Originally Posted by Kev (Post 101968)

Do yourself a favour get a DNA stage1 filter, the DNA stage 1 filter flows more air then a K&N stage 1 filter.

The results are very impressive and enlightening.
All the air flow tests took place the same day on DNA�s Rotronics Computerized FlowBench, the test pressure was 1,5� inches of water and the results corrected to 25� celcius.
1.Presentation of the air filters:

a) Stock Yamaha air filter, single layer paper non-reusable air filter
b) K&N YA-6604 air filter, 4 layer cotton oil impregnated reusable air filter
c) DNA P-Y6E04-01 air filter, 4 layer cotton oil impregnated reusable air filter

2.Air Filter Design (see attached files)

a) The K&N YA-6604 air filter:
Media material 4 layers of K&N cotton
Number of pleats 11
Pleat Height 21 mm
Active Pleat length 115mm*
Pleat Pitch 6,36mm*
Oil volume 7ml
Total active filtering surface 53.130�mm*
� * as measured from the K&N sample filter we purchased.

b) The DNA P-Y6E04-01 air filter:
Media material 4 layers of DNA cotton
Number of pleats 9
Pleat Height 31 mm
Active Pleat length 124mm
Pleat Pitch 10mm
Oil volume 16,3ml
Total active filtering surface 69.192�mm

As we can see the DNA filter has larger pleat height 31mm(K&N 21mm), the pleat pitch is 10mm(K&N 6.36mm), the amount of oil DNA uses is more than double, and the most important +30.23% more active filtering surface..! for the same application.

At this point I must explain that the pitch of the DNA material is calculated taking under consideration many different variables; we use a specially developed algorithm and the final design varies from application to application. Even 0.1 of a mm can make a very big difference in airflow, speed of the air stream at the surface of the filter, turbulence and many more details that we can�t mention for obvious reasons.

So already from the start we have2 very different air filters!

Let�s continue with the tests.

3. Absolute AIR FLOW tests: the filters are tested out of the air box on a custom made plenum; nothing causes turbulence or restrictions to the air flow
(see attachments).
The result is solely what the filter can give.

a) Stock Yamaha Paper Air filter
70.42 CFM @ 1.5� of H�O

b) K&N YA-6604
92.18 CFM @ 1.5� of H�O
+30.9% over stock

c) DNA P-Y6E04-01
122.4 CFM @ 1.5� of H�O
+73.81% over stock
+32.78% over K&N�?

4. Air Box AIR FLOW tests: the filters are tested inside the stock Yamaha air box,
To eliminate the losses (restriction) that the stock throttle body could cause we used a 48.6mm throttle body without the butterfly; the absolute largest that could be connected to the XT 660 Rubber trumpet.
Air box restrictions, shape, resonance, position of the air filter, if the design of the air filter suits the design of the air box and many more variables play an important role now.
Also I have added the Volumetric Efficiency (VE), of the XT 660 Engine, that occurs for every configuration, if the tuner takes 100% advantage of the extra flow.

a)Test 1:
Air box & std filter & snorkel
46.53 CFM (1318 lit/min) VE=0.539

b)Test 2:
Air box & K&N filter & snorkel
52.51 CFM (1486 lit/min) VE=0.608

c)Test 3:
Air box & DNA filter & snorkel
57.19 CFM (1619 lit/min) VE=0.663

d)Test 4:
Air box & DNA filter & Without snorkel
59.52 CFM (1685 lit/min) VE=0.690

e)Test 5:
Air box & DNA filter & DNA Stage 2 filter & snorkel
79.19 CFM (2242 lit/min) VE=0.918

f)Test 6:
Air box & DNA filter & DNA Stage 2 filter Without snorkel
79.89 CFM (2262 lit/min) VE=0.926

g)Test 7:
Air box all open Without filters, side cover, snorkel
(this test is for reference only the bike can�t be used on the road in this state)
88.6 CFM (2509 lit/min) VE=1.027

Finishing our detailed tests clearly the conclusion is That the DNA stage 1 filter is NOT the same filter as the K&N as the overall difference is Massive.