I have a 540ci with power flo's up to the risers and then out through the transom with just tips , now I have not ran the boat since this has been done just need some honest ideal about how loud it would be boat had silent thunder on it last year , oh this is a wet pipe system also! HELP !

Check this out. My 540 with EMI's

http://www.youtube.com/watch?v=sOQmBWU4jxA

If you are boating the chain I would look into mufflers, I did. My officer buddies are telling me it will be the DB police year.

Thanks for the video and the heads up but most of my running is out on the big lake between Chicago, East Chicago In & St joe or Holland and once in while the St Clair in Mi do'nt think it should a big problem until going into one of the ports up in Mi

We have them on sale....

I would go with the 4" x 6" for your HP

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Kirk

Depends on how loud you want your boat to be,I run stainless marine 3's with 5" tails,my boat is so loud I couldn't stand (people could hear me for miles plus it was just about defeaning at wot)it so I bought ggb's. Unfortunately they are not available anymore,Smitty

I boat in Holland mostly...

I run CMI headers and have had pretty good success with Sound Eliminator mufflers... but I'm not crazy about the design.

1. They tend to wear internally and clank a bit over time. The slots that 3 pins ride on orbitally are slowly opening up.
2. They work because they mostly use water to muffle the exhaust... with standard seawater pumps at an idle and no reduction in water (which gives the mufflers the best chance to be quiet) water actually surges backwards up the tail pipes and out the clamp region in the back... so there's a lot of back pressure and potential reversion if you don't have a big drop in your tailpipe angle.
3. They actually have not gotten my 540's to the legal limit. Running 1 engine, I have seen consistent readings of 92dB.... Two engines - 95 dB - like what they'll make you do for the test.
4. They actually DO rob power... I have noticed an RPM drop when putting them on versus taking them off. I think all mufflers will to some extent though.

That said, I don't think there are many clamp on mufflers that will do better. I've tried several styles and am continuing to use these because they look better than J-tubes and sound pretty nice. My boat is so loud without them that it's almost funny... (I have run without mufflers a few times... )

Holland has been OK to me thus far... just be courteous and don't circle the pier heads and you probably will be OK if you're close to legal.

Smitty,
I believe they are back in business
http://ggb.ca/index.php?page=marine
Dave