5" clamp on mufflers and suggestions?
 

Today I had a muffler fall off my boat in 100 ft of water. I have Stainless marine 3 exhaust with 5" tailpipes. My motor made over 1100 hp last time it was on the dyno and I have been running GGB clamp ons with a internal flapper, it actually idles BETTER with mufflers on it than w/o. GGB is back in business again BUT they are NOT making anything close to what I have so they are out of the question, looking for advice, and opinions as to what is a "good" muffler, that can knock the noise down and is actually in stock somewhere as I have to buy something by next wknd for hot boat party in Mi. My mufflers had internal flappers so If I can't get new mufflers by Fri I have to find 5" flappers for now, Smitty

I talked to Hpi/aquapower in Ohio, they can ship me a pair of 5" mufflers today/Summit in Ohio also has Gibson 5" bullets in stock for 300$ less, can't find many real world results on either one , anyone have any input?

My buddy has 4.5 inch clamp on gibson bullets on his blown 598's, stellings headers and dry tails until the end, water dumps in at end of tailpipe. Much quieter than my stellings/dry to tip setup with no mufflers. His boat has a cool sound, quieter and deeper tone. I dont think he's ever ran without them, so cant say anything about performance.

Smitty, I have a used set of the original GGB mufflers. They were on a 6" tail pipe. I don't know how you would make a sanitary fit to your 5 " pipes.....However, that's the best I have to offer.

I use CMI clamp on mufflers. I like them but dont have any experioence w any others. Call CMI

I have a set of 4.5" Gibsons and haven't noticed any reduction in power, although I'm only pushing 700hp. They make a significant reduction in sound levels, without them the sound is deafening. I just moved my rubber flappers from the tips to the mufflers.

Did you ever data log with and without the GGB mufflers?

Not really, boat was stupid load with open exhaust, burbled and ran like crap at idle, the mufflers straightened that right up. I did do back to back runs though back when I only had 945hp and boat ran 92.5-92.7 back then with and without the mufflers, Smitty

Just curious, I'm seeing the wideband pulling out 100 lb of fuel at 5000rpm with the mufflers on, after being tuned without mufflers. Never had a problem with the idle but it is loud.

I can tell you that my afr's on the dyno that were mid 11's or so turned into high 10's/low 11's in the boat and I re-tuned it to about where it was BUT it has alwayss been richer in the boat every time compared to the dyno even before the mufflers so yes, I did pull fuel out too. I never botehered to check the afr's with open headers as I will never run without mufflers, I used to love loud **** now its just gives me a headache, I hear enough noise all day at work!!

Not saying to not run mufflers just thinking there may be a better choice than the GGB.

I did order the Gibsons today, they were only 525$ with free s/h and had them sent to where I am going this thurs. I was also seriously considering the hpi/aquamarine ones built in Ohio but they are 300$ more, I was straight up and told the salemsan on the phone I was looking at the Gibsons for 300$ less and asked if he had any interest in discounting them at all to make the sale (they are built out of better stainless but are about identical in design from what I can tell) and he wouldn't budge so I went with the Gibsons, Smitty

Good info.


Any recommendations on switchable clamp on mufflers. Their fixing to crack down on us on our local lake.Sux

Thanks:drink:

i have been running 5" Gibson for two years with no issue. They seem to be well built.

Rob,
We use the 5" CMI switchable clamp-on's. We use mostly at idle or in the river up to a max 3000 to 3500 RPM. In the lake, we run with them open. I am concerned about excessive back pressure using any switchable muffler at high RPM.

Does the clamp on have a way to thru bolt it thru the existing tail pipe? I hear so many people say one fell off:eek: They allready have hole in them.Yea Im concerned about flow,last dyno was 883.


Smity sorry for treading on your thread.

Get the scuba tank's out go get it back. That’s what we did and my GGB's are still on the boat. Nothing really compares. :drink:

I was going between 60-70 mph in 60-90 feet of water and the extra noise didn't register until I had went about a 1/2-1 miles so no chance of recovery!

There is a hole in the bottom of the CMI muffler. Mark and drill your tail and thru bolt with a SS hex 1/4-20 hex and ny/nut on the bottom side of the tail. You can get your hand/wrench inside the 5" muffler...clean install. Good winter project with the engines removed. You slip the muffers on and use the muffler hole as your drill bit guide.

I just traveled 15 miles through 3-4 footers of some of the worst slop in a Velocity 280 and my Gibsons are still tight, not much else is. It'll take me a weekend to check all the fasteners I can get to.