The usual mods - any "objective" information on their benefits?

Discussion in '6th Generation 2002-2013' started by irishrOy, Nov 17, 2017.

  1. irishrOy

    irishrOy New Member

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    Heyho and hello guys!
    After having introduced myself I already want to talk about mods, yeah ;)
    Since I most likely won't be able to ride my VFR until next summer on the street, but I still don't want to just sit by and relax, I am thinking about doing the "usual" mods like snorkel, flapper and the pair-valve.

    Sorry if this has been asked already, but:
    Trust me, I have read up on these mods and also used the search-function, too.
    But: Is there any "measurable" gain from doing these things, or are these changes more or less "subjective" and/or make the bike sound better? :)

    Sorry in advance if I've opened a can of worms :D
     
  2. RllwJoe

    RllwJoe New Member

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  3. irishrOy

    irishrOy New Member

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  4. OCLandspeeder

    OCLandspeeder New Member

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    I have no objections to what you do to your bike. The important thing is you enjoy it. And welcome to the VFR World.

    Now if it were my bike, I would not even bother with any of those mods. They do nothing to improve performance.

    De-snorkling increases intake noise.
    Flapper valve disabling will probably take some torque away at low to midrange speeds.
    PAIR elimination doesn't do anything except clean up your engine bay and make it easier to remove the air box.

    Mods I've done that resulted in significant gains in performance was Power Commander 5, Suspension upgrade, and my Factory Pro shift Star & Arm kit. Every time I ride my VFR800 I can feel the difference all of the above makes to my bike.

    And brighter headlight bulbs also make a significant difference.
     
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  5. Jakeoster

    Jakeoster New Member

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    Did the power commander smooth out throttle response?

    As a side note I could be wrong, but on other bikes removing the PAIR system if your running an aftermarket exhaust stops the popping sound when you roll off the throttle.
     
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  6. irishrOy

    irishrOy New Member

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    I haven't got a PC or anything like that installed yet! :D But I'm thinking about picking one up sooner or later, maybe.

    This may seem stupid or weird, to be honest, I actually quite like the exhaust-popping on decel. Easy and cool way to make noise ;) (It pops just a little bit on my stock exhaust, but I am fond of that sound)
    (The stock Viffer is already quite quiet as is, so a little bit of noise here and there is not bad I figure)
     
  7. bigbadbass

    bigbadbass New Member

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    Other than PAIR valve block offs...I've purposely refrained from any other mods on my '98 5th Gen.
    Though I've got a rare Wolf underseat exhaust, I'm currently running the stock pipe/airbox.

    I've replaced thermostat, fuel pressure regulator, injector seals, adjusted valves (11 were off at 30K miles! ), installed iridium spark plugs, performed starter valve synch.....it starts/runs perfect, idle to redline....smooth as silk to boot!
    I did do a Mosfet voltage regulator conversion with some wiring tweaks...reliability related o'course. Charging system perfectly stable after 7 seasons.

    Other than needed maintenance on a 19 year old bike...I tend to leave well enough alone...Honda got this one *right* ......pretty much AS IS.
     
    Last edited: Dec 4, 2017
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  8. OCLandspeeder

    OCLandspeeder New Member

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    The powercommander definitely smoothed the throttle response from off idle, from part throttle, as well as smooth the VTEC engagement to the point where it wasn't noticeable except for the sound.

    If a bike has the small backfiring (popping) upon deceleration I believe it means the fueling is too lean.
     
  9. Jakeoster

    Jakeoster New Member

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    If it was running lean there’d be a lack of spare fuel to ignite to create the pop while exiting the exhaust. The whole purpose of the pair system is to inject air into the exhaust to ignite unburned fuel post engine combustion before it hits the catalyst for cleaner emissions and to extend the life of the catalytic converter.

    I’d kind of like to try a power commander to smooth out the throttle, but I’m looking for a local tuner so I can get it setup on a dyno.
     
    Last edited: Dec 15, 2017
  10. OCLandspeeder

    OCLandspeeder New Member

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    A lean backfire is indeed unburned fuel in the exhaust. It will happen when you shut the throttle quickly, in which case the engine produces a high vacuum, sucking in more air than there is fuel available. When coupled with a free flowing aftermarket exhaust, a lot of this air goes into the exhaust. Unburned fuel does accumulate in the exhaust as the engine revs, whether you have a lean condition or not (hence they put a catalytic converter in there), enough so that if you feed in a lot of hot oxygen as in when you suddenly shut the throttle from revs, this accumulated fuel will ignite and cause that "lean backfire". Probably why keeping the PAIR working with an aftermarket exhaust without the ECM compensating causes the backfiring on deceleration.

    However, if you have correct fueling, most if not all the oxygen that enters your combustion chambers will have enough fuel to ignite inside. So any air that enters the exhaust has most if not all the oxygen burned off already. Hence, no backfire.
     
  11. ClockworkOwl

    ClockworkOwl New Member

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    A relative noob here but here's what I've experienced. Disclaimer: I acknowledge the difference between anecdotal and empirical (of which I have none) evidence.

    2007 VFR Anniversary.
    Flapper, snorkel etc.
    Also did PAIR.
    Noticed that the throttle response was more parabolic after PAIR restriction (I had to work the throttle more after breaking or cornering to get it to respond or from a standstill) and response swooped up gradually... which was smoother but required more working and feel. This was opposed to an unrestricted PAIR where it is more hyperbolic (a minute throttle put it back "on" after cornering, breaking or starting from a stop). Ultimately it felt that power was the same but the RATE at which the power was fed was altered.

    PAIR mod = More work but increased smoothness
    No PAIR mod = On/Off throttle with off-the-shelf predictability

    I'm not gonna lie, maybe it's my newbishness but I prefer the bike with the PAIR intact and working.

    Again, I've read a ton of evidence even explaining there is no PAIR activity after warming up but this is just my experience. I'd also say the bike is significantly louder after PAIR restriction from start to finish but again, no hard evidence of that (FMF Apex exhaust makes it loud as shit already so who knows).

    Hail Players!
     
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  12. OCLandspeeder

    OCLandspeeder New Member

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    Clockworkowl, I'm theorizing that what you are feeling is the drop in midrange response from eliminating the snorkel/flapper, and not necessarily the PAIR block off. The PAIR just injects air into the airbox to clean up emissions and if I'm not mistaken, only happens at closed throttle.

    The snorkel/flapper is the one that increases midrange torque sooner in the RPM range. It's the same peak torque, you just get a small bump below VTEC mode. From my understanding, having a smaller opening in the air box increases air pressure and air velocity at lower RPM, increasing torque at that range. When the engine starts to breath deeper at higher RPM and/or bigger throttle openings, it needs more air to rush into the air box, and that's when the flapper opens up. When you delete the flapper, you let in more air in the air box than necessary at low RPM, thus lowering air pressure in the air box and therefore decreasing the velocity in which air enters the intake stacks. The throttle response feels "smoother" or more "linear" because the midrange torque at lower RPM is not there to provide a more immediate response.

    Many owners mistakenly believe this feeling smooths out the VTEC transition. Well it does because you just took away torque! But you CAN have the torque sooner AND smooth out the VTEC transition by eliminating the true cause of that transition abruptness, which is produced by the stock ECM programming to meet exhaust emissions. Either disable the O2 sensor and/or put a Power Commander in there. Doing both fixes all of the 6th Gen fueling issues.
     
  13. ClockworkOwl

    ClockworkOwl New Member

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    That actually makes sense. I appreciate the info and further proof that I am a VFR noob!

    When I get home from work I am going to completely reverse all mods and take her out... I need to get a better idea of which air/fuel component does what to the feel and alter to my preferences for the bike. Truth is, I like the bike either, any, and all ways so in my mind so far there's nothing to "fix" just tweak.

    Many thanks bruvah!
     
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