----- Original Message ----- 
  
  
  Sent: Friday, August 25, 2006 5:42 
  PM
  Subject: [FlyRotary] Re: Exhaust 
  system
  
  Chris,
   
  My manifold is stuck under the cowl mockup for at least 
  another month and I do not have any pictures. Maybe Dennis can post a picture 
  of his. He is using a swirl pipe and I am going to try a 180 deg bend to get 
  the exhaust pointed in the needed direction. The muffler is cool but the 
  exhaust manifold and pipe are very hot. We are both going to try the muffler 
  inside the cowl with heat shielding and some air blowing over everything. 
  Using a cut down stock manifold there is only one pipe and no 
  collector
  I have concerns about heat in the cowl after 
  shutdown with this arrangement. We shall see. 
   
  Bobby
  
  
  Bobby,
  How long are your pipes before the 
  muffler?  Are either of you putting the muffler inside the cowling?  
  If it runs that cool, it shouldn't be a problem.  
  
   
  Chris
  
    ----- Original Message ----- 
    
    
    Sent: Friday, August 25, 2006 4:08 
    PM
    Subject: [FlyRotary] Exhaust 
    system
    
    
 
    
    Chris,
     
    If I remember correctly you have a Renesis. After 
    hearing Dennis's run-up to 5100 rpms last week I am planning to use the same 
    muffler he has. Here are the specs he gave me. 
    Hushpower II
    Flowmaster Performance 
    Resonator
    12512400
    2.5 in. inlet/outlet
    409 SS construction
     
    This 
    little muffler sounded much deeper and quieter than I expected. No level 
    measurements but it was not unpleasant. We are both modifying the stock 
    exhaust manifold but are trying two different methods of attaching the 
    muffler to it.  Will it hold up is another question. 
     
    Bobby 
    (engine still under sheetrock mud) :)
     
     
 
     
     
    
    
    I've looked back through the archives, and seen 
    lots of different ideas for exhaust systems.  But no real definitive 
    answers.
     
    There is the Cool tube exhaust that has very 
    short pipes,like Bob White posted.
    There is the medium length, no muffler system 
    like Buly has or like Joe Hull has mocked up.
    There is the really long tubes with muffler 
    hanging under belly like Tracy has.
     
    Do we know what the correct length tube is to 
    tune the exhaust for our RPMs?  Does this length include the 
    muffler?
     
    It appears the diameter most used is from 1.5 
    to 2".
     
    What about the different mufflers?  
    I only found two mufflers named in the archive that guys are happy 
    with, the Flowmaster Hushpower II, and 
    the Moroso Spiral Flow Racing 
    Mufflers.  Last year at Shady Bend, Monti 
    talked about noise levels and testing different mufflers and pipes.  
    Are there ant results from that?
     
    I'm ready to start mocking up my exhaust, so am 
    seeking the collective wisdom of the group.
     
    Chris
    
    
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