Exhaust diverter to bottom of hull

« **on:** August 23, 2013, 09:14:20 AM »

I have a 86 Bahner 21' with a Berkeley jet and BBC 454. Just got the engine back from a rebuild and would like to install an exhaust diverter system while I'm putting it back in. I like to hear my radio when I'm idling around the marina.

I purchased some used, solenoid actuated, exhaust diverter valves that are kind of a Y configuration. Coming off my logs and snails is a 4" exhaust hose that heads out the back transom above the water line to the exhaust tips. I have enough room to splice in the diverter and run a 3" hose below the boat but I'm concerned about that and don't want my boat on the bottom of the river or blow my motor by pumping it full of water. Also wondering what tips to use if this isn't a stupid idea.

Is this a bad idea? Anyone have any experience with this?

« **Reply #1 on:** August 23, 2013, 11:35:28 AM »

Quote from: dstocker on August 23, 2013, 09:14:20 AM

I have a 86 Bahner 21' with a Berkeley jet and BBC 454. Just got the engine back from a rebuild and would like to install an exhaust diverter system while I'm putting it back in. I like to hear my radio when I'm idling around the marina.

I purchased some used, solenoid actuated, exhaust diverter valves that are kind of a Y configuration. Coming off my logs and snails is a 4" exhaust hose that heads out the back transom above the water line to the exhaust tips. I have enough room to splice in the diverter and run a 3" hose below the boat but I'm concerned about that and don't want my boat on the bottom of the river or blow my motor by pumping it full of water. Also wondering what tips to use if this isn't a stupid idea.

Is this a bad idea? Anyone have any experience with this?

my Bahner has the tips under the waterline...but I don't think I'd go thru all that....... I'd buy larger speakers......a bigger amp before I'd cut more holes and the hull and the expense of all that plumbing...potential leaks...etc.

but that's just me.

« **Reply #2 on:** August 23, 2013, 12:25:42 PM »

def dont go drilling into the BOTTOM of your boat. no no no.

id say you have 5 options:

1. physically move your existing exhaust tips below the water line. it'll be quiet when idling, and under way they'll be exposed and be plenty loud. you'll have to do something with the existing holes. plug them with covers or fiberglass and paint/gelcoat them away.

2. change your exhaust tips to 4" tips and do slide in silencers/baffles, leave em as is placement wise and it'll be a little more quiet.

3. take your existing tips and do some type of clamp on turndowns externally that point down into the water.

4. take your diverters and plumb them in such a way that it goes to a single 3" exhaust exit with a flapper under the water line.

5. enjoy having a big block.

« **Reply #3 on:** August 23, 2013, 12:35:25 PM »

Quote from: dstocker on August 23, 2013, 09:14:20 AM

I have a 86 Bahner 21' with a Berkeley jet and BBC 454. Just got the engine back from a rebuild and would like to install an exhaust diverter system while I'm putting it back in. I like to hear my radio when I'm idling around the marina.

I purchased some used, solenoid actuated, exhaust diverter valves that are kind of a Y configuration. Coming off my logs and snails is a 4" exhaust hose that heads out the back transom above the water line to the exhaust tips. I have enough room to splice in the diverter and run a 3" hose below the boat but I'm concerned about that and don't want my boat on the bottom of the river or blow my motor by pumping it full of water. Also wondering what tips to use if this isn't a stupid idea.

Is this a bad idea? Anyone have any experience with this?

What?

So you want to have 4 exhaust Ports on the transom?

You nuts?

Have an exhaust crossover built, either aluminum or copper, find some tip mufflers and be done with it.

Your idea, while very creative, will do nothing but cause problems. The Captains Choice kit you bought is for an I/O and is designed for use with very efficient flapper valves. I doubt seriously you will have the real estate required to get them to work and the engine will not get that much quieter (may see a 5db drop).

A better solution would be too buy an I/O, they're quiet.....

Send me your Captains Choice and I'll build you a crossover and mufflers....

I been build you a crossover and find the mufflers for you if you want
Sent from my SGH-T989 using SoCalJetBoats mobile app

« **Reply #4 on:** August 23, 2013, 01:06:00 PM »

Quote from: GT Jets on August 23, 2013, 12:35:25 PM

What?

So you want to have 4 exhaust Ports on the transom?

You nuts?

Have an exhaust crossover built, either aluminum or copper, find some tip mufflers and be done with it.

Your idea, while very creative, will do nothing but cause problems. The Captains Choice kit you bought is for an I/O and is designed for use with very efficient flapper valves. I doubt seriously you will have the real estate required to get them to work and the engine will not get that much quieter (may see a 5db drop).

A better solution would be too buy an I/O, they're quiet.....

Send me your Captains Choice and I'll build you a crossover and mufflers....

I been build you a crossover and find the mufflers for you if you want
Sent from my SGH-T989 using SoCalJetBoats mobile app

Yes, Don't drill more holes!!!!

Like that was stated that captains choice system is for I/O. We used to install those on the new sea ray boats and they were all I/O. because if you want quiet you flip the switch and the exhause exits thru though the outdrive like normal I/O. Flip switch the other way and exhaust is much louder and exits through the nice tips with flappers.

« **Reply #5 on:** September 12, 2013, 07:34:31 PM »

I say put a big ol fockin hole in the bottom!
When you get up to speed, the boat traveling across the top of the water will create a scavenging effect in your exhaust and BOOM!
FREE HORSE POWER!
WHO DOESNT LIKE FREE HORSE POWER!

-beerjet-

« **Reply #6 on:** September 12, 2013, 09:21:35 PM »

Wouldn't it be better to install an electric trolling motor on the bow and leave the big block for speed. I've seen the old dudes with this setup on their fishing boats, So you know this to be a proven method.

dstocker

Exhaust diverter to bottom of hull

muffbro

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GT Jets

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