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Update/change/add silencer to 46 Post

Discussion in 'Post Yacht' started by P46-Curaçao, Aug 4, 2014.

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  1. P46-Curaçao, Aug 4, 2014
    #1
    P46-Curaçao

    P46-Curaçao Senior Member

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    I want to reduce the noise of my Detroit 6-71 TI’s, even on the flybridge it’s almost impossible to talk above 1000rpm.

    I Googled a lot and found some solutions, but would like to have some input from you guys on which brand of exhaust muffler to choose, and if an underwater exhaust conversion could be an option.

    Has anybody reduced the noise before?

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  2. RT46, Aug 4, 2014
    #2
    RT46

    RT46 Senior Member

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    I want to follow this thread.

    The only way I know to reduce the noise of a DD is to use ear plugs.
  3. new old guy, Aug 4, 2014
    #3
    new old guy

    new old guy New Member

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    there is a reason that they call them "screaming jimmys"
  4. C team, Aug 4, 2014
    #4
    C team

    C team Senior Member

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    I always loved the sound of Detroits! I was out on my buddy's 46' last Saturday and enjoyed those "screaming Jimmys".
  5. PacBlue, Aug 4, 2014
    #5
    PacBlue

    PacBlue Senior Member

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    Muffler exhaust solutions run the full price spectrum, but I have had good luck working with Bruce Browning at Centek for engines in this power range- Centek Industries - wet exhaust systems, genset pollution control

    They have been able to reduce the exhaust note to acceptable levels on CAT C18's, which is no small feat.

    They may have a solution where you do not have to go to underwater exhaust. You may also want to put some type of carpet underlayment treatment to quite the salon.
  6. P46-Curaçao, Aug 4, 2014
    #6
    P46-Curaçao

    P46-Curaçao Senior Member

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    Marine Exhaust Systems Inc. advised me a T38 Thinline Muffler with an expected 'noise' level of 80dBa at Idle and 95dBa at WOT.

    They think it will reduce the actual 'noise' by 50%...
  7. P46-Curaçao, Aug 4, 2014
    #7
    P46-Curaçao

    P46-Curaçao Senior Member

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    Actually I like them too, but with friends on board on trips for 3-5 hours, it’s also a lonely ride when you are unable to have any conversation (even on the fly bridge)
  8. bobhorn, Aug 4, 2014
    #8
    bobhorn

    bobhorn Member

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    Know nothing about DDs but I inserted some silencers from GGB Exhausts in my two FL SP225s and it made a world of difference. The ones I bought slip into a 4" ID exhaust hose.

    They also have other solutions.

    Bob
  9. ruby, Aug 4, 2014
    #9
    ruby

    ruby Member

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    I think you have to be concerned with reducing back pressure
  10. bobhorn, Aug 4, 2014
    #10
    bobhorn

    bobhorn Member

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    They list HP ratings on their site. Again, I don't know about DDs, but on the FLs they reduced the higher frequency noise which was so annoying. They are by no means quiet, but it is a much more pleasant noise.

    I have no connection to the company, just a satisfied user. I did a lot of searching and there are quite a few different solutions out there. For our setup the inserts were the simplest, and also cheapest, solution.

    Bob
  11. P46-Curaçao, Aug 4, 2014
    #11
    P46-Curaçao

    P46-Curaçao Senior Member

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    Thnx PacBlue, I've send them an email already.

    Inside the salon it's relatively quite, all noise comes from the stern exhaust outlets, I hope I can find suitable mufflers, this makes the boat more enjoyable!
  12. Capt J, Aug 4, 2014
    #12
    Capt J

    Capt J Senior Member

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    I would also contact and ask D'Angelo's marine exhaust in Fort Lauderdale. All they do (pretty much) is exhaust and they also do great work and are good people to deal with.
  13. Bamboo, Aug 5, 2014
    #13
    Bamboo

    Bamboo Senior Member

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    The Sea Deuce with a set of 16-92's is quiet enough to have a conversation at all rpm's in the cockpit and flybridge. It's exhaust is similar to the third diagram from your quote- only the first section after collection which empties into the surge tube is different. Going to an underwater exhaust is asking for issues IMHO. Call up MES in Riviera Beach and ask for advice.
  14. P46-Curaçao, Aug 5, 2014
    #14
    P46-Curaçao

    P46-Curaçao Senior Member

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    Maybe the 33 years old muffler doesn't reduce the noise anymore...

    I'm in the process of contacting specialists now, and will keep you all posted!!
  15. P46-Curaçao, Sep 7, 2014
    #15
    P46-Curaçao

    P46-Curaçao Senior Member

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    **UPDATE**

    I have to take all measurements and make a 'as detailed possible' drawing, to supply the marine exhaust specialists...

    Keep you alle posted!!
  16. Capt Ralph, Oct 4, 2014
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    We have 10" exhaust in the transom. I took a rubber 90 degree Elbows, pointed down and clamped it on. First rev sprayed & splashed water everywhere. Drilled 2" holes in the sides for idle relief. Next time I'll drill these holes facing inward (under the swim platform). The bottom edge was shapes like a thruster tube lip.
    This did greatly reduce the 1000 rpm howell and lowered the sound level. At speed, the exhaust is unrestricted as it dumps into the void behind the transom. Still quieter than original. At idle it blub-blubs but you can give & receive docking instructions without yelling.
  17. P46-Curaçao, Oct 4, 2014
    #17
    P46-Curaçao

    P46-Curaçao Senior Member

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    Not a bad idea Ralph, where have you bought those diameter elbows??
  18. Capt Ralph, Oct 4, 2014
    #18
    Capt Ralph

    Capt Ralph Senior Member

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    I found them at Sailors Exchange in Liquordale (Surplus store). I had looked at them for months and made an offer. I'm anchored out this weekend, despite one heck of a front pounding in from the NW (We had to get off the dock). I'll get some pics up next week.
  19. Capt Ralph, Oct 5, 2014
    #19
    Capt Ralph

    Capt Ralph Senior Member

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  20. IGORMIAMI, Jun 3, 2015
    #20
    IGORMIAMI

    IGORMIAMI Guest

    Could yo place a picture of how it looks?.. we all will appreciate it.
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