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Message started by DragBikeMike on 11/30/18 at 09:49:49

Title: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:49:49

This is a long post with lots of pictures. Please hold off on comments until I make the final entry. I will make it evident when I have made the final entry.

This is a test of the three air filter elements currently available for the LS650 airbox. As far as I know, the only elements available are the stock Suzuki element, the K&N element, and a hybrid element constructed from the stock element frame filled with a product called Polyi-fil Nu Foam. The poly-fil product is manufactured by Fairfield industries in Danbury, CT.

I had the original OEM filter from my 2016 LS650. It has about 1000 miles on it and is pretty much in new condition. I removed the K&N element from my bike, so I could use it for the test. It has about 1200 miles on it and is also in new condition. I purchased the Poly-fil Nu Foam from Amazon. I made sure to get the exact product spelled out in other posts on this forum. It comes in 16” x 16” x 1” thick sheets. It is described as “densified polyester”, part/product number DB1612, and costs about $20 for a 2 pack. You can make a lot of filters with a 2 pack.

The stock filter is on the left, K&N in the middle, and the poly-fil material on the right.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:51:20

After I removed my K&N, I took a swipe on the downstream side of my airbox to check how well the K&N was cleaning things up.

Looks like the K&N is doing a good job. There was virtually no sign of any sort of dirt.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:54:11

The stock filter is intended to run dry. The K&N is an oiled gauze filter and the element I tested had the as-delivered oil charge. The poly-fil element is supposed to be oiled with Mazola canola oil spray. I couldn’t find Mazola, so I used another product that is 100% canola oil. I also tested the poly-fil using K&N filter oil to see if it made any difference since it’s an oil specifically intended for air filters.

Never heard of Gold Emblem but id does say 100% canola oil. Can’t get any more canola than that.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:55:20

Here we have the standard K&N filter oil. I would have preferred the aerosol spray, but the speed shop only had this. I applied it with a brush and it seemed to cover and penetrate OK.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:57:36

I performed the tests using my budget flow bench. I knew the flow bench would have a very hard time keeping up with air filter elements. The filter elements are intended to flow big numbers and offer almost no restriction. I was hoping I could achieve a test pressure of 5” H2O so that I could use the conversion tables to convert to 15” H2O, which would give us an idea of the actual flow in CFM. As it turned out, 5” H2O was way too ambitious. No way I could pull that sort of depression with my little bench.

The stock element and the K&N element were simple to mount on the flow bench. I made a base frame of the correct dimensions and attached/sealed it to the top flange of the bench with latex calking. Then I placed the element under test onto the base frame and tied it down to make a good seal. For the poly-fil material, I made a mock filter frame with a screen bottom (just like the stock frame). The opening in the mock frame is the same size as the opening in the stock frame.

This is the test fixture assembly. It mounts on the flow bench and the filter assemblies are placed on the fixture.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 09:59:08

This is the mock frame for the poly-fil material. It has a screen across the bottom just like the stock frame. The screen is sealed to the wood with clear latex calking.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:00:16

The bottom of the frame has foam sealing tape applied to help make the seal between the frame and test fixture. This photo shows a chunk of the poly-fil installed in the frame.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:01:24

This photo shows the stock element installed on the rig. It’s held down by a screw on one side, and a zip tie with small clamp on the other.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:02:17

This shows the K&N element installed on the test fixture. It’s held down by nylon cord. It should be noted that none of the elements really needed to be held down. They all have some sort of soft, compliant sealing mechanism incorporated in the base, and once you fire up the vacuum they pretty much seal on their own, but I wanted to be sure the joints were tight with no leakage.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:03:25

This shows the poly-fil frame installed on the test fixture.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:04:56

The poly-fil would be tested dry, with canola oil, and with K&N oil. I oiled up two poly-fil inserts 24 hours before the test and let them sit so that the oil had time to disperse through the filter.

This is how the canola oil appeared before testing. Oil was only applied to the top and sides of the filter. The bottom was left dry.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:05:45

As you can see, the underside was dry.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:06:47

Same process for the K&N oil, except I had to brush it on. Bottom side was also left dry.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:08:29

I started the test using a 51.85mm orifice which is rated 209 CFM @ 15” H2O. As I said, I was hoping I would have at least enough restriction to test @ 5” H2O and then convert the data. I wasn’t able to achieve 5” H20 test pressure. There just isn’t enough restriction. So, I started trying to test at the maximum depression I could achieve. At first, that seemed to be working OK, but then I started having trouble with repeatability. As the day wore on, and the temperature, humidity, and barometric pressure changed, the test results changed. I was frustrated, so I sat down and thought things out.

The main reason I built this contraption was to be able to test components on a level playing field. Always test at the same pressure from one test piece to another. Then it dawned on me, find out which element had the lowest depression at full flow, and then test each filter at that pressure. If you have to apply a higher test pressure to achieve the same flow, the filter under test obviously doesn’t perform as well. Note that on this test, when I use the term “test pressure”, it refers to a negative value (vacuum).

So, I started over. I tested each filter with all bleed valves closed to find out which one resulted in the smallest test pressure. I did baseline runs using the 51.85mm orifice on all the filter elements to determine which element resulted in the lowest pressure. Then I did a single run using a 42.38mm orifice on the best performing element. I felt that two sets of data would allow cross checks to make sure things made sense. The K&N pulled the smallest test pressure, so it was already evident which element performs best. But I wanted to practice and learn, so I continued with the full test.

Full Pull Test Pressures (51.85mm orifice, all bleeds closed)

Stock: 1-7/8” H2O
K&N: 1” H2O
Poly-fil dry: 2” H2O
Poly-fil canola oil: 2-3/4” H2O
Pol-fil K&N oil: 2-1/2” H2O

Full Pull Test Pressures (42.38mm orifice, all bleeds closed)

K&N: ¾” H2O

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:17:23

Time to start the real testing. With the 51.85mm orifice, each element was tested @ 1” H2O. With the 42.38mm orifice, each element was tested @ ¾” H2O. Under these conditions, we get readouts in percent off the inclined scale. That allows a good comparison from one element to the other.

Test with 51.85mm orifice @ 1” H2O

Stock: 45%
K&N: 70%
Poly-fil dry: 45%
Poly-fil canola oil: 36%
Poly-fil K&N oil: 38%

Test with 42.38mm orifice @ ¾” H2O

Stock: 58%
K&N: 98%
Poly-fil dry: 57%
Poly-fil canola oil: 47%
Poly-fil K&N oil: 50%

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:19:17

Don’t let the percentage value confuse things. That value represents the percentage of rated flow for a particular orifice @ 15” H2O. I couldn’t achieve anywhere near 15” H2O because these elements don’t offer enough restriction to start pulling higher vacuums with this small vacuum source. The shop vac just isn’t big enough to torture these filters. But at the test pressures used, the percentages give us a very good picture of which elements perform better. I think it’s safe to say that the K&N outperforms all other elements by a comfortable margin. It also looks like the K&N filter oil performs a little better than canola.

It’s hard to say whether the other filter elements would come closer to the K&N as the flow went up. The data seems to trend in that direction. The spread is smaller @ 1” H2O than it is @ ¾”, but I’m almost certain the two curves will never cross.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:26:05

Now we have some hard data to help choose the best filter element for the intended application.

If you are looking for a no hassle replacement that you know will fit and work as intended, the OEM filter is probably a good bet. It costs $30 and you only have to replace it every 7500 miles. It flows as intended, and you can rest comfortably knowing your engine’s health is in good hands.

The poly-fil takes some effort, but its bargain basement price makes it the economy king. With 512 square inches of material for $20, and an additional $3 for canola oil, you can fabricate at least 18 elements. That works out to about $1.25 a copy. Others have tested its effectiveness at keeping dirt out of your engine, and it appears to do that just fine. I was expecting it to flow better than the stock filter since some have reported improved performance with this material. I did my level best to procure the exact material previously posted. It may be that Fairfield has changed the composition of the poly-fil nu-foam, possibly some improvement geared toward its intended use (furniture cushions). It also might be that I didn’t get the right stuff. If any of you can confirm if the stuff I tested is right or wrong it would be most helpful.

The K&N is the Cadillac of filtration devices, and its entry price of $54 justifies the Cadillac moniker. It costs a fortune, but it’s the airflow champ. It fits correctly and has a good reputation for keeping the dirt out. It also lasts the life of the motorcycle, so it’s a one-time investment.

Here is a picture of the poly-fil package. As I mentioned, its possible that I may have procured the wrong product. If any of you can confirm whether or not its the correct stuff, please let us all know.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 10:28:30

While researching filter prices, I stumbled across another choice, the HiFlo Filtro. It retails for $15, looks like a standard paper element, and seems to have some good reviews. If I can get my hands on one, I will test it and post the results.

On 04/09/18 I posted some test results on various modifications to the airbox (see “Air Box Performance Tests”). Those tests were performed with a simple u-tube manometer. I intend to retest the airbox mods using the flow bench. That way, we might be able to get some data that reflects actual flow, rather than simply a change in flow.

Hope this information is useful to you all. Knowledge is power.

Best regards, Mike

Title: Re: Air Filter Flow Test
Post by ohiomoto on 11/30/18 at 11:21:05

I could have sent you an airbox for this test. :)

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 11/30/18 at 22:56:16

Thanks Ohiomoto, but the airbox has to stay in the bike for the tests. The seat actually forms part of the flow path into the snorkel. I'm also finding that the decorative covers that hide the airbox make a significant difference. More to come.

Title: Re: Air Filter Flow Test
Post by batman on 12/01/18 at 09:17:46

I 'm more concerned with the primary purpose of an air filter ,that is to say filtering out the crud and prolonging the life of my motor, than I am how a filter might add to the motor's performance.
The stock air filter does a very good job of filtering , but the paper being pleated (the bends being compressed) does restrict flow.
The K&N filter has higher flow when compared to polyester , but this may be due to thickness of the material .
The real difference is the filter material , K&N uses cotton ,which in my mind comes up a bit short on performance. Cotton being a textile fabric is hydroscopic ,that is it absorbs moisture quickly, and dries rather slowly. It has a normal moisture content of 8% right out of the box. When exposed to moisture for prolonged periods ( your riding season/changes in relative humidity) it may cause dimensional changes in texture and shape, and this is not fully reversible .( the moisture level does not return to 8% but is somewhat higher afterward ). This may be a factor in DBM's testing where the results were unrepeatable. Moisture contained in the cotton may have swelled the fibers restricting flow ,degrading performance of a K&N filter over time.
Filters made of polyester fibers (0.4% moisture ) are hydrophobic , they absorb no water ,so are dimensionally stable. where it is true that the Oldfeller's home cooked filter does not flow as well as the K&N , more importantly it's performance( filtering) remains consistent over time. Simply washing the K&N "s cotton may degrade it's performance ,polyester could care less. I haven't heard how often the K&N has to be cleaned and reoiled(nor the cost of said oil?) ,but my Oldfeller's filters on my bike only need cleaning every other season (2 years-7,000 miles).
If I was involved in a racing situation I might consider a K&N filter,with frequent changes, but for piece of mind ,low cost ,low maintenance,I wont.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/01/18 at 14:27:35

Regarding consistency of the data, I had problems with consistency because I was performing the tests using the floating pressure drop method (i.e. just closing all the bleeds and seeing which combination resulted in the lowest depression). That method will tell you which combination offers the least resistance to flow, but the results are significantly affected by atmospheric conditions, and you can’t readily convert the results to a flow. You know its more or less, but you don’t know how much. I’d go to recheck a combination and the result would be different. So, as I said earlier in the post, I sat down and thought things out. I changed my method to the standard pressure drop, where you do all the tests at a fixed pressure. Once I started testing all combinations at the same pressure, the results were totally repeatable. I could come back to the rig the next day under slightly different atmospheric conditions and get the same results. My inconsistent data was the result of my method, not the filter absorbing water. The inconsistencies were across the board, stock, poly-fil, K&N, I would get screwy data on all of the combos.

Regarding the pleats, those pleats expand the surface area of the filter media so that the area exposed to the flow of air is actually about 2-1/2 times greater than the filter frame. So that would make the stock pleated filter about 2-1/2 times larger (in area exposed to flow) than the poly-fil inserted into the stock frame. The opening in the frame is 4.75 x 4.31 for an area of 20.5 inches squared. If you take the pleated media out of the frame and lay it out flat, it measures 4.75 x 17.25 for an area of 53.4 inches squared.

There are 14 pleats in the stock filter, and each pleat is 5/8” tall. I used a long strip of paper 4.75” and folded it to form 14 pleats that were 5/8”. I made sure it fit correctly in the test frame. When stretched out and laid flat it measures 17-1/4”. That works out to a lot more exposed surface.

Here is a shot of the paper mockup.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/01/18 at 14:28:34

Here's a shot of the paper mockup stretched out and laid flat.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/01/18 at 14:33:07

I’m not sure what affect humidity in the air has on the K&N. I do know the poly-fil package talks to the fact that the polyester material doesn’t absorb water. The K&N gauze filter is saturated with oil. I don’t see there being a lot of room for moisture to get into the fabric with all that oil. I do know that K&N has an excellent reputation, and until now, I’ve never heard any complaints about the hydroscopic properties of the filter media used in the K&N.

I'm looking for performance. Some of you are looking for economy. Some want simplicity and ease of maintenance. This study should provide some good data to help you make an informed choice.

Title: Re: Air Filter Flow Test
Post by batman on 12/01/18 at 17:11:28

Well Mike I suppose we could debate things all day, but there is 27 bends in the paper stock filter and rather closely spaced ,each bend doubling the thickness of the paper and the air has to change direction twice as it passes threw. So my question is how much effective surface area does the filter have ? It doesn't lie flat in the frame ,so measuring it in the open position doesn't impress me much.
K&N claims the filter will last the life of the bike, my bike is 23 years old ,yet I own no 23 year old cotton T shirts that I've worn 6 months a year. Your testing K&N filter with 1200 miles , Check it again at 10,000 or 20,000 miles and if it's still in good shape I may but one. You would think that a filter that costs $50+ dollars might contain polyester filtering material rather than cheap cotton. Just my take.

Title: Re: Air Filter Flow Test
Post by eau de sauvage on 12/01/18 at 18:14:21

I bought a k & n and had to send it back because it does not fit. The top of the filter hits the backward sloping surface at the top of the airbox which pushes the filter away from where it is meant to seal.

I had numerous emails with all different people at K & N where they kept asking for more information then not replying back. FFIW the entire company are a bunch of deceptive lying scumbags. I'll post some photos if you like.

I have also discovered upon checking my old OEM filter that the pleats have a lot of sand in them even though it's just used on the road. How that sand gets in there is hard to see seeing how the intake is so protected, but you wouldn't want any of that in your engine.

I bought some special foam and the correct oil but I've not yet worked out the best way to fit it into the old gutted filter.

edit: see for yourself...

http://https://i.postimg.cc/Vr9w8P9v/comparison-size.jpg (https://postimg.cc/Vr9w8P9v)

http://https://i.postimg.cc/zbwyPMVS/doesn-t-fit.jpg (https://postimg.cc/zbwyPMVS)

http://https://i.postimg.cc/gXyKqgp1/OEM-fit.jpg (https://postimg.cc/gXyKqgp1)

http://https://i.postimg.cc/sQY6XVNF/bends-back.jpg (https://postimg.cc/sQY6XVNF)

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/01/18 at 21:10:09

Eau de Sauvage, I appreciate you sharing those photos and your experience with the K&N product. All I can say is my K&N fits perfectly, and the swipes I took indicate that zero dirt is getting past that filter. I've been using K&N products for many years and have never had the need to request assistance from the manufacturer. They've always fit perfectly and performed as advertised. But I have to admit, if you get a turkey, you want the manufacturer to stand behind their product and make good on it.

This post isn't an advertisement for K&N. I'm just trying to gather data on what's available and share with everyone else. So far, using methods that I think are unbiased and technically sound, my data shows the K&N flows best. Pleats or not, you can't argue with the data. The K&N flows best. I haven't come up with a way to test the filtering properties of the media. Old Fellers swipe method seemed reasonable to me. The maintenance issues are sort of a personal preference. Some folks might find messing around washing and re-oiling filters humbug. I personally enjoy stuff like that, and I imagine Batman enjoys it too. The stocker is the maintenance king, take out the old one, shove in a new one. Cost is certainly a concern and the K&N loses that contest hands down.

The data obtained for this filter test correlates nicely with the airbox tests that I am currently doing. So, in a few days, I will be finished with the airbox and post that information. As it turns out, with the right mods, you can get the stock element to flow fairly well, you just have to be willing to accept a lot of intake noise.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/01/18 at 21:20:47

BTW, Batz, I ran a K&N in my old Harley. I bought the bike new in 1990 and almost immediately installed an S&S Super E carb. That carburetor kit came with a foam filter element that was pretty sketchy so again, almost immediately, I changed out that element with a K&N. I rode that bike for 16 years, then I hung it up. Sold it in 2015. Still had the same K&N element. The guy that bought it from me had me do some work on it about six months ago. It still has the same K&N element, and it looks just fine, and there isn't a pile of dirt clinging to the mouth of the carburetor so I assume its still trapping the crud. What can I say, that cheap cotton, you know it only lasts about 28 years. I might also add, that in the 25 years I owned it, I don't remember ever even washing and reoiling it. But I'm really old and tend to forget stuff like that. Heck, I must have serviced it at least once or twice in 25 years.

Title: Re: Air Filter Flow Test
Post by batman on 12/01/18 at 22:01:47

Well I have friends with Harleys and I am familiar with the filter that comes with those S&S carbs, and you can hardly do worse, that very thin open foam is completely worthless, but if you didn't oil the K&N, I can't believe it didn't pass a lot of fine particles into the motor, perhaps your lucky.

Title: Re: Air Filter Flow Test
Post by justin_o_guy2 on 12/01/18 at 23:05:47

Of all the money I spent on mine, I only regretted the K&N air filter.I wouldn't do that again.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/02/18 at 20:30:38

Thanks for chiming in JOG. Can you share with us the details on why you were dissatisfied with the K&N?

Title: Re: Air Filter Flow Test
Post by justin_o_guy2 on 12/02/18 at 22:19:03

Didn't fit the airbox.
Once I modified the box, okay.
It didn't create any
Seat of the Pants dynamometer
horsepower.
When it was time to clean it,
Unless you have a replacement filter
You're parked until it's ready.

I see it as a religious ritual in search of a moment,, and it's not worth it.

Title: Re: Air Filter Flow Test
Post by eau de sauvage on 12/02/18 at 22:58:22

61676814161115250 wrote:

snip

Yes, the main issue I had with K & N was that in face of incontrovertible evidence, I mean you can see side by side it's oversized, nevertheless all they did was keep handing off to another person who asked for more details and never responded again, happened three times.

When I brought this up way back when, it seems it's not a one off, some people said like you it fit fine, yet there were others who said they had to build up the airbox with filler to make it fit but they didn't have a problem with that.

However I'd be interested to know if you have tested the correct filter foam with the correct oil for these filters. Because I have an OEM filter case gutted, but it seems that to do it right will need a bit of welding and I'd be more enthusiastic about it if it was tested and proved to be better.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 12/03/18 at 12:23:13

JOG, I love the "Religious Ritual" comment. I agree that washing and re-oiling filters is pretty much a pain. I'm always searching for that last little pit of go-power so I guess you could say I'm the religious type. The stock filter sure is easy to R&R.

Eau de sauvage, while I was doing additional tests on the airbox over the weekend, I had the opportunity to peer down the throat of the airbox (with the snorkel removed) at the fitup on the left side of the filter. I noted there is a hook fit along that left side, and the square edge of the filter element has to slip under that hook. When I misaligned the K&N with the hook, such that the edge of the filter butted against the edge of the hook rather than slip under it, the filter fit exactly like the photos you attached to your post. It is significantly more difficult to slip the K&N into place than it is to slip the stock filter into place. The stock filter has a taper on the left edge that, looks to me, like its intended to allow the user to install the element at an angle, slip the edge under the hook fit, and then pivot the filter forward and into place. The K&N doesn't incorporate the tapered edge, which makes it more difficult to slip under the hook.

Regardless of the reason for your fitup problem, if you weren't satisfied with that filter, K&N should have taken care of you. Did they refund your money, send you another element, do anything to make you happy, or just blow you off?

I don't understand your question regarding "correct filter foam with correct oil". I tested the stock filter (pleated fabric/paper, no oil specified), the K&N (pleated gauze with K&N specified oil), and a homebrew assembly (stock frame with a polyester filler material oiled with canola oil). For the homebrew assembly, I made a wood frame to simulate the stock steel frame. I didn't test any sort of foam filter.

If you are interested in improved performance, and don't want to mess around with cleaning and oiling filters, you can realize significant improvements in flow with some simple (and free) modifications to your airbox. There's a lot more flow available with the stock element. Take a look at the latest entries to my post "Airbox Performance Tests", posted yesterday.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:29:12

Lancer was kind enough to loan me a Uni Filter pod to test. It’s a foam pod that clamps directly to the inlet of the carburetor. There is an outer sock intended to be used in heavy dust conditions.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:30:09

The filter must be oiled in order for it to work properly. Uni even includes a warning that serious engine damage will occur if the filter is not oiled.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:30:52

So I rounded up some official Uni Filter Oil. It cost about 13 bucks and should last a very long time.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:31:38

Because the configuration of the pod filter is different, I fabricated a special fitting to mount the pod to the flow bench. To give the pod a fair test, I tried to make sure that the flow path into the bench was as large and smooth as possible. To do this, I bored the ID of the fitting to eliminate any bottle-necks. I also turned down the OD to accept the Uni 2.5” socket.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:32:29

The adapter fitting and filter fit the test bench perfectly.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:36:03

I started by doing a cross check with the stock filter element to verify that the bench would provide consistent results. With the 51.85mm orifice, the stock element flowed 45% @ 1" H2O, exactly the same as the original test at the beginning of December. The bench looks like its working fine.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:38:45

I performed tests with the foam element dry, and then oiled it in accordance with the instructions for the Uni Filter oil.

Test results with the filter dry, 51.85mm orifice @ 1” H2O

Outer sock installed 30%
Outer sock removed 32%

Test results with the filter oiled, 51.85mm orifice @ 1” H2O

Outer sock installed 30%
Outer sock removed 32%

Test results with the filter dry, 42.38mm orifice @ 3/4” H2O

Outer sock installed 38%
Outer sock removed 40%

Test results with the filter oiled, 42.38mm orifice @ 3/4” H2O

Outer sock installed 38%
Outer sock removed 40%

Its evident that the Uni oil does not restrict flow. It’s a messy job to oil up the filter element but is well worth the effort. The oil doesn’t affect the flow and is required to allow the filter to perform as intended.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:40:08

So now we have a sixth configuration to compare to the five I previously tested. I assumed we all would elect to run the Uni Filter without the sock since these aren’t dirt bikes. Here’s how things shook out with the Uni in the mix configured for street use in accordance with instructions and warnings.

Test with 51.85mm orifice @ 1” H2O

Stock: 45%
K&N: 70%
Poly-fil dry: 45%
Poly-fil canola oil: 36%
Poly-fil K&N oil: 38%
Uni Filter: 32%

Test with 42.38mm orifice @ ¾” H2O

Stock: 58%
K&N: 98%
Poly-fil dry: 57%
Poly-fil canola oil: 47%
Poly-fil K&N oil: 50%
Uni Filter: 40%

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/08/19 at 14:46:50

This data paints a poor picture of the Uni. It looks to be very restrictive. But there is another item to consider. The Uni doesn’t utilize an air box. The Uni replaces the air box. So, I tried to test the Uni at 5” H2O like I did on my air box tests. The pod doesn’t restrict flow enough to achieve 5” H2O on my little bench. The best I could pull was 4-1/4” H2O. That rivals the K&N filter in a Max Modified air box. If you want to know more about the air box mods and tests, see my post titled "Air Box Performance Tests", last entry dated 12/2/18. Here’s how things shook out at 4-1/4” H2O.

Oiled Uni Filter (no sock) @ 4-1/4” H2O, 51.84mm orifice: 64%

K&N filter in Max Modified air box @ 4-1/4” H2O: 62%

Looks like the Uni pod filter gets the job done. Since it essentially eliminates the air box it becomes the best flowing setup tested so far. Of course, there are other considerations that come into the picture. The Uni will be loud, and there’s the issue of intake tuning, air box volume, weather protection, stuff like that. But if you are simply looking for high flow and easy maintenance, the Uni looks pretty good.

Title: Re: Air Filter Flow Test
Post by LANCER on 01/09/19 at 07:43:44

This was not part of the test but an additional advantage to the Uni is the price, almost 1/3 the cost of a K&N and they are easier to install in the confined space we have to deal with.

Title: Re: Air Filter Flow Test
Post by Dave on 01/09/19 at 09:20:15

The Uni was my filter of choice for my Cafe' build....although I used a version slightly larger than the one you tested. It is definitely louder than the stock setup - but so is my muffler.

http://i50.tinypic.com/fxw3up.jpg

Title: Re: Air Filter Flow Test
Post by verslagen1 on 01/09/19 at 09:59:04

Any plans to test efficiency?

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/10/19 at 15:01:34

At this point, I don't have a setup to test how well an element traps dirt. I did take swipes on the interior of my airbox (downstream of the element). The K&N wasn't letting any dirt get past. With the Uni Pod, I would have to either remove the airbox and run it for a thousand miles or so, then take swipes on the interior of the carburetor, or set up some sort of dust generator. I'm not planning to do that since I intend to keep the airbox, primarily for noise reduction, but I also feel it's a good setup that provides a plenum for air storage and also a longer intake tract from the inlet valves to the end of the hose connection at the airbox. So, we must resort to asking the current users of the Uni Pod to comment on how well it keeps the crud out. Lancer & Dave, how well does your Uni trap dirt?

At this point, I guess what I should do is see if I can get a little more out of the modified airbox. I have some ideas but am concerned about noise. Mine is currently pretty quiet so I guess I could live with a bit more racket. I just can't sit by and let the Uni Pod garner all the glory.

Title: Re: Air Filter Flow Test
Post by Dave on 01/10/19 at 15:09:30

I have to believe that the oiled foam filters trap dirt really well. Every dirt bike I ever owned used an oiled foam filter.....and I have ridden in horribly dusty conditions, and never had any excessive wear.

The 250 Ninja also has an oiled foam filter.....from the factory.

It is not surprising that the UNI flows well. The oil doesn't block the air passages and trap the dirt the same way a paper filter does - but as the air winds it's way through the twists and curves in the foam, the dirt bumps into the surface of the passages and gets trapped in the oily surfaces. Eventually the dirt covers the oily surfaces....and the filter needs to be washed and re-oiled to remain effective.

Title: Re: Air Filter Flow Test
Post by DragBikeMike on 01/10/19 at 21:37:04

Dave, I have to agree with your assumption based on dirt bike application, but have you ever inspected your carburetor inlet when you removed the pod filter, or taken swipes to check on how well it functions? That would provide some concrete evidence that it does its job. I'm sure it works well but some sort of definitive evidence would be good to corroborate the assumption.