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Gut the Air box on my 02 vfr?

Discussion in 'Mechanics Garage' started by Wtfwasthat, Feb 28, 2009.

  1. Wtfwasthat

    Wtfwasthat New Member

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    Hello Gentlemen!
    I once again have an 02 VFR with k & N filter, full staintune exhuast, Power Commander 3 with powercommander.com website map, 02 eliminators.
    I know that removing the Snorkel on the airbox makes the engine sound beefier. Should I waste my time doing this. I am considring doing it to add any horsepower at all and just the different sound.
    Should I remove the snorkel or just remove the whole airbox and put 4 small airfilters on each ITB (Intake Throttle Body)?
     


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  2. CandyRedRC46

    CandyRedRC46 Member

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    you want to put individual pod filters on? wow i havent thought about doing that since i had a carborated cb750... first off if your looking for any power gains the kn is not gonna cut it. if you have ever seen a kn next to the stock filter or bmc filter you will see that the kn only has about half of the filter area as the other two. kn has already stated that they were trying to keep the same flow rate as stock so basically its just a reusable oem replacement. i would put the kn on ebay, get a bmc filter and gut the box. you can take it one step further and pull the velocity stacks out. i did all the above and would highly recommend it. its a reversible and can easily be done in thirty minutes, so its always worth a try. but the individual filters sounds different... give it a try let me know how it works.

    P.S. i posted some info about this earlier it should still be under mods.
     


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  3. SLOVFR

    SLOVFR Member

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    Might want to check with NorcalBoy on this and see what has worked for him.
     


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  4. Wtfwasthat

    Wtfwasthat New Member

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    Thanks candyred, your words are wisdom!
    I will try all the above and inform you on my results
     


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  5. CandyRedRC46

    CandyRedRC46 Member

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    You are more than welcome! I appreciate the compliment. By the way how did you go about purchasing the staintunes they seem pretty hard to come by and very expensive?
     


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  6. Wtfwasthat

    Wtfwasthat New Member

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    I have removed the air box and used 4 seprate filters (from autoZone) and am Very pleased with the results. My bike sounds like a Repsol ready to fly. AHAHAHAH.

    Here is the link I got mine from: Sportouring Bike Accessories
     


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  7. CandyRedRC46

    CandyRedRC46 Member

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    933 dollars U.S., does that sound right? I think thats what it comes out to...
    So it runs good with no air box and the 4 pod filters? Damn you've got me thinking I shouldnt have gotten that BMC lol...
     


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  8. John451

    John451 Member

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    How about posting some filter pics with Vid clip of them sucking and your Staintunes v4 spuds out music ? :cool:
     


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  9. Vlad Impaler

    Vlad Impaler New Member

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    I'd be interested in seeing some dyno results from the air box mods.
    Entry loss factors for flanged openings = 0.49, but on bellmouths = 0.04.
    Over twelve times the loss to accelerate the air through the opening!
    One step worse is a non-flanged opening, a pipe that just terminates. Entry loss factor = 0.93, over 23X the energy needed to accelerate the air into that opening.
     


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  10. 02 VFR Rider

    02 VFR Rider New Member

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    do you have pic's of air filters and part number from Auto zone, I would like to give that a try.
     


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  11. 300shooter

    300shooter New Member

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    Just my .02 but there has to be some reason Honda put those stacks in , I mean, why add parts if they are of no benefit? Better fuel atomization maybe? Dunno just thinking, oh , there I go thinking again.:crazy:
     


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  12. Vlad Impaler

    Vlad Impaler New Member

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    You are correct about them being there for a reason, shooter. It's not fuel atomization however, that's the function of a properly operating injector and fuel pump. The velocity stacks are there to avoid the rarefaction of the air at the inlet. The trick is to maximize flow with the least amount of resistence. The factors I posted above are the standard loss factors for different types of inlet geometry. The lower the number the easier the air accelerates into the opening. Turning a bellmouth into a flanged pipe, or worse a stright end pipe makes that job much harder and therefore stretches and thins (makes less dense = rarefaction) the air. This is exactly what you don't want to do. What you want is a high velocity charge as close to atmospheric pressure as possible (minimize rarefaction) so when it arrives in your cylinder at BDC it crams into itself and densifies before the intake valve closes. Naturally aspirated engines can see "boost" like this up to around 1.25 atmospheres.
    I'm afraid some folks think that noisy is more powerfull. The real trick is minimizing the disruptions to the air that give you the sucking sound and rob velocity. Then use that density and velocity to fill your cylinder as much as possible.

    I'll see if I can scare up a scan of hood loss factors for those who need some convincing on the theory.
     


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  13. Vlad Impaler

    Vlad Impaler New Member

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  14. CandyRedRC46

    CandyRedRC46 Member

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    I do understand about the flanged pipe, (bottom of the air box) not flowing as good as the rounded off, tapered ends of the velocity stacks. that's why next chance I get I am going to round the openings off as much as possible. Hopefully there is enough material there to permit a good progressive slope. As far as Honda adding parts for no reason... The snorkel and flapper are there mostly to pass noise emissions, and also to promote good velocity and fuelling at low revs i.e. the below 3000 stumble that plagues the VFR's. With the stacks out it does seem to hiccup a bit more at low revs when the engine is cold, but as soon as I'm above 170 degrees this goes away, which is fine with me.
     


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  15. CandyRedRC46

    CandyRedRC46 Member

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  16. Wtfwasthat

    Wtfwasthat New Member

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  17. 02 VFR Rider

    02 VFR Rider New Member

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    how about some pics
    oh link above no work
     


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  18. CandyRedRC46

    CandyRedRC46 Member

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    yeah im not getting anywhere either...
     


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  19. Wtfwasthat

    Wtfwasthat New Member

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  20. vfrdroopy

    vfrdroopy New Member

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    greetings from the Netherlands,
    there is hope in the world. please my friend tell me wish stacks you used and or in com. with wish filter, and do you have pictures of the mods.

    I would be glad to see them.
    Kind regards Marcel Stouten
    Moordrecht
     


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