Best Dry Muffler
 

Hi All, Is anyone able to advise the best muffler than can run dry.
My motor is currently running dry to the tips exhaust with eickert headers.
However, too much cam overlap means I cannot run wet exhausts, but also need to quieten it down for marinas.
Any advice on the best muffler that would help me keep quiet in the marinas. please?

I was looking at GIL Select Sound and CMI After Firing Sound Choice as a couple of options. Are there other options, and what's "best" in terms of combining noise reduction while also not hurting performance.
Thanks


https://cimg3.ibsrv.net/gimg/www.off...4de60d86e4.png

I have GGB in my Skater and It drops it a few DB, Never had anything to compare them to. Not sure if they are still making Marine Exhaust or just doing Snowmobile/ Side by Sides. Might be worth a call.

I've already got the GGB slip in ones - never really noticed much difference running them dry - I think they need a bit of water to really start to work properly, which is the issue here.

Found this excerp from Smitty (articfriends)

Mufflers
 

Damn that is a sweet looking motor

I have two sest of Gibson Clamp on for sale if you want to try them. Great shape. 4" inlet, 4.5" outlet. Best offer and will ship for free.

Gibson Performance Exhaust 110003 - Gibson Bullet Stainless Superflow Marine Mufflers

Thanks.

Ed

Any chance you're just going to burn the rubber hose out . Curious about the cam specs. Do you have deflectors in the stainless band to send the water to the rear.

Have you considered down turns?

https://www.cpperformance.com/c-2201-down-turns.aspx

I ran Gibson clamp ons, on my Eickert dry to tip set up on Innovation 600s. They didnt make the boat quiet, by any means, but did get rid of the very sharp crackle. No issues with burning, etc.. One of my favorite sounds EVER, was lighting them up, and the sound before the water even hit the tips! Neighbors and Wife, not so much:whistle:

I have the Gibson's as well and they take some of the bark out especially idling down the river. But when she gets in to the powerband it sounds awesome. I've run with and without and I can't tell the difference. I've noticed way more difference when I added a 4 hole tapered spacer under the carb. Their truck exhaust uses the same design and I have over 150k on my Gibson truck exhaust.

Its insane how much turndowns are, is there something special about that? I mean you can buy some mandrel bent stainless tube and fabricate them for less than a 1/4 of that price!

If you can find a set of shotguns I’d go that route.

with many holes in flap or without ? Mine where without and worked pretty well.

you could

https://www.summitracing.com/parts/s...+5ba29e50b3ba9

Dominicans have the best dry mufflers hands down. No screaming no matter much horsepower is put through them.

^^^Beers ? Lol

I have three sets of shotguns for sale to fit 4.5" pipes

sent pm

Heres another muffler story: I had a overpowered Baja 272, ran a best of about 99.5 gps. Had 5" stellings style tails, with no mufflers it was give you permanent hearing damage/get pulled over loud. So the water was added right near the tip about 5" past the transom. So it wasnt a "dry" exhaust but real close to it. Put on a set of GGBs, boat noise was tolerable but didnt lose measurable speed when turned up to full kill. Left one of them on bottom of Higgins lake one day at 80+ mph in 75+ feet of water so no chance of finding it. Funds were kinda tight, called GGB, they no longer made clampon mufflers for whatever reason. Bought a set of Gibson clampons cheap new. Expected boat to lose considerable speed, they had a fairly small ID compared to body size. I still broke 99 mph with full kill pulley on, I was actually SHOCKED. BTW, if anyones looking for one GGB 5" clampon, I still have one. I used those same gibsons on my dyno full dry for a while, they tamed noise down, wasnt probably quiet enough to pass a db test with water cops but was better then open headers as far as noise, Smitty

do you remember the part number of the Gibson's? Looking at the 310001 or the 310003 (same thing different style?) Thought my application is 4"

Thanks for the input. An unexpected thing about the eickert manifolds is that the collector on them is only 3.5" - so at the moment, as that's the collector outlet size, it runs 3.5" dry all the way to the tip with a 4" water jacket.
But I am thinking I'll go back to 4" ID tailpipes since that gives me more options for inserts to try (I have some 4" GGB inserts - but as above, they only moderate the crackle)
Looking at available options - does anyone have an opinion on the GIL Select Sound mufflers? Can they run dry and are they effective when dry? And Hardin are listing them - I wonder if they have stock?

Any info on these? I’m dry to the tip with stellings and it sounds spectacular however their ear busters big time. They were supposedly on 1150 hp sc engines with no power loss. ??? 4 1/2”.

https://cimg2.ibsrv.net/gimg/www.off...b876accf6.jpeg
https://cimg0.ibsrv.net/gimg/www.off...c793500e4.jpeg
https://cimg1.ibsrv.net/gimg/www.off...fc0e000af.jpeg

Been along time , I had actually bought them from summit or jegs of all places and were 5", the ads today I see look like same stuff although price has went up substantially

That's interesting.
HPI is currently into Harley performance parts if it's the same guys. https://www.horsepowerinc.net/
Been around for 20 or so years.
Guess maybe they ventured into marine at one time. I was unaware if so.
Pair listed on Ebay.

Figured, i see the listing on summit and about to put an order in after your experience, cheers

did quick search Here are some used hpi 4”
https://www.ebay.com/itm/255892970417

Thought you guys might be interested in how this all turned out.

The end result was a pair of Gil Mufflers on almost completely dry tailpipes (Almost completely - because as it is, I have 3mm pisser in the bottom of each pipe - so that the headers drain down and to try and avoid burning up the mufflers)
In addition, I built water dumps from the tailpipes that splash over the mufflers too. All clamp on so I didn't need to cut too many holes in the transom or deck.

https://mattyorke.files.wordpress.co...ios.jpg?w=1024

All works well and it's turned the noise level in the harbours & marinas from that aggressively loud dry pipe sound to very similar to a full wet setup. Not quite quiet, but not ear bursting any more. Here's a couple of short clips at both idle & fast idle:


While I was doing it all, I also added the biggest old old school EGR valve I could find to each of the headers immediately after the collector - so that when there's negative pressure in the tailpipe at idle, it sucks through this and reduces water being reverted - that also worked well and at idle, it's sucking a good amount of air in through the EGR valve rather than quite as much water back up the exhaust. I hope this means I can add a little more water to the tailpipe tip which should quieten it down a bit more again.

Show us your EGR setup?

Have also got a pair of EGR pumps if needed, but at the moment I don't think they're necessary.
I did question if they would do anything at all - but at idle/fast idle, there's an appreciable amount of airflow going in through them - anything that means I can dump in more water to the exhaust without reversion is good.
The other side of the flange has a lambda sensor in it - for the time being to help me refine the map, but also give options for closed loop cruising in future perhaps.

https://mattyorke.files.wordpress.co...ios.jpg?w=1024
https://mattyorke.files.wordpress.co...ios.jpg?w=1024

Oh, I see. You put some evac u pan check valves to bring fresh air into the exhaust.
What's the cylinder for?

They are the actuators for the butterfly valves in the mufflers - which have a pushrod that goes through the transom rings, red bits below:

https://cimg3.ibsrv.net/gimg/www.off...2cb2d20cd4.jpg

Overall this setup's worked really well - I've tried:

• Full wet exhaust : reversion
• GGB slip in mufflers - dry. no real difference in noise
• GGB slip in mufflers - water at the tip & rubber flaps. Quiet - but lots of reversion
• GGB slip in mufflers - water at the tip & no flaps. Too loud and a bit too wet. Didn't quite get water in the headers, but the collector was wet.
• Full Dry - ear splitting at idle

This is the best so far. Later in the year I'll put a little more water in at the tip and see if that brings the noise down a bit more without reversion.

MadMat,

Those look exactly like my mufflers with the butterfly.
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I was thinking of putting flappers on them to arrest stern wake water coming in. My dry risers are very shallow, but come out high.

Do you have much stern wake impact your mufflers?

It's a single engine rig with aluminium headers & heads, so not too heavy at the stern, although by design I have made my exhausts come out in the standard bravo locations rather than up higher.

If you're interested, you can see some more details of the exhaust setup here : https://mattyorke.com/2023/07/12/arr...2023-upgrades/

I was looking at the mufflers the other day regarding flaps. I don't think they'll "just fit" - the nice rounded shape the mufflers have means they're likely to slide off, I think, although I might consider a bolt to hold the flaps on if it also helps reduce noise a bit more and I can get just enough water in to avoid burning the flaps and avoid reversion. I'll keep you posted if I give anything a go.

Matt, really nice attention to detail in both the project and the documenting.

I feel the more projects like this get documented and archived, the more interest and motivation there will be for young men and women to tackle these in the future, as well as current events.

My concept for the heavy concave tips for flaps....was to make up some stainless pipe pieces about an inch wide at the proper flapper width, and tig it to the muffler, wherever it contacted on the concave.

But I'll have to see how high mine end up riding. Also have very littls water coming out...have 2x weep holes 1/8"top and bottom.

Cams are the hyd BBC Merc 365 Mag. 224° single pattern .510" lift and 115.5 LSA or something like that. So pretty tame for reversion.
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Like your concept of a relief valve in the exhaust system to draw in air at low pressure pulses.
​​​​​
A lot of reverion issues are solved with a simple dam at the bottom of the riser.

Curious what you use the trolling motor for ?
Trolling ? lol

What brand of Fuel Injection is that???--- looks very nice !!!

Thanks. It's a Hilborn mechanical injection manifold that I converted to EFI. More details here.

Madmat, so you were seeing reversion with the full wet Eikert exhaust?

What size engine and cam?

When I inquired about that exhaust, it was recommended I go dry to the tip with a HP 500 carb. But I also read others had HP 500's and saw no reversion with wet.

Thanks

I can’t remember the cam right now (am away from home). But the whole motor is a custom build, originally starting with a bulldog 540 (tall deck). It has a hydraulic roller cam, too.

The design intended to allow dry to the tips and my mk1 tips did this, with ggb inserts and rubber flaps. Like this, but with flaps:

That was definitely far too wet and the motor would bog down. It ran OK minus the rubber flaps as per this vid, but I was still getting water up to the collector, and a bit loud.

Since then, I’ve decided that I want the collector to be almost totally dry, so all variations since then have worked on that goal. Obviously having the collector damp isn’t catastrophic reversion, but it’s more than I want. But if I can have it quiet enough and dry at the collector, everyone’s a winner. It’s nearly there.

The EGR valve, combined with reducing water at the tip to be just enough for muffling and no more, seems to be the ticket.

I looked up the full specs of the cam I'm running:
https://mattyorke.files.wordpress.co...pecs.jpg?w=500
And did a post with more details of the engine here.