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Thread: Better fuel mileage, torque

  1. #1
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    Better fuel mileage, torque

    Removing the air box snorkel tube on a 2016 nc700x give you more air and filter dirt isn't concentrated in one spot.

  2. #2
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    Sure, Honda put an extra part to decrease mileage. I would trust Honda engineers a bit more, most likely fluid dynamics is involved.

  3. #3
    Member Jt105's Avatar
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    Can you quantify the difference in torque or mpg?
    I can believe the dirt on the air filter will be less concentrated. Not a big concern for me though.

  4. #4
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    Quote Originally Posted by ducatievans View Post
    Removing the air box snorkel tube on a 2016 nc700x give you more air and filter dirt isn't concentrated in one spot.
    There is nothing in this assertion that is true. The opening in the airbox is nominally the same area as the cross section area of the duct, so removing the duct buys noting there. In fact, without the duct there is just an opening in the plastic and the edge of the opening would create turbulence decreasing the air flow. Concentrated dirt in one area of the filter is irrelevant. Air flow, like heat and electricity will always take the path of least resistance and go around it.

  5. #5
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    Quote Originally Posted by b_rubenstein View Post
    The opening in the airbox is nominally the same area as the cross section area of the duct, so removing the duct buys noting there.
    I don't agree. The "cross area" of the snorkel intake opening is much smaller than the "area" of the air filter "element"........and the filter element is pleated (wavy) creating more square inches of surface (vs a flat element surface). Until someone (anyone ???) performs a before and after test on a Dyno with modifications to an intake system, one cannot say one mod helps, or hurts, performance. Different bikes react to different air system mods........drilling holes in a filter housing (airbox) might increase performance in one bike, but actually harm the characteristics on another bike's system. I do think there is one modification that will increase the performance on just about all bikes: inducing cooler air into the intake housing, which means O2 molecules are denser = more O2 usually means more HP. Some folks believe leaving some "roughness" on the intake ports in a head creates a turbulent air flow, improving performance.......where most all agree, an exhaust port should be "mirror smooth" for best results. Kawasaki came out with the first Ram Air Intake System with their mid-1990's ZX11......two smallish intake openings in the front fairing, running back to the airbox. Kawasaki claimed an extra 10 HP at top speed with this system.......cramming (forcing) a denser air into the intake system. While I doubt our dull NC700X could be modified to "cram" more air into it's digestion system, I do believe there might be ways to "allow" more air into the system vs the OEM snorkel. (the snorkel also serves as a sound abatement system on most bikes..........might call it a "sound restriction"..........hmmmm??)

  6. #6
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    Yes I noticed the deference in torque the first time I road it.Intake noise sound is louder or normal depending on who you ask.72 mpg is easy now.The purpose of the snorkel is noise reduction for sissy not proformance. I don't worship engineers, technical service bulletins are overwhelming on every vehicle long term testing is non-existent these days.

  7. #7
    Super Moderator Better fuel mileage, torque 670cc's Avatar
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    Funny how just about any modification a person makes to a motorcycle results in better performance. The engineers are wrong on most all counts. I’ll bet if you forged your own connecting rods you could increase performance, smoothness, and efficiency.

    The seat of the pants dyno measurements are so easily affected by faith, perceptions, and expectations.
    Last edited by 670cc; 16th May 2018 at 08:51.
    Greg
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  8. #8
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    Quote Originally Posted by Moto-Kafe View Post
    I don't agree. The "cross area" of the snorkel intake opening is much smaller than the "area" of the air filter "element"........and the filter element is pleated (wavy) creating more square inches of surface (vs a flat element surface)
    Which then funnels into a much smaller (than the filter element) throttle body and intake manifold. Cross sectional area is also only one small part of it, lengths and volumes are arguably as important (if not more important) than sectional areas. Consider that completely removing the airbox and filter and allowing the engine to free-breathe at the throttle body will almost certainly kill performance (as well as kill the engine).

    Not guaranteeing that the airbox on this bike was carefully tuned for max performance, however I am confident that the team of engineers at Honda didn't look at it and say "We're going to add this extra part to harm performance in multiple areas with little to no benefit." The only reason to de-tune an intake is for noise abatement, and I can't imagine that the NC700 making so much noise that the box had to be de-tuned to a huge extent.

    Until someone can provide me with one of the following, I will rely on the highly qualified (and paid) team of engineers who designed the system:
    1) Before and after dyno runs that confirm an improvement (multiple runs of each so the data can be properly analyzed, and all variables carefully controlled in all runs), or
    2) A complete CFD work-up of the before and after condition, clearly showing a calculated improvement
    Without one (or both) of these, anyone can claim anything is true with just as much credibility.
    [SARCASM]Hey guys, putting a full can of tuna in your air box will increase HP by 75%![/SARCASM]

  9. #9
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    Quote Originally Posted by ducatievans View Post
    The purpose of the snorkel is noise reduction for sissy not proformance.
    I highly doubt it. Better air flow would be my pick. A large rough hole is not the best configuration for a fluid. Just as a straight exhaust is not necessarily better for an engine.

    I bet the increased torque feeling is due to louder airbox sound.

    Some bikes have variable intake pipe lengths, they would not bother if no pipe was better.
    Last edited by Jos; 16th May 2018 at 08:48.

  10. #10
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    All torqued up........

    Quote Originally Posted by TheIronWarrior View Post
    [SARCASM]Hey guys, putting a full can of tuna in your air box will increase HP by 75%![/SARCASM]
    My Dyno results show that SPAM works much better than Tuna.........."Sorry, Charlie"......

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