I am currently trying to figure out which muffler to put on my boat. I was lookin at the Ultra-flo mufflers p/n289-2422 from Jegs. Problem is I believe these are straight through mufflers. I was just told by a local very reputable airboat mfg. that unless the muffler had a baffle in it then it was not legal. Specifically for the broom hanlde check. I believe that what I read just said there had to be an automobile type muffler. Does anyone have a good handle on this.
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Muffler Question
- Thread starter cfth
- Start date
A
Anonymous
Guest
An "automotive style muffler that will effectively reduce sound levels."
A straight-thru muffler won't do that and is playing around with the good intentions of the regulation, which is to ask us to "quiet em' down".
A good pair of reverse flow Dynomax Turbos will do the job, won't cost any more than the other stuff, and you'll probably pick up some torque as a bonus.
BF
A straight-thru muffler won't do that and is playing around with the good intentions of the regulation, which is to ask us to "quiet em' down".
A good pair of reverse flow Dynomax Turbos will do the job, won't cost any more than the other stuff, and you'll probably pick up some torque as a bonus.
BF
BigBoom
Well-known member
http://myfwc.com/Boating/AirboatMufflin ... ements.htm
The FWC enforcement protocol requires that all airboats operated in Florida utilize mufflers to reduce exhaust sound levels.
“Muffler� means an automotive-style sound suppression device or system designed and installed to abate the sound of exhaust gasses emitted from an internal combustion engine and which prevents excessive or unusual noise.
The FWC will not specify which mufflers are to be used on airboats. All airboat owners are encouraged to seek the quietest and most effective muffling device(s) for their particular vessel and engine combination.
There is nothing that says you cannot use a straight through muffler and there is nothing about having a baffle in it. FWC uses Magnaflows which are a straight through design.
The FWC enforcement protocol requires that all airboats operated in Florida utilize mufflers to reduce exhaust sound levels.
“Muffler� means an automotive-style sound suppression device or system designed and installed to abate the sound of exhaust gasses emitted from an internal combustion engine and which prevents excessive or unusual noise.
The FWC will not specify which mufflers are to be used on airboats. All airboat owners are encouraged to seek the quietest and most effective muffling device(s) for their particular vessel and engine combination.
There is nothing that says you cannot use a straight through muffler and there is nothing about having a baffle in it. FWC uses Magnaflows which are a straight through design.
UncleBubba
Well-known member
I would realy like to know. Do to that I've had mufflers put on my boat. It is a strate thought muffler. How ever it did make a big differents in the sound of the boat. The boat was a lot quiter. There was a prop change also.
A
Anonymous
Guest
BigBoom, the newest language may modify that document some as the words "effectively reduce" have been added to the Bill.
You're correct, the FWC is using the mufflers you describe .... and have done so voluntarily. If tougher sound standards are implimented one of these days, they may be forced to go to reverse flow to meet them.
It is important for all of you to understand that it is not the FWC who would be enforcing a sound standard. All they want to see is a muffler. Have a pair and, as far as they're concerned you're good to go. The FWC is our friend. They have been very courteous and helpful in all of this, and all FWC officers deserve our respect and co-operation.
A sound standard is something that would be enforced by local jusisdictions only.
BF
You're correct, the FWC is using the mufflers you describe .... and have done so voluntarily. If tougher sound standards are implimented one of these days, they may be forced to go to reverse flow to meet them.
It is important for all of you to understand that it is not the FWC who would be enforcing a sound standard. All they want to see is a muffler. Have a pair and, as far as they're concerned you're good to go. The FWC is our friend. They have been very courteous and helpful in all of this, and all FWC officers deserve our respect and co-operation.
A sound standard is something that would be enforced by local jusisdictions only.
BF
fatboy0054
Well-known member
BF YES SIR RESPECT YOU GOT IT ! FWC BEEN GOOD HERE ! IT MIGHT HELP IF TWO LIVE IN MY NECK OF THE WOODS 
:shock:
:shock:JUNKJOCKEY
Member
I run the same muffler as fish & game which is Magna Flow . You can stick a rod through it but if they run them it must be OK
A
Anonymous
Guest
Thanks, fatboy.
We're all blessed to have a gentleman in Tallahassee by the name of Capt. Richard Moore, who is the Chief of Enforcement for the FFWCC. He has been nothing less than a pleasure to work with over the past few months, and he and a few others from his Department will very likely be at the Quiet Airboat Demonstration in May ..... not for any other reason other than that they're airboaters too, and interested in helping us keep them.
If you're there, introduce yourself and shake his hand.
BF
We're all blessed to have a gentleman in Tallahassee by the name of Capt. Richard Moore, who is the Chief of Enforcement for the FFWCC. He has been nothing less than a pleasure to work with over the past few months, and he and a few others from his Department will very likely be at the Quiet Airboat Demonstration in May ..... not for any other reason other than that they're airboaters too, and interested in helping us keep them.
If you're there, introduce yourself and shake his hand.
BF
A
Anonymous
Guest
Junk, good to go as far as FWC is concerned.
BF
BF
blackpowderscout
Well-known member
Don't forget to take into account what type of motor you have...an aircraft engine needs to have much lower backpressure psi compared to a car motor. A straight thru may be best for aircraft guys.
Adam
Adam
A
Anonymous
Guest
Yup, you're right Powder .... aircraft motors pump big air. The small reverse flow mufflers kill them with backpressure. Waterthunder and I sometimes disagree on this one (it has to do with the swept volume of the intake, which limits the amount of total flow through an engine), but it takes big mufflers to let an 0520 or 0540 breathe. I'd love to build an 0720 someday and let it have all the intake it could stand. Forget turbocharging .... at sea level it would be a Monster.
Same for the smaller 4 cyl. A/C motors ....... don't try to go too small on the mufflers thinkin' that you're makin' HP. Cubic inches all have to breathe.
Same for the smaller 4 cyl. A/C motors ....... don't try to go too small on the mufflers thinkin' that you're makin' HP. Cubic inches all have to breathe.
blackpowderscout
Well-known member
I'm not a motorhead so I don't have any numbers but my 470 runs better with the bigger ultraflows than with the smaller thrushes I had before. Granted these are straight thru vs the turbo before but it seems the motor likes these better.
I don't know exactly what the tolerances for backpressure psi for mufflers in aircraft applications are but from the little bit of info I've found it is definitely less than is allowed for car motors....maybe this muffler thing is a giant conspiracy to get rid of aircraft engines on airboats????? :wink:
Adam
I don't know exactly what the tolerances for backpressure psi for mufflers in aircraft applications are but from the little bit of info I've found it is definitely less than is allowed for car motors....maybe this muffler thing is a giant conspiracy to get rid of aircraft engines on airboats????? :wink:
Adam
Now Adam we need no talk of conspiracy on here LOL just kiddin. I hope your wrong about the mufflers getting rid of the aircraft engines but it mat be that if push ever comes to shove the prop noise will kill them. The brite sid eis that they are not that much lighter than chevy v8 anyways and chevy is definately cheaper to work on. I compared the two types when I got back into airboats and it was a no brainer for me. I spent less on my v8 than I would have on a 300hp aicraft and I can get parts to work on it. I know ya'll all ahve heard the story and real airboats run aircraft but the first airboats by the seminoles i believe used model a engines in the bottom of the boat with belts up to the prop wish I could find a pic of one of those. It wasn't until after wwII and kores that a/c engines mostly the groundpower unit engines became readily available to the public at an affordable cost.
Hows this for gettin somethin goin again LOL and I been bein so good.
Hows this for gettin somethin goin again LOL and I been bein so good.
It's just cubuc inches and RPM. An O-360 needs the same or a little more flow as a 350 V8. That O-470 needs about what a 500 Caddy needs or a 455 Buick or Olds or 454 GM. etc. Same for 520s and 540s and the 500+ monster motors available for your driving pleasure now
There is a flow efficiency for any given design but in general, if it works for a 454 it should work for an O-470 and vice-versa. For what were talking here the number of cylinders is pretty much irrelevant. Just cubes and RPM. Whats good for the goose is good for the gander.
If ya just assume 100% efficiency youll have more than enough flow in the mufflers. Remember too that unless your running a single muffler you will have to divide by 2 for each muffler size. So the mufflers will again be about the same as duals on an equivalent cubic inch auto engine.
Talking normally aspirated engines here, turbo engines are even more lax about what kind of exhaust ya stick on em.
Scotty
There is a flow efficiency for any given design but in general, if it works for a 454 it should work for an O-470 and vice-versa. For what were talking here the number of cylinders is pretty much irrelevant. Just cubes and RPM. Whats good for the goose is good for the gander.
If ya just assume 100% efficiency youll have more than enough flow in the mufflers. Remember too that unless your running a single muffler you will have to divide by 2 for each muffler size. So the mufflers will again be about the same as duals on an equivalent cubic inch auto engine.
Talking normally aspirated engines here, turbo engines are even more lax about what kind of exhaust ya stick on em.
Scotty
darkwing duck
Active member
I run a gpu and have MAGNAFLOWs on mine and it has helped tremendously with noise reduction. At idle I can talk to any boat or person in or next to me with no problem. I have tested the motor and when I find DECIBEL readings I will post and it was amazing how much difference. The mufflers are not quite a straight thru design but the ar close and have a great baffle to boot. It has not hurt or hinderd my engine performance. The mufflers have been on a little over a year and not one problem.
blackpowderscout
Well-known member
duckluv26":ku2gngmd said:
The time will come......
Florida will fill up with Yankees and illegals sometime so they will eventually discover what a great place Texas is to retire. For all of you who currently live up north....Texas is awesome!!! The weather is great as is the scenery and it isn't as crowded as Florida!!!! Check it out. HEHE!! :twisted:
Adam
Hey Duck enjoy em while you can we ran that way for years here as well. As people move in old ways will move out it is just a natural progression of life.
A
Anonymous
Guest
Duck, you might be surprised at how much nicer it is to run and actually talk to somebody ...... :shock: .
Hand signals are a pretty small vocabulary.
BF
Hand signals are a pretty small vocabulary.
BF
Airboatcapt2
Well-known member
I think he means that we don't have the cranky retiree's moving in on our waterways and taking over the majority population then controlling our waterways.