2nd Gen JCW R56 JCW - Build Thread - New Set Of Pipes

Discussion in '2nd Generation: 2007+ R55 through R61' started by Metalman, Jan 19, 2011.

  1. Metalman

    Metalman Well-Known Member
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    I thought about the muffler, but that space will be dedicated to baffle chambers. Also, if I keep it in the exhaust pipe as a removable item it would be easier to service.

    I'm thinking the BMW X5 has these in the exhaust pipe up close to the engine and they open up at WOT.

    Hah, I already have three patents, they are more trouble than they're worth, don't need any more trouble. Besides, there probably isn't anything unique in what I'm doing anyway.

    Chuck
     
  2. Bigprfed22

    Bigprfed22 New Member

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    Touche!

    I guess the real problem would be getting the buttfly valve at the right closure distance to mimic the flow rate of the factory exhaust. Tell me you have these tools:ihih: why cant you be closer to VA!


     
  3. iwashmycar

    iwashmycar Active Member

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    I think what Chuck said above is when its "closed" its still say, 80% open or whatever need be, but when open its 100% (minus the rod/disk assembly)

    needs a free spin mode lol... so it can spin like a pinwheel and make some crazy exhaust notes :cornut:
     
  4. Bigprfed22

    Bigprfed22 New Member

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    I totally understand what he meant:Thumbsup:

    Just wondering how the flow rate will be discovered.





    HURRY UP WE NEED VIDS:incazzato:


     
  5. Redbeard

    Redbeard JCW: because fast is fun!
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    Again, I am far from an expert so this is just a thought experiment, but wouldn't the butterfly valve interrupt the laminar flow of the exhaust enough to cause more impedance (back-pressure) than just the difference in measurable cross section of the exhaust?
     
  6. Bigprfed22

    Bigprfed22 New Member

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    Thats what im getting at, the valve closure would have to mimic the initial flow rate of the factory exhaust:Thumbsup:


     
  7. Metalman

    Metalman Well-Known Member
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    So was the question, do I know how to test the flow rate of the stock exhaust versus my experimental exhaust? Well yes.... If you have one of these.... and I do....:D

    [​IMG]
     
  8. Bigprfed22

    Bigprfed22 New Member

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    :wink2: sweet! Would the flow rate be different at different engine speeds/levels of boost, or will it be a general reading?

    I ask out of curiousity thinking about with more force comes more pressure and with more pressure comes more restriction. kinda like current and wires?
     
  9. Metalman

    Metalman Well-Known Member
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    Well, as far as the valve, I'm thinking two positions for simplistic reasons (I don't want to spend all the effort and time to try and make it variable for different engine speeds. One at stock (which would be the default off position) and one at full open.

    Gee officer..... it sure sounds like a stock exhaust to me????:eek:
     
  10. Bigprfed22

    Bigprfed22 New Member

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    I get what your saying but you know more about this than i do and im just asking if it is relative to the electric side of the spectum with resistance/voltage/current if ya know what i mean
     
  11. Metalman

    Metalman Well-Known Member
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    I try not to go there.....
    All I know is electricity is faster than I am....:eek:
    That would be a good question for someone named "Sparky":D
     
  12. Bigprfed22

    Bigprfed22 New Member

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  13. Justa Jim

    Justa Jim Well-Known Member
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    Just tossing a thought out here. What if the butterfly disk were bent slightly in the middle creating a "V", with the point toward the flow. This might cause the gas to be smoothly diverted past it, rather then hitting a wall.

    Jim
     
  14. Metalman

    Metalman Well-Known Member
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    #154 Metalman, Mar 3, 2011
    Last edited: Mar 3, 2011
    I'm not overly concerned about disrupting the laminar flow. It really depends where I mount the valve. If I mount it at the end of the exhaust by the muffler, the gases will see very little disruption.

    What's not known, will there be a reflected wave that travels back to the engine from the valve?
     
  15. Redbeard

    Redbeard JCW: because fast is fun!
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    Thats what I am asking. Just because the valve gives you a cross-section that is the same doesn't mean you will have equal "backpressure", does it?

    Thinking about the "v-bend" I think when it was opened it would create a disruption because of the leading edge being "larger" than a flat plane. However, since we are waxing theoretical a valve with two half-circle blades and a centered hinge would do the same trick when blocking the flow. You still get a "smoother" airflow then when they open the flow they fold onto each other and out of the air flow as much as possible...

    Neat to think about. :)

    Sent from my Droid using Tapatalk
     
  16. Metalman

    Metalman Well-Known Member
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    Yeah, unanswered questions....

    My gauge detects air velocity in feet per minute @ 70F, with graphs for converting to other temperatures from 40F to 1,400F in 200F increments at anything over 100F. Unfortunatly I would need to drill holes in the exhaust to take my readings, which I'm not overly thrilled to do.

    I'll have to really think about this valve idea.

    I can also manage backpressure in the rear muffler itself without a valve, but it wouldn't be as instantaneous.
     
  17. Metalman

    Metalman Well-Known Member
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    Found these two sound clips of the Kreissieg exhaust. Starts out with the valve open, then switches over to the quiet setting in the first video.

    [ame=http://www.youtube.com/watch?v=U5QEz8fvbRY&p=C0601EDBE7A53601]YouTube - MINI Cooper S (07[/ame]

    [ame=http://www.youtube.com/watch?v=bYmnZWyNpYg&feature=autoplay&list=PLC0601EDBE7A53601&index=2&playnext=1]YouTube - MINI Cooper S (07[/ame]
     
  18. Justa Jim

    Justa Jim Well-Known Member
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    What type valve to they use?

    Jim
     
  19. Metalman

    Metalman Well-Known Member
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    I'm pretty sure it's a butterfly valve. But I'm guessing they route it through chambers in the muffler. If you go to their web site you can kind of figure out how they're doing it.
     
  20. Bigprfed22

    Bigprfed22 New Member

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