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Air Flow article

6 posts from 6 voices
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  1. recumpendpop

    Interesting info on air flow or lack thereof.

  2. Tuttle3

    I'm beginning to think the airbox mod may not have been such a good idea if Yamaha spent as much time in R&D as Honda. It's still hard to comprehend a K&N filter isn't as good as a stock OEM filter...

  3. DennisM

    I see some problems with that posting in that it does not apply to carbed or closed loop FI systems which can be used nowadays on FI systems or, for air kits that use no box at all.

    1) its claims that todays FI bikes are only open loop systems, thats wrong!

    2) it seems to apply only to the use of an after Marget air box in conjunction with a After Marget filter.

    3) there are air kits out there that do away with an air box completely
    4) there is no mention of carburetor systems.

    here is the quote from that post,

    Quote: but cars are different from current bikes in that they have a closed loop Fi system that can compensate for the air flow variance whereas bikes use an open loop Fi system that cannot automatically compensate. Adding supporting evidence to my theories of air box turbulence you will be interested to know that K&N has developed many different types of turbulence diffuser inserts for many different makes of cars & trucks that lessen intake turbulence when using their filters to increase performance. So far nobody has developed a way to even test for turbulence on motorcycle induction systems let alone cure it... end quote:

    My bike is a prime example, it is a carburetor system and the K&N is not in a Air box, the filter is out in the open with a rain sock, and the results of the dyno testing on my bike shows a definite improvement through out the RPM range.

    Todays FI bikes do use a closed loop system it just has to be re-mapped

    I can see his point only if you decide to use an open loop FI system or, if you use an afterMarget air box on a FI system, it does not apply to all carburetor systems, and some air kit manufacturers do actually test their kits on various bikes on a Dyno.

  4. BuzhBoj

    This kind of stuff makes my head hurt. Can someone please explain the differences between open and closed loop and the reasons for both pro & con. I was thinking of putting on a BAK to go with the Cobra Slipon but now I'm not so sure


  5. jdvass73

    This kind of stuff makes my head hurt. Can someone...

    A closed loop fuel injection system uses a oxygen sensor in the exhaust to measure the amount of oxygen in the exhaust. By doing this ro-tuner\" class=\"ymln\">the system can determine if the system is running lean or rich and can adjust the air/fuel mixture accordingly.

  6. yhoower

    This kind of stuff makes my head hurt. Can someone...

    Me too BuzhBoj! I've been tinkering with my Cobra FMS most of the season but still don't understand the ends and out of this issue. I just keep adjusting and ride it for a while to see how it performs. Seems that every adjustment helps in one range but hurts in another. It's pretty solid where I have it set now though.


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