Offshoreonly.com - Testing of CMI sound elimination mufflers

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- - Testing of CMI sound elimination mufflers (https://www.offshoreonly.com/forums/general-q/124868-testing-cmi-sound-elimination-mufflers.html)

BBB725

03-15-2006 09:05 PM

Re: Testing of CMI sound elimination mufflers

Quote:

Originally Posted by Sonny Spectre 30

When you say spring pressure, I assume you speak of closed to open in that you have to get rollin some get them to open. I am going to be running the Ilmor 625's w/ dry exhaust. Any opinion for that application. Are you running dry or wet exhaust? Wonder if the springs could be changed out top opon quicker or will relax some over time? Was your performance affected?

I'm running wet exhaust and if you take these mufflers apart it would be really easy to change spring pressure. Once they are open they "lock" in place and back pressure is not needed to hold them open and once off plane the vibration from the motor will close them again. I never ran my boat without them but a 42 GTX (1000hp blower motors) ran a before and after and didn't see any effects on performance.

Sonny Spectre 30

03-16-2006 06:11 AM

Re: Testing of CMI sound elimination mufflers

Anyone know why the can't be run dry?

Dueclaws

03-16-2006 08:00 AM

Re: Testing of CMI sound elimination mufflers

Fred-
What did CMI say about installing these inside 5"OD wet exhaust pipes?
Thanks
Due

S4Hadi

03-16-2006 08:48 AM

Re: Testing of CMI sound elimination mufflers

Theoretically, one could keep them in a partially to a full open position via spacers (or other methods) to adjust the sound level at lower speeds?

How loud would they be in the full open mode at idle?

These could be fun :D

Jamal

Too Old

03-16-2006 09:44 AM

Re: Testing of CMI sound elimination mufflers

Quote:

Originally Posted by Sonny Spectre 30

Anyone know why the can't be run dry?

Yes.....there's a rubber seal inside that will burn up without the introduction of water. CMI is currently testing a couple variations with other materials that would take the heat of dry exhaust. I look for a dry version in the not to distant future. :)

Too Old

03-16-2006 09:46 AM

Re: Testing of CMI sound elimination mufflers

Quote:

Originally Posted by Dueclaws

Fred-
What did CMI say about installing these inside 5"OD wet exhaust pipes?
Thanks
Due

Yes John...this can be done. The tails would need to be sent to CMI for the fitment and welding.

Do you have some downward pitch between the tops of the elbows and tailpipe exit?

Too Old

03-16-2006 01:53 PM

Re: Testing of CMI sound elimination mufflers

Here's a better photo of the new design.....

Dueclaws

03-16-2006 02:28 PM

Re: Testing of CMI sound elimination mufflers

Fred-
We'll put a level on the tailpipes to check the down pitch. Will CMI do work on Stellings tailpipes? They once told me they work only on CMI products.
Thanks!
J

Too Old

03-16-2006 02:56 PM

Re: Testing of CMI sound elimination mufflers

Quote:

Originally Posted by Dueclaws

Fred-
We'll put a level on the tailpipes to check the down pitch. Will CMI do work on Stellings tailpipes? They once told me they work only on CMI products.
Thanks!
J

I'll check.....

drpete3

03-30-2012 09:50 AM

So I have 4 of these but changing from SC engines to NA. I was told by one person I should use different mufflers on my NA motors. I really dont want to spend $2000 on new mufflers if these would be safe/fine for my new application.

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