www.CVOHARLEY.com
CVO Social => In The News => Topic started by: CVOJOE on June 21, 2006, 11:24:38 PM
-
Pretty comprehensive testing article in August American Rider magazine. Testing was conducted by K&N and here's a summary of their results:
MODEL PRICE CFM % CHANGE
HD Stock N/A 171.2 BASELINE
Zipper's 117-296 $62 320.8 87.4%
Cycle Smith $375 303.5 77.3%
K&N RK-3909 $160 300.1 75.3%
Scrm Eagle 29773-02B $139 287.7 68.0%
Drag Spec/Doherty 1240 $198 287.0 67.7%
Kuryakyn 9804 $220 269.5 57.4%
While there is a whole lot more to increased performance than just increasing the air flow, this is a good starting point for further (OCD) ehancements.
-
Just went with the Zippers - it is nice and great price - just have to build out a holder for it...
-
Sitting here after riding home from dinner with nothing special to do, so I thought I'd figure out just how much air a 103 could possibly use. Assuming I haven't forgotten something (old-timers is getting worse all the time), this is how I figured it:
-Assumed volumetric efficiency = 100%
-Maximum RPM = 6200
-Displacement = 103 in3 / 2 = 51.5 in3 per revolution (one intake event per cylinder every 2 revolutions)
-1728 in3 = 1 ft3
51.5 in3 X 6200 RPM = 319300 in3 per minute
319300 / 1728 = 184.78 CFM
Unless one were to drastically improve the volumetric efficiency, increase the displacement, or fit a blower, extremely high flowing filters would be overkill. The regular K&N used with the SE or Ness backplates should be more than sufficient.
Jerry
-
Without even considering the numbers the fly in the ointment there Jerry is usage. A little dust, a little riding, a little dust, a little riding; and the need for overall greater initial levels becomes more important everyday.
-
Without even considering the numbers the fly in the ointment there Jerry is usage. A little dust, a little riding, a little dust, a little riding; and the need for overall greater initial levels becomes more important everyday.
Don,
I agree, the CFM rating will decline as the filter gets dirty. That's why I like K&N's, it's easy to clean and re-oil so it's no big deal to do so at each service interval. I just figure that a filter with 150% of the needed flow should be sufficient, unless you never clean the filter. BTW - did you notice that the stock H-D filter flows only 170 CFM versus a 184 CFM calculated requirement? Imagine how that baby flows after 5 or 10k miles worth of dust and dirt - kind of obvious why we all change the filter as one of the first mods on a new bike.
Jerry
-
I suspect that the MOCO air filter tested was the newer, less efficient, and probably more expensive OEM filter. My understanding is that K&M makes the models for Ness, Zippers, etc. to different specs apparently. Unfortunately you give up 5/8" right side leg room with Zippers. Sacrifices we make huh ?
J.
-
BTW - did you notice that the stock H-D filter flows only 170 CFM versus a 184 CFM calculated requirement?
Yeah, that jumped out big time Jerry. Of course HD is figuring the "stock" requirement against an 88" rather than a 103" but still not leaving much room for error.
-
With the numbers the Zipper's one is putting down, I wonder if there's much filtering going on? [smiley=nervous.gif] [smiley=nixweiss.gif]
-
With the numbers the Zipper's one is putting down, I wonder if there's much filtering going on? [smiley=nervous.gif] [smiley=nixweiss.gif]
It's a piece of K&N manufacture. So I'm not too worried there.
-
The Zippers filter is 5/8 of an inch deeper than the standard K&N unit that would come in a Ness or SE kit. And yes, it is a K&N unit, so filtering should be good. Little tougher on leg room though, but if you are looking for that performance edge....