Let's talk about pipes one more time.

Discussion in 'General Harley Davidson Topic' started by SeaRider04, Apr 7, 2008.

  1. SeaRider04

    SeaRider04 Active Member

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    On stock pipes. Injected engine. If I remove the baffles, they will get louder but are they gonna be louder than saying V&H slip-ons?.

    How about the performance, if the baffles removed from stock pipes, there will be no back pressure in the pipes (I though that's good, no back pressure = no restriction), how important exhaust back pressure does to the engine preformance?.
     
  2. glider

    glider Veteran Member

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    They probably will be nasty loud, not a great sound and it will kill the bottom end torque too. The FI engines need some back pressure to run good. No baffles would work on the top end in a drag bike but on a street bike it's a bad move.
     
  3. silentflyer

    silentflyer Active Member

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    On the subject of baffles, I see different baffel kits in some catalogs, any big difference in the short/med/long "beer can" types as far as performance. Also see "torgue cones" or "power cones" listed, any gains with those, or just snake oil? Thx.
     
  4. SeaRider04

    SeaRider04 Active Member

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    Glider, I'm still not so sure about back presure on FI system(I'm a little slow here), what does it do to FI system?, in another word, at which range does the Fi system needs the back pressure/restriction from the pipes and to helps what (more air/fuel/time/purge...)?. I though once the combustion is completed and get dumps to exhaust pipes, it needs to get out freely so the Intake system can breath easily. Yes/No ?.
     
  5. glider

    glider Veteran Member

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    Some say they work to prevent reversion in the exhaust system, the proper system doesn't need them if the baffles aren't modified.

    It's a science that would take a long time to explain, but like posted above the reversion is a sound wave that travels back up the exhaust and can actually cause fuel to be pushed back out the intake as crazy as this sounds.

    Do a google search for "exhaust reversion" and you will better understand why this happens.
     
  6. readski

    readski Member

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    Glider: Had a set of Rinehart exhaust put on my 04 Heritage (FI)...was told I didn't need any adjustments... is this correct... I am not one to notice much in the way of performance...is it bad for the engine like this? Bike came with original exhaust with baffles removed...you were right...sound was loud but irritating...

    thanks for any comments...
     
  7. glider

    glider Veteran Member

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    These bikes come from the factory VERY lean and I like to add some fuel even with just the slipons and use the TFI for this.
    Slipons will lean it out a bit more in any event because of better flow. Many say that the 02 sensors on the new bikes will do the job but I don feel they do it well enough, they are narrow band and can only adjust for stock components properly. Your bike doesn't have the sensors so either a download (which is still lean) or a TFI would do the job.When you change any component, it takes it a bit further than it was designed to do. Some people say "it runs OK" but they are judging from the seat of the pants and not using a sniffer in the exhaust to see how lean it really is. Lean is hot and sometimes surges, not good in either case.
     
  8. SeaRider04

    SeaRider04 Active Member

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    Glider, did a google and got a good read and understanding about the sound wave/exh. reversion. I thank-you for being patient and the time you spent for such a newbie's questions. Ya da man. Thanks again.
     
  9. glider

    glider Veteran Member

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    No problem, now you see why I didn't try to explain it here.:hii