Help fund the VFR header

Discussion in 'General VFR Discussions' started by RVFR, Jan 24, 2017.

  1. duccmann

    duccmann Member

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    Sent from my iPhone using Tapatalk
     
  2. NorcalBoy

    NorcalBoy Member

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    Humidity is much more important than temperature.
     
  3. CandyRedRC46

    CandyRedRC46 Member

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    For what it's worth.


    Two Brothers Header and pipercross run
    [​IMG]


    Factory header and kn filter run
    [​IMG]


    Sent from my Nexus 6 using Tapatalk
     
    Last edited: May 10, 2017
  4. NorcalBoy

    NorcalBoy Member

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    Variations in humidity influence the engine’s burn rate characteristics. An increase in humidity reduces the burn rate and increases the combustion duration. This increase in combustion duration has the same effect as retarding the time of ignition.
     
  5. RVFR

    RVFR Member

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  6. vegaquark

    vegaquark New Member

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    You need to get into ecu mapping.. Megasquirt or something... Or this is not going to get any better.
     
  7. duccmann

    duccmann Member

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  8. Full-Force

    Full-Force New Member

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    Go back and watch the video with the staintune. At :16 the bike lays over for about 2 seconds then musters to start pulling again around 18 or 19 seconds in. Kinda weird
     
  9. Gator

    Gator Insider

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    From my experience the mid pipe is almost as important as the header. A guy I know ran an Arata header and can on a CBR 1000, dyno tuned and ran great. Several very experienced guys told him to get their mid pipe to really take advantage of their system. The result was that the crazy price of the mid pipe was well worth it. There is a ton of R&D that goes into the FULL system. This might be your problem.
     
  10. RVFR

    RVFR Member

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    Yep, and so much so that was the first thing Mike thought of, so the Staintune came off to see how it reacted.. It didn't like that. But there is still room here to play, so might have Gabe make a couple lengths to try on for size. I was also wondering the neck down in the 2mm with the Staintune to be of question, but since it ran so well before, Mike didn't think the Staintune is the issue. but yes he did say mid pipes play a important role as well.
     
  11. Gator

    Gator Insider

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    The Arata system that I ran on a CBR 1000rr had the Arata mid pipe, the thing that I noticed right off was how the end the met the headers out flow was larger in diameter and stayed that way unti it tapered down to the size that most all cans fit. I have a full Ti Akra system on a CBR 1k now and it is of similar design but I have been told that the Arata full system was the best ever built for the CBR 1k. I think there were some uber expensive Sato full race systms in Japan that were about as good as the Arata's. Good luck, and at least it seems your having fun.
     
  12. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    Tuned pipes from the factories starting with racing two strokes probably date to the late 1940s. Yamaha entered four factory 250s in the 1958 Catalina GP with three American riders and their roadrace champion, Fumio Itoh (sp??) Same deal on racecars dating back to who knows how long ago.

    Tuned pipes for fourstroke bikes since we know that tuned pipes were done on racecars and twostroke factory bikes sort of indicates that the factory exhaust systems might not be all that bad.

    There's a two part film of Yamaha's entry in the 58 Catalina GP. Other sponsorships out of AMA District 33 might have had some factory tech assistance from the likes of Puch, Maico ect., Most, probably came from the US distributors and or local dealers.

    One story that floated around back then was the a "popular" MC noted for raising hell was on the SS Catalina or the SS Avalon steam ship and when the steamer reached Avalon the headcount was one short.

    I don't know how all those folks coped back then with no grief counselors or rules aboot PC..
     
  13. CandyRedRC46

    CandyRedRC46 Member

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    That is one thing I am thinking about. A lot of highend exhaust systems have stepped primaries/secondaries and collectors, but they step up, not down. This step up (generally 2mm larger) creates an anti-reversion point, where exhaust can more easily move out, than back in. This is usually done on performance automobiles as well, where the old way of thinking was to gasket match everything and now the more recent idea is to port the intake manifold opening 2mm larger than the throttle body and the intake ports 2mm larger than the intake manifold runners. When done correctly on the entire intake and exhaust tract, you generally make power everywhere, as you low rpm intake revesion with out hurting flow rate much.

    What you did, was the opposite. After the collector, you stepped down 2mm which could result in increased exhaust gas reversion (possible power loss everywhere), as well as a slight reduction of flow (possible power loss up top). If you are going to try out some more ideas on the midpipe, before you go modifying the midpipe/staintune you just made, maybe try going with a 4mm larger diameter full length slipon of straight pipe at the header collector. This would create a 2mm anti reversion lip at the collector and could possibly bring your low end back. You could then work on tuning the length on that pipe, to find the optimal length, instead of cutting up the staintune. Then when you find what length works optimally, you could figure out what to do for a muffler. Hopefully that will work and if not, you could just toss the staintune that you have now, back on.

    The other things I was thinking about, were your custom exhaust port/header gaskets, you should double check them and make sure none are protruding into the exhaust ports. Also, when you heat up and bent the primary into place, nothing constricted right? There are no dents in the header right?

    Who knows, maybe the Pipercross filter is holding you back, I would feel really foolish if that were the case, but it would be great if bringing the power back was as simple as tossing the kn back on, though I think if the Pipercross was really as restrictive as people are making foam filters out to be, you would not have lost low/midrange and gained up top. I think if the filter was holding you back, it would be most apparent up top and not on the bottomend.
     
  14. Gator

    Gator Insider

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    Yeah I don't think the more flow out of the Piper Cross has anything to do with it. More fun playing with this project.
     
  15. NorcalBoy

    NorcalBoy Member

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    Making 111hp with a slip on and map, this header should have easily pushed to 120 hp.
     
  16. CandyRedRC46

    CandyRedRC46 Member

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    That is the other thing. A slip on/kn/tune should have put down 100 +/-2whp. It originally dyno'd extremely high. 112whp on a slip on/filter/tune vfr800 is crazy. I question the calibration on that day, but the run last week, even if still high, makes a little more sense. That is the problem with dyno runs a year apart with completely different conditions, you cant be sure if the difference comes from conditions and calibration or the parts/tune being used. I wouldn't be surprised if he put the factory header back on and it lost power.
     
    Last edited: May 11, 2017
  17. NorcalBoy

    NorcalBoy Member

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    It is possible to have good data years apart....but ya can't do it with a Dynojet dyno and all their goofy calibrations and nonsense. I'm skeptical of the whole shooting match.
     
  18. Gator

    Gator Insider

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    A local shop here could make a CBR 1k show 235hp on his Dynojet dyno. lol
     
  19. ksoholm

    ksoholm New Member

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    Does everyone know who Mike Velasco is?
     
  20. OOTV

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