exhaust noise solutions [Archive]

gmocnik

10-15-2004, 09:21 AM

did not want to hijack any of the important havasu marina threads...thanks to lake racer for his continued efforts....
there is another thread that showed pics of a new boat being rigged with side exiting exhaust...granted, not a solution for many with existing transom thru-hull, or for lower freeboard boats, but in a new boat it seems to me to accomplish several things:
1. you split the sound in two very different directions making the measurement at the rear of the boat much less sensitive.
2. the exhaust routing (longer path to sides) inside the boat would allow for an internal muffler/baffle system
just thought this to be an interesting way to comply...

dirty old man

10-15-2004, 09:44 AM

A lot of SINGLE engined boats (pleasure) do this now very effectively. Its very expensive to do it on twins

Essex502

10-15-2004, 10:02 AM

Second "PLACE"

10-15-2004, 10:09 AM

I guess my only comment is the that the boats I have tested MEET the required noise laws in CALIFORNIA and ARIZONA using the Rex Marine PowerSilencers when installed on through transom, above waterline exhaust. Any additional muffling, in my opinion, would inhibit the performance of the motors we have.
One solution is to have all boats have their exhaust exit BELOW the waterline at idle as my personal boat does. When on plane, the exhaust is above the waterline and significantly noisier but it satisfies the law at idle.
There's really only two ways to quiet a boat...muffle it or move the exhaust exit farther from the noise meter.
Essex, not sure how to past an existing thread here for you to see, but I have some good pics of this exhaust system thru the side. It CAN be done
to boats already rigged and running.

Racer277

10-15-2004, 10:34 AM

Essex, not sure how to past an existing thread here for you to see, but I have some good pics of this exhaust system thru the side. It CAN be done
to boats already rigged and running.
To go along with the other thread http://www.***boat.com/forums/showthread.php?t=60776
here is a pic of the boat at the ATDR last weekend. Very nice, the stainless vent grates near the back are actually exhausts. THe boat moved well, sounded nice, and much quieter than thru transom.
http://www.riverratlife.com/galleries/04/attdr/boats/images/DSCN5844resize.jpg

Second "PLACE"

10-15-2004, 10:40 AM

To go along with the other thread http://www.***boat.com/forums/showthread.php?t=60776
here is a pic of the boat at the ATDR last weekend. Very nice, the stainless vent grates near the back are actually exhausts. THe boat moved well, sounded nice, and much quieter than thru transom.
http://www.riverratlife.com/galleries/04/attdr/boats/images/DSCN5844resize.jpg
Thanks Racer277. Any way you can post JUST the pics of the exhaust on the
thread that racecar.hotshoe posted?

Racer277

10-15-2004, 10:45 AM

Thanks Racer277. Any way you can post JUST the pics of the exhaust on the
thread that racecar.hotshoe posted?
Try this:
http://www.***boat.com/image_center/data/500/1917DSCF0011a.jpg
http://www.***boat.com/image_center/data/500/1917DSCF0012a.jpg

Second "PLACE"

10-15-2004, 10:55 AM

Try this:
http://www.***boat.com/image_center/data/500/1917DSCF0011a.jpg
http://www.***boat.com/image_center/data/500/1917DSCF0012a.jpg
Thanks !
This boat is being rigged w/496HO package. This exhaust is the first one Placecraft has done, but sure more are to follow. The "Below water line" idea
is what really helps, AND is is fairly easy to modify an existing boat w/this system. Great concept. :D

Essex502

10-15-2004, 11:01 AM

Interesting....we also, as I noted, have underwater exhaust on the Essex Sterling...4" tips no muffler. We have tested at 84 db(A) at 39" (new CA law that goes into effect January 1, 2005). However, when on plane, our exhaust is above the waterline.
I'll extend an offer to test the boat shown in the photos so we can determine how quiet it is comparable to others that we've tested.

mud duck

10-15-2004, 11:05 AM

HPI Silencers work very well also. About $1,000 a pair.
http://www.***boat.com/image_center/data/521/452My_Picture0004-med.jpg
http://www.***boat.com/image_center/data/521/452My_Picture0008-med.jpg

Second "PLACE"

10-15-2004, 11:14 AM

I'll extend an offer to test the boat shown in the photos so we can determine how quiet it is comparable to others that we've tested.[/QUOTE]
Thanks....since that boat does not belong to me, I'll pass along the offer.
This boats exhaust will ALSO be above the waterline when up on plane. I think the key here is routing the sound from either side, instead of the transom, to further reduce noise.
Have you had any problems with the Marina at Havasu?

Ziggy

10-15-2004, 11:14 AM

I guess my only comment is the that the boats I have tested MEET the required noise laws in CALIFORNIA and ARIZONA using the Rex Marine PowerSilencers when installed on through transom, above waterline exhaust. Any additional muffling, in my opinion, would inhibit the performance of the motors we have.
One solution is to have all boats have their exhaust exit BELOW the waterline at idle as my personal boat does. When on plane, the exhaust is above the waterline and significantly noisier but it satisfies the law at idle.
There's really only two ways to quiet a boat...muffle it or move the exhaust exit farther from the noise meter.
You know, the other week when I was out there and looking at most exhausts I figured a quick fix would be to put a 90 degree tip and extend it into the water deep enough to baffle it...it may not be pretty but probably functional. I don't know if putting a 90 bend would restrict any more than a set of baffles.
Of course if your exhaust exits above the step it wouldn't be possible or make much sense.
Just thinking out loud here. :idea:

Second "PLACE"

10-15-2004, 11:23 AM

You know, the other week when I was out there and looking at most exhausts I figured a quick fix would be to put a 90 degree tip and extend it into the water deep enough to baffle it...it may not be pretty but probably functional. I don't know if putting a 90 bend would restrict any more than a set of baffles.
Of course if your exhaust exits above the step it wouldn't be possible or make much sense.
Just thinking out loud here. :idea:
Not a bad idea. This is similar to what PLACECRAFT is doing, except the exhaust is routed out to the SIDES, because of the close proximity of engine to transom.
I'm sure there are LOT'S of places trying new ideas as we speak. :idea:

dirty old man

10-15-2004, 11:32 AM

Todd969

10-15-2004, 11:44 AM

You know, the other week when I was out there and looking at most exhausts I figured a quick fix would be to put a 90 degree tip and extend it into the water deep enough to baffle it...it may not be pretty but probably functional. I don't know if putting a 90 bend would restrict any more than a set of baffles.
Of course if your exhaust exits above the step it wouldn't be possible or make much sense.
Just thinking out loud here. :idea:
Saw this already on a couple year old Sleek 28 or 29 foot at the Marina 2 weeks ago. He put them just below the waterline and lauched without any hassle.

Second "PLACE"

10-15-2004, 11:49 AM

I've seen boats that won't start with underwater exhaust, just too sensitive to back pressure. Not sure which model it was, but it was one of the Merc packages. They finally proved it by pulling it up on the trailer, starting the motor and quickly backing in again. Can't shut off anytime...
I have heard that....but ALL of the Tournement style ski boats with Merc
motors all have below water exhaust, and THEY have no starting problems.
Nautique, Tige, Malibu and sanger all have this style exhaust factory.

Big_Gunz_

10-15-2004, 12:48 PM

To go along with the other thread http://www.***boat.com/forums/showthread.php?t=60776
here is a pic of the boat at the ATDR last weekend. Very nice, the stainless vent grates near the back are actually exhausts. THe boat moved well, sounded nice, and much quieter than thru transom.
http://www.riverratlife.com/galleries/04/attdr/boats/images/DSCN5844resize.jpg
That would be my boat. I only have a 5.7 litter engine and it has a "Quick and Quiet" exhaust system installed. There's a switch on the dash that controlls which way the exhaust runs, through the drive under the water (real quiet) or out the sides (when you want to hear the engine run).

Essex502

10-15-2004, 12:53 PM

That would be my boat. I only have a 5.7 litter engine and it has a "Quick and Quiet" exhaust system installed. There's a switch on the dash that controlls which way the exhaust runs, through the drive under the water (real quiet) or out the sides (when you want to hear the engine run).
If you happen to be in Havasu let me know as I'd like to test to see how loud your setup is. The more info we have the more likely we can respond to the noise Nazis.

Big_Gunz_

10-15-2004, 12:59 PM

If you happen to be in Havasu let me know as I'd like to test to see how loud your setup is. The more info we have the more likely we can respond to the noise Nazis.
I sure will, be glad to help out.

Second "PLACE"

10-15-2004, 01:00 PM

Very smart idea. No power restrictions at all?

Steamin' Rice

10-15-2004, 01:02 PM

Below the waterline exhaust can work well, my 21' Hallett had the exhause tipes routed below the waterline and it was great. On higher HP motors, I think that there is a potential issue with reversion if the exhaust exits below the waterline.. The side exit exhaust is an interesting approach..

Racer277

10-15-2004, 01:19 PM

That would be my boat. I only have a 5.7 litter engine and it has a "Quick and Quiet" exhaust system installed. There's a switch on the dash that controlls which way the exhaust runs, through the drive under the water (real quiet) or out the sides (when you want to hear the engine run).
Hi BG,
Saw you at the run, but didn't get to talk to you.
Nice looking boat, it ran real fast, I saw that much.
Sounds great too. Not too loud, just nice.
Next time, I'll say Hi.
R277

Big_Gunz_

10-15-2004, 01:29 PM

Hi BG,
Saw you at the run, but didn't get to talk to you.
Nice looking boat, it ran real fast, I saw that much.
Sounds great too. Not too loud, just nice.
Next time, I'll say Hi.
R277
Sorry we didn't meet up too, and yes, there will be a next time and we'll stop and say "hi" and have a cold one with you. We had a great time during the run and watching all the ***boats fly by us. Now it's time to upgrade the boat after seeing all those boats and what they can do.

Racer277

10-15-2004, 01:34 PM

Sorry we didn't meet up too, and yes, there will be a next time and we'll stop and say "hi" and have a cold one with you. We had a great time during the run and watching all the ***boats fly by us. Now it's time to upgrade the boat after seeing all those boats and what they can do.
Yeah, I feel that each dam run has eventually cost me thousands of dollars when it is upgrade time.
"No the 25 won't be big enough."
"I think we'll need the blue motor"
"Can we put a blower on that?"
:rolleyes: :rolleyes: :rolleyes:

burtandnancy

10-15-2004, 01:38 PM

I've heard of a few boats that won't start with underwater exhausts, not sure if it was a back pressure problem or reversion problem. Some cam profiles won't tolerate water in the exhaust until the very tip and then reversion can still be a problem. I personally like the sound of side exhaust on some models of boat (not V8's) especially big bore, in line 6 cyl diesels...

spectras only

10-15-2004, 02:27 PM

This is the business end of my boat with through hub [super quiet] exhaust with 6.2 MPI's .Gps'd 69.7 MPH . Do you really think a through transom exh would help ? Maybe 2 mph :idea: . This boat had 383's with s/c ,through transom exh, topping out 84 . Not worth the trouble ;) a .The holes are closed up and ,I have a pair of merc silent choice [illegal now in many places] with pump&kit for sale .Any idea how much I should ask for it ? http://www3.telus.net/spectrasonly/mirage%20transom.bmp

voodoomedman

10-15-2004, 05:40 PM

I've got the 496 Mag exiting below the waterline. Starts everytime.

Havasu Hangin'

10-15-2004, 05:47 PM

Here's mine...
http://www.highperformancecars.com/hhangin/cig_transom.jpg
5" tips.

Thunderbutt

10-15-2004, 08:14 PM

There is a guy with a Warlock cat here at LOTO. On the back of the boat there is sheet stainless that covers his exhaust and directs the exhaust down into the water when he is sitting still or moving. They are like a box channel that is pluged at the top. I couldn't see inside the channel, but I think the exhaust tips come out of the boat just like all of ours do and the channel takes the noise into the water. I saw it on a lift, not running.

new F29

10-15-2004, 09:43 PM

Why not just extend the thru transom into the water at idle, on plane just like before. Robert :)

Thunderbutt

10-16-2004, 06:33 AM

Why not just extend the thru transom into the water at idle, on plane just like before. Robert :)
I wouldn't want the exhaust it self in the water.

RiverToysJas

10-16-2004, 06:39 AM

I wouldn't want the exhaust it self in the water.
Why not? Big Cam? I can hear when my tips leave the water while pulling in plane, but it's not a huge differance.
Has anyone ever tried running the exhaust right out the bottom of a boat? Should be quieter and help air-out the hull (or exhaust-out ;) ) the hull. How's that for out-of-the-box thinkin'??? LOL
RTJas :D

Havasu Hangin'

10-16-2004, 06:43 AM

Why not? Big Cam? I can hear when my tips leave the water while pulling in plane, but it's not a huge differance.
Has anyone ever tried running the exhaust right out the bottom of a boat? Should be quieter and help air-out the hull (or exhaust-out ;) ) the hull. How's that for out-of-the-box thinkin'??? LOL
RTJas :D
I would think that would be kind restrictive on plane (go back into your box, Jason). :D