side branch resonator

Discussion in 'Technical' started by beaver, May 5, 2017.

  1. beaver

    beaver southern zeds

    Messages:
    5,765
    Likes Received:
    51
    Trophy Points:
    48
    Location:
    yarra valley
    Got this annoying drone at 1800rpm to around 2500rpm after this point which is around cruising speed in fifth, the drone all but dies out and normal transmission is restored. My exhaust system is 3'' expansion pipes to 3'' cats then 2.5'' pipes to magnaflow center X muffler then 2.5 pipes to magnaflow single 2.5 in 3.5 out mufflers.
    [​IMG][/URL][/IMG]
    [​IMG][/URL][/IMG]
    .
    So enter the branch resonator. See below.
    [​IMG][/URL][/IMG]
    [​IMG][/URL][/IMG]
    Basically the resonator consist of a same size Pipe wielded at 90d to the main exhaust pipe. The important part of the resonator is its length, see the table below.
    [​IMG][/URL][/IMG]
    Here are a couple of links to other forums which go into detail about it.
    http://www.camaro5.com/forums/showthread.php?t=102075
    http://www.camaro5.com/forums/showthread.php?t=214004
    http://www.the370z.com/intake-exhaust/22791-fancy-tech-how-get-rid-exhaust-drone-works-great.html
    I've never herd of anyone here trying something like this? but as you can see(if you do a bit of reading) the american car enthusiasts do and have excellent results, and better yet it wont cost an arm and leg to do. I'm going to give it a go, drone is annoying at best.:bash:
     
  2. ProckyZ89

    ProckyZ89 Senior Member

    Messages:
    3,032
    Likes Received:
    21
    Trophy Points:
    38
    That is sort of cool, however did you not try a normal resonator inline on the exhaust first?
     
  3. AAU54U

    AAU54U Member

    Messages:
    377
    Likes Received:
    1
    Trophy Points:
    18
    Same problem here. Let us know how it goes. Thanks for posting (thanks button not visible on your post).
     
  4. beaver

    beaver southern zeds

    Messages:
    5,765
    Likes Received:
    51
    Trophy Points:
    48
    Location:
    yarra valley
    Before

    the exhaust was put on the car I had no idea it was going to drone like it does, neither did the guys who did the install, although they assumed it may because of the design of the magnaflow mufflers. Anyway they have since said installing resonators wont stop the drone at 130hz ( I know the drone is close to this frequency of 130hz because I have a spectrum analyzer) and would possibly shift it up in the rpm range because its close to natural back round frequency..133hz to 138hz.. this is the frequency where all kinds of materials naturally resonate vibrate giving of sound, a resonator tuned to block this frequency would have to be around a meter long, no really practical.
    The other way around it would be to use chambered mufflers.:eek:
    So its tuned length SB resonators..:) when there on I'll repot back on how they worked or not.

     
  5. TWIN TERROR

    TWIN TERROR Well-Known Member

    Messages:
    1,104
    Likes Received:
    27
    Trophy Points:
    48
    Are you sure the noise isn't coming from the mower ? :D
     
  6. Anti

    Anti 14.7 x 14.7 = 44.1

    Messages:
    7,850
    Likes Received:
    6
    Trophy Points:
    38
    That's freaking awesome I really want to try this, tell us how you go
     
  7. CHILI

    CHILI Indestructable Target

    Messages:
    9,395
    Likes Received:
    94
    Trophy Points:
    48
    Location:
    Sydney, Australia
    Bloody Spoil-Sport!!:br::zlove:
     
  8. tassuperkart

    tassuperkart Its a lie I tell you!

    Messages:
    2,298
    Likes Received:
    23
    Trophy Points:
    38
    Trust the seppos to make something relatively simple, be complicated.
    The humble "H" pipe as close to the diff as you can get it will pretty much eliminate cabin droning.
    E
     
  9. noel0leon

    noel0leon Member

    Messages:
    143
    Likes Received:
    0
    Trophy Points:
    16
    On an unrelated note:

    What is that silver bar behind the diff? HICAS lock bar?

    Also, your paintwork is impressive...
     
  10. beaver

    beaver southern zeds

    Messages:
    5,765
    Likes Received:
    51
    Trophy Points:
    48
    Location:
    yarra valley
    yes

    its a hicas lock bar mate, and thanks...
     

Share This Page