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I see the different sizes as demonstrated but I think the true element surface area can only be obtained from calculating the number/depth/length of pleats of each filter. Or by removing the media from its frame and stretching/flattening it out and measuring it that way. The stock filter has too many pleats to count in this video the K&N has 25 and DNA has17. The larger physical size of the DNA may or may not be equivalent in surface area to the K&N which has 8 more shallower/shorter pleats in it.

Also I cannot fathom that either one has the same surface area as the stock one which also may filter a smaller particle size as well due to the material it appears to be made of. Maybe a better test would be to measure pressure drop across each filter in a test fixture and also take into account the particle size each is capable of trapping. ....Sorry but I am not sold.
 

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Air Flow through a Filter naturally becomes reduced as the "pores" in the filter material become "clogged" in the absence of increasing the force pushing/pulling the air through the Filter. Hence, the importance of regularly changing the Filter on a furnace to avoid excessive wear on the fan motor which must work harder as the Filter becomes increasingly contaminated.
I understand what you're saying, but allow me to expound on your example. First clogging of the filter is called "filter loading", as the filter loads up it becomes more restrictive "static resistance". A furnace fan is spinning at a set speed and pulling a specific amperage when the filter is clean. As the filter loads this imposes static resistance on the suction side of the fan decreasing air flow. Since the fan is not moving as much air the motor is actually working less and amperage drops.
Now as for an engine as the filter loads an increase in throttle opening is required to draw in the required amount of air required to produce the requested output. Since most new motors are throttle by wire, I suspect the ECU senses less load and increases the throttle opening to compensate. A motor's load is from turning the crank and everything attached to it. Since the power to rotate the crank comes from the combustion process which includes drawing in air, a dirty filter does not create work for the motor, it just requires the throttle to be opened more. I guess you could say it creates more work for the operator.
 

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...looks like some posts got zapped ...the video while it was up was more a comparison i like to see apples to apples on a test rig. Ill take a closer look at DNA when the time comes for sure!

One thing that does stand out on the DNA is how fully the available space is filled by filter media and not overly wide plastic frame. How other makers miss such an obvious opportunity is puzzling. Kudos to DNA as someone there is truly thinking.
 

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Finally changed the filter to a DNA at almost 2k miles. Taking out the OEM was a surprise. The filter media looks to be synthetic fiber and may have some light oil in it. It appears like the air is entering the filter area on a sharp angle at a high velocity and so deformed the element some.

I aligned the old filter with the box and the new filter inside. You can see from the dirt pattern that where the most flow is the box is covered and the air must come down the air tube and turn the corner. Maybe it wont make a difference? or maybe the velocity helps to whip dirt particles into the media? I don't think that filter box flows very evenly so there may be some performance to be gained in that area with a better air tube/lid . Another surprise was the finger sized holes on the air tube right next to the left fork tube. For maximum ram air it should be sealed.

I can tell the bike runs much better now with the DNA installed.
 

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Finally changed the filter to a DNA at almost 2k miles. Taking out the OEM was a surprise. The filter media looks to be synthetic fiber and may have some light oil in it. It appears like the air is entering the filter area on a sharp angle at a high velocity and so deformed the element some.

I aligned the old filter with the box and the new filter inside. You can see from the dirt pattern that where the most flow is the box is covered and the air must come down the air tube and turn the corner. Maybe it wont make a difference? or maybe the velocity helps to whip dirt particles into the media? I don't think that filter box flows very evenly so there may be some performance to be gained in that area with a better air tube/lid . Another surprise was the finger sized holes on the air tube right next to the left fork tube. For maximum ram air it should be sealed.

I can tell the bike runs much better now with the DNA installed.
Those finger size holes you refer to are there for a very good reason. Resonance.
If you go blocking them I would almost guarantee you will disrupt the air flow and do far more harm than good.
Same reason lots of cars have resonance chambers before the air flow meter.They smooth out the air flow and cut down the buffeting effect that can be caused by forcing too much air in.
Do you think a kawi engineer just drilled a shitload of holes for no good reason,or just to save weight?
There would have been a lot of flow testing behind this.
 

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Not sure I buy that its for resonance but I would buy that its a second air inlet so same effect less flow by blocking them. Its a long run into the filter box so flow will smooth out and there are no flow meters or sensors in there. Unlike a normal airbox also it is not exposed to cylinder intake pulses.

Compared to the R the front intake area is small feeding the same motor but for a few parts. The whole air tube and filter box interface seems more ruled by fit and finish than smooth flow function. That filter I took out doesn't look quite right for a highly engineered piece of kit.
 

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The holes in the tube are on the bottom? Could another reason for that is so rain water doesn't get to the filter?

After seeing the surprising performance gains of the DNA filter, that's what I installed as well.
The manual says the filter is "a wet paper filter". Here's mine after 4000 miles :
 

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the holes are on the inside of the air tube facing the left fork tube. Put your hand down there you'll feel them. There are drain tubes in the bottom of the filter box.
 

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The uneven dirt and wear tell a story. I am one of few outside F1 who has inspected an intake duct from a vehicle where every performance angle is exploited. Do you really think the flow not is pre staged? Swirl is important. The air entering our engines has to traverse a near right angle. The compromise is style and for bits not to stick out the side of the bike!
 

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Interesting that Kawiguy454s filter & mine have an almost identical trapped dust/dirt pattern, see that dirty 3/4 circle? I imagine that's where the strongest suction action is from the circular impeller and it's more towards the rear because of how the air is rammed in there.

Kawiguy454:


Mine :
 

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^^^ ...I noticed that too. And what I try to get across in the picture is that the dirty area of the filter is what is behind the plastic cover and not in alignment with the air tube.

So if you look down from above and visualize the incoming airflow it makes a ~90 degree left turn to the filter box then a ~90 degree right turn to the filter where you see the dirt. Where the dirt is embedded is sort of a backwards "C" pattern. I would be happier if I saw a nice even oval pattern there. Turns without smooth radii are not usually good for airflow.

H2rcx, I worked in and around automotive (Ford) design and engineering center for 12 years before moving to aerospace. The fit and finish guys would take fantastic functional designs and break them in order to look a certain way or save 2 pennies. And yes also so the functional bits don't hit you in the leg. :)

So the engine guys make this awesome SC'd powerplant then hand it over to a designer packager that is good at packaging a path with cross sectional constraints but not so good at aero. It looks good for sure and does work ...but maybe there's room to improve is all I'm saying especially for modders. Maybe someone will create some clever plastic replacement tube for us to bolt on.
 
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To improve on path you would need to have a much straighter tube running to the S/C without the 90 deg bend at the end.
Unfortunately that is not possible without making the bike 2 feet wider.
The way the filter is dirtying in the same area is due to the air being bounced (so to speak) from the end of the intake tube and then volleyed back in the opposite direction from the filter housing,like you explained with the 90 degree turns above.
I think it's actually quite smart to do it this way and take the crap away from the weakest part of the filter which would be the middle of it and line it up with the S/C intake.
An aftermarket cleanable filter is a must for our bikes I think.DNA or K & N.
 
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