the media. Unlike the pleated-paper and oiled-foam air filters, the oiled-gauze filters demonstrated a poor filtration ability above a certain vacuum level; the gauze is quite thin and dirt can be easily passed by the gauze under high vacuum conditions. Filtration efficiency was NOT consistent for both small particulate (< 10 microns) as well as larger particulate; the oiled gauze filters appeared to be less efficient at filtering small particulate than large, and were less efficient at small-particulate filtering than either the pleated-paper or the oiled- foam.

    Based upon the above, for a motorcycle with constant maintenance intervals, I concluded that the oiled foam filters were the best solution given dust filtration as the sole criteria. They displayed the best out-of-the-box filtration rates and these rates were uniform over the lifespan of the filter. Oiled-foam filters require more frequent servicing than oiled gauze or paper, but they filter best when just serviced; a 6K-12K service interval seems ideal for the oiled foam filters. And they are reusable, unlike pleated paper filters. Oiled gauze filters were markedly less efficient in terms of initial dust filtration, but once dirtied they filtered at a level almost equal to the oiled foam. Oiled gauze filters displayed a faster failure rate than either the oiled-foam or the pleated- paper, as well, and appeared much more sensitive to vacuum levels; the filtration efficiency of the oiled-gauze filters dropped dramatically as vacuum levels rose. As well, the split between small particulate filtration efficiency and large particulate efficiency was more pronounced in the oiled-gauze filters, with small particle efficiency suffering more than the other filter types.

    2) Now, on to airflow... Each filter is tested (usually by an "independent lab") for each OEM; the OEM will specify the vacuum levels to be used during the test and so forth. This makes a direct correlation of airflow data quite difficult. However, one fact was made quite clear by all OEM's who participated in this little exercise; airflow is directly proportional to filtration media surface area. IOW, a large paper air filter will out- flow a small oiled-gauze filter, all other things being equal. As well, the presence of an intake restriction upstream or downstream of the air filter itself in many instances makes the air filter's air flow data reasonably irrelevant. The air filter is often not the primary intake tract restriction. However, all other things being equal, an oiled-gauze filter appears to flow approx. 10-25% more CFM than an oiled-foam filter of identical surface area proportions, given a moderate intake vacuum level. The higher the vacuum level used, the smaller that gap becomes until the oiled-foam filter appears to be equivalent to the oiled-gauze in terms of absolute airflow at high vacuum. As well, filter media "loading" characteristics also have a dramatic effect on airflow. Pleated-paper filters drop in airflow rates much more than oiled-gauze or oiled-foam as the filters become dirty. Oiled-foam filters appear to be more stable across their lifespan than oiled-gauze, in terms of airflow rates. A dirty oiled-foam filter will begin to approach the airflow rates of a dirty oiled-gauze, all other things being equal. (A dirty pleated-paper filter will have a high filtration efficiency rating but will flow like a dog.)

    To speak specifically to the airflow test Dave Norton referenced above; an airflow test of new filters will be testing the pleated-paper and oiled- gauze filters when they are least restrictive as well as least-efficient in terms of actual filtration. An airflow test of used filters (6-10K mileage) would be much more realistic of a test, in that you would be testing each filter when it is running at approximately 98-99% filtration efficiency. As well, the vacuum used for the test will have a fundamental impact on the results. Certain engine designs have an inherently low intake velocity (the Honda CBX leaps to mind), while others (such as big twins and high-rpm large-displacement 4-cylinder mills) tend to have higher intake stream velocities. It would be reasonable to expect that the oiled- gauze filters would work better, from an airflow standpoint, on the CBX than an Airhead. And finally, if an individual "pod-type" air filter was used for the test, as opposed to a stock airbox and filter, the results will ALWAYS favor an oiled-gauze filter since it flows best per square inch of surface material and the surface area is limited due the small size of the air filter itself...

    My conclusions regarding airflow; who knows? This is going to have to be determined on an application-by-application basis, as the size of the air- box and the presence of upstream or downstream air flow restrictions are variables from bike to bike. The only real test I am aware of, other than to flow-bench an actual intake system (airbox and *all* intake components for *all* cylinders) for your particular machine, is to run the motorcycle briefly without an air filter to determine the power level increase without any air filter restriction. A series of timed accelerations (off-the-line and roll- on) in various gears and loads is optimal, within a specific time period of the same day and with jetting adjusted as needed during the test. If the power level increases dramatically, then the filter is a restriction and the machine may benefit from a less restrictive air filter. If the power level remains fairly constant (which most likely means less than a 5% increase in power), then the machine has intake restrictions other than the air filter and moving to a less-restrictive air filter without also addressing the rest of the intake system is pointless.

    My overall conclusions? I value filtration efficiency over maximum airflow numbers, so my first inclination is to favor the oiled-foam filter, then the pleated-paper, and last the oiled-gauze. I ran my R1100GS (closed-loop engine management system which ensured appropriate jetting) without a filter, and then with the stock pleated-paper as well as the oiled-gauze filter. Any power gains netted from running without an air filter were less than the margin of error in my timed testing; I'll call it less than 5%. Overall engine smoothness was increased above 4.5K RPM without an air filter. I concluded that the filter was a restriction in airflow above 4500RPM, but not significantly enough to provide a demonstrable decrease in power. The oiled-gauze filter displayed the same characteristics as did running with no air filter installed. I have yet to wring out the oiled-foam filter from the standpoint of engine manners and performance. Given that the "no filter" test resulted in minimum acceleration-timed power gains, I expect to be fairly comfortable with whatever the oiled-foam filter provides in terms of airflow.... Bottom line; a sheet of (thin) oiled gauze will flow more and filter less than a sheet of (thicker) oiled foam, and a paper filter is a good compromise between sturdiness and filtration requirements. Kinda a common-sense expectation and the test data does appear to support that conclusion.

    Whew! This turned out to be most of the data, minus the actual numbers and graphs.... Anyway, I hope this helps answer some folks questions regarding air filters.... As an aside, I encountered lots of OEM "fudgies" in this project. For example, K&N uses test data in their marketing literature showing a high filtration efficiency; what they don't tell you is that this data was garnered after the filter was pre-dirtied, to overcome the natural inefficiency of the oiled-gauze media to filter effectively when new. UNI provides airflow test data measured at much higher vacuum rates than the K&N test data, to overcome the fact that the oiled-gauze filter will almost always outflow an oiled-foam filter under lesser vacuum conditions. And so on... If anyone desires to pursue this issue further, I strongly recommend that the data be compared back-to-back from each filter OEM, to help weed out each filtration media's signature characteristics.
  10. Folks, I tried Pippercross got it for Rs3500 from N1 engineering,mumbai.

    What you may like

    1) Car is more drivable with low end response is seems to be like immediate,being able to drive with out waiting for turbo to assist with the speed,have been shifting gears ~1500-1600 RPM instead of 2K RPM as earlier
    2) Can ran smoother,than while it was breathing through Paper
    3) Car seems to be rev happy,I could go all the way up to 4000 RPM,earlier power used to taper off at 3200 RPM and Engine would make booming noise.
    4) Even above 3000+ RPM no substantial black smoke as it used to in Paper filter,with or with out tuning box(mild boost).

    What you may not like

    1) Oil seems to be pulled in small/minute drops to the upper layer of the foam,very small quality though,less than the size of tip of needle,I have heard compliant from cotton gauge filter of clogging the MAF sensor due to oil and dust/dirt.
    2) Whole filter finish seems to be touch low
    3) Might have to clean the filter often than Paper
    4) Fear of filter failure if it gets clogged with dirt.
    5) I got only the oil to spry , no Idea on what to use for cleaning,filter foam is not detachable like bikes air-filter foam elements.
    5) Pippercross manual says to clean it with some numbered cleaning solvent a with warm water.

    Other observations
    1) while I removed the paper filter,(which is in place since second service) saw minute dust in the airfilter air intake housing at the engine side!! so paper filter also allow dust while it is not clogged?
    2) Messed up one of the inner thread's of the three screws ,as it doesn't tighten as before,had to get some electric plastic (electrician calls it ghatta) to fix it but still not satisfied but sure it's not allowing air.
    Some one suggested me to use mseal,any suggestion welcome to fix the issue.
    3) I am told that some cars like ford escort came with Foam filter as factory default,I also heard there are some mahindra stables but not sure of the claim.
    -Sat
    Last edited by a moderator: May 29, 2011

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