Exhaust/Mufflers
 

What is the best exhaust system to maintain dB compliance of under 90 without a power or speed loss for a ProCharged 7 psi and Injected motor about 825 HP?

I'm currently working on building some turn downs with mufflers built in. I run on the Chain as well and as you know noise is the hot topic right now. I will try to keep you posted with details. I plan to market my design soon for local guys. I am also building some 850 hp motors so what I design should work for you as well. I am hopefully going to be 50% less cost than what is out right now.

Smitty

You might try GGB. They work well on my 750 HP normally aspirated.

Exhaust/Mufflers
 

I recently tried the CMI Sound Elimination mufflers. Quiet @ idle and open up as exhaust pressure increases. Not quite as loud at WOT. No loss of performance. 540 600 hp motors in 35' Cig.

I run GGB Extremes on my 725 HP, NA 540. They work great, however, as far as I know they are no longer in business.:(

How much for CMI mufflers?

I am running 4" Bola SS mufflers and Drew shotguns. 88dba at idle, takes the bite out of the wot.. breaths freely. Not the prettiest, but it is functional. The noise cops havent pulled me over yet...

I'm running GGB's with turndowns...

600 hp 509 with Keith Eickerts.

Only 83 db's at idle, NO power loss..:D

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I see GGB's website is up again... don't know if their still in the "marine" side of things though...
http://ggb.ca/


Doug

Getting the pontoon ready Bob?

I modified a set of stainless 5" HPI's by cutting 90 degree stainless tubing and welding to HPI out lets.

They are very quiet even at speed all you here is blower wine.

They did however bring our EGTs on our 1300hp engines up to an unacceptable temperature level at high rpm.

I believe the HPI's would work well up to 1000hp or or so as they are similar to my GGBs and they worked real well on my Gun with 850HP mills with no noticeable power loss and acceptable EGT's..

Good Luck, I'm still searching for something that will work on my set up, I would be happy with 100dbs at idle.

Smitty, Just a thought for your turn downs,I've considered an adjustable plate/perforated grate that slides over matching slots/holes in the elbow.

The design would serve back pressure as the tips are under water (addressing reversion) and subject to perforation/louver design, influence exhaust tone.

Show us pictures or at least,keep us posted.

How did ya guess???

Me too, IL. law is 90 and the dB police sound like their perking up this year.

Anyone tried Zoomers? They had a great review in a 2004 Hot Boat issue.

GGB's latest location.

Nice

Hey Rbeyer, I just bought and installed a set of short barrel through transom Zoomers on my boat. The hot boat article on mufflers was March 2005. Zoomers supposedly helped top speed when installed on a boat. I feel that isn't very probable, but I hope the loss is minimal. They look good to me, all 304 stainless construction, I saw a thread on hot boat where someone was complaining of corrosion issues after one season of freshwater use. Hope its not true, I will see this coming summer.
I decided to give them a try after reading the hot boat article. I got a great deal on them from Trick Marine- 275.00 shipped to my door. Really. (I know I probably just ruined this thread.) Anyway I will let you know what I think of them when I can first test them.

Rob -

The CMI Sound Elimination Mufflers work great honestly.

Muffled at idle and open while running yet take the bark out of the exhaust.

Zastrow ran them right around 900 HP and passed with Lake County.

Let me know what size and if you want clamp on or transom mount and I'll get you pricing. Email me at [email protected]

Merry Xmas,

Kirk

GGB is still in business contrary to rumors to the contrary. However, they are selling on a very limited basis and are very selective of what resellers they will use.

I'm happy to say we do sell GGB. The Extremes are no longer available only an insert. It's too bad, the Extremes where a great product for most applications. I think they ran into some QC issues with a few and then dropped the design.

zoomers
 

I run Zoomers on a Whippled HP 500 in a 2750 Lavey- runs in the low 90's speedwise. Sound is fine(not as nice as before tho) and the noise police never give me a second look. Don't think they affected performance at all.

[QUOTE=Pantera28-650HP;2379792]Rob -

The CMI Sound Elimination Mufflers work great honestly.

Muffled at idle and open while running yet take the bark out of the exhaust.

Zastrow ran them right around 900 HP and passed with Lake County.

Let me know what size and if you want clamp on or transom mount and I'll get you pricing. Email me at [email protected]

Merry Xmas,


Kirk
This in my next door neighbor,so be nice with those prices

I bought a prop or two from him. If he emails me i will give him the TB Discount!!

Honestly they are great mufflers both in looks and performance.

[QUOTE=boatnt;2380199]Thanks Tom

Thanks

Thanks for your input. Look foraward to the update.
Bob

try drew marine shot guns, they work great and are priced great

Here is what I did on my 38 Cigarette w/1100h.p. Psi blowers. They are under water @ idle and all 4 are between the drives and pointing downward, when up on plane.
A "little bark" when coming up on plane, but at speed the sound is quite acceptable. I have not done a db check at idle or cruise, but will do so next boating season and post the results.

Very cool, looks expensive.

I ran the GGB's with 1000+ HP for a couple seasons. They worked great. I did have a weild break and switched to the CMI Sound Elimination Mufflers for a while. They worked just as well, but I liked the GGB look better. For current models available the CMI are my choice. I do have two sets of 4.5" CMI's for sale, 4.5" clamp on. One set is new and the other has about 20 hrs.

How much would you be asking for them?

$600 for the used pair and $900 for the new pair.

RBeyer.
They are 4" 304ss, made with 2 U-bends, 2 90's and several feet of straight. It took a friend of mine that is a whiz at race car fab., 15-18 hours to fab. and weld.
The only thing that I would do over is to have the round plates that hold them to the transom made out of a thicker ss than I used. When he welded them to the tubing they warped and it took a lot of effort to make them flat.