The XT660X/R Air Box & Filters
 

There still seems to be a bit of confusion over the XT's air box. I have done a complete explanation on the air box, filters & how it all works.

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The Yamaha air box is not really good for air flow. I am sure you can now see why you get good gains when fitting a DNA Stage 2 air box side filter in place of the Yamaha side cover. The stage 2 filter can supply air directly to the throttle body with no restriction.

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You can only just see the main filter from the throttle body side, not good for flow.

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You can now see why the DNA stage 3 Air box works so well with no restrictions with positive air flow & volume.

http://i201.photobucket.com/albums/a...xtx/2-31-1.jpg

Alot of riders are worried about removing the snorkel. I would recommend you to fit a stage 1 DNA air filter, these filters are oil based & repel water. Looking from the removed snorkel you can see the water drain hole into the air boxes 3rd chamber.

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Finally the flow tests for the filters.

Hi Guys,
Following your request I have finally put together a presentation of the DNA P-Y6E04-01 Stage 1 filter compared back to back with the K&N YA-6604 Stage 1 filter, and more useful information that will help you tune the XT 660 R /X.

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.


Also you can see why the fueling must be adjusted when going stage 2 and why you can get away with it, when removing only the snorkel.

I would like to thank to all the forum members for their attention, I hope everyone will enjoy the above info.

The Stage 3 DNA Air Box is the best by far.

• Extreme air flow 111,9 CFM @ 1,5 Inches of water
• + 40% more than the popular DNA Stage 2 application!
• + 140,49% more than the stock air box & filter!
• 98-99% filtering efficiency for maximum engine protection
• Unique DNA air filter with built in venturi designed to smoothen out the air flow
• Dyno proven +8 HP more power from the standard engine (with Powercommander or Race slip on’s)
• Dyno proven +14 HP more power from a highly modified 700cc engine
• Specially designed rubber velocity stack, increases and spreads torque over a wider rpm range, with the possibility to alter the tuned length for custom applications
• All standard parts bolt on or attach to the S3 Air box (Battery, ECU, Rectifier, Temperature sensor, Idle circuit, AIS circuit, Crank case vent, Rear wheel mud flap)
• Specially designed aluminium adapter that can be modified to adapt big bore throttle bodies
• Designed to be used in rainy weather (Att. Not to be completely submerged in water)
• Unique design of side covers & frame allows unrestricted air flow and catches the eye!
• Shipped ready to install, includes installation info, 2 Powercommander Maps, dyno Graphs, and air flow Graphs
• Limited production unit with individual Serial Number.

COR what a difference. Ordered a K&N filter, took the snorkel out and wallop, gutsy sound with standard pipes, loads more low down stomp and generally smoother and easier to ride

A great helpful thread, thanks guys! :notworthy[1]:

Tempted to do more now, but thinking that much more noise will be a pain around town

Hi Kev,
I believe the above is what you are looking for.
If you need more info please let me know.
Best regards,

Dino

Thanks Dino this is what I was looking for. I seemed to deleted the link from the mod section, have since found the comparison testing between the DNA & K&N filters.

http://www.xt660.com/showthread.php?t=9848

Help please with very poor running.
 

Hello Kev,
I have an 08 660x with scorpion cans runs like an on /off switch but at least a bit of acceleration now standard pipes are gone.Some questions please,does the snorkel just unbolt and if i take this off put in a dna filter and plug in a NITRO FUEL COMMANDER [can't afford a PC III or V] IF i do these mods will it run better and will i need an O2 eliminator,please advise because if i can't get it to run better it will have to go,i WANT to keep it but it runs terrible standard surges real bad,Thanks alot for any advice.gaz

The snorkel just pulls out,spray in WD and pull!!,I run mine with Kev's fuel mod,K+N 1 and DNA2 and no 02 eliminator, the bike runs fine.

All this info is on the site anyway,as I had pointed out too me on another site the search button is your friend http://www.xt660.com/images/icons/icon7.gif

Sorry to be a pain, I was wondering where to drill the extra holes in the standard airbox with the snorkel removed?? Not on the side cover as that is the filtered side, so around the snorkel "hole" I guess??? Thanks thanks thanks

All the info is in the mod book you bought yesterday, page 284 in the XTX & XTR mod section. To answer your question the extra holes are drilled in the snorkel chamber.

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