Underwater silent exhaust tips

[Falko]

Hello all. New to the forum, just got my first inboard a couple weeks ago, but been boating for many years. I won't get in to the benefits of the Malibu over the other boats I've had in the past, we all know why we go in inboards. But there is one thing that is very surprising to me, the noise level. The boat is the XTI which has the engine 3 inches behind your left ear, but I would have thought the noise level in a high quality boat would be less. But I guess these boats are not exactly meant for pleasure cruising, but the sound bothers the admiral.

Anyway, did a lot of research on the subject and will be adding some noise insulation to the engine compartment this winter, hopefully that will help some. As for the exhaust, looks like the options are the STE and the FAE. Quite honestly, I don't see why no one has ever combined the two with a direct turn and drop under the water. Has this been tried and due to back pressures or addtional spray it was just not successful? I'm a bit of a tinkerer with a fab shop at my disposal. I hate to re-invent the wheel, but if that wheel can be improved a bit....

[jkendallmsce]

Make it and we will buy it.

I have the STE on my LXI and they make a huge difference. also have the insulation in the engine box. It is pretty quiet compared to those LXI that don't have the tips. In fact was suprised just how much of a difference they made...not crazy about the price, but worth it. Just how quiet do you want it?

There was a post about 1 week ago. A fella was selling a set of custom made tips he had made...about the same that talking about making....can't remember what it was called, but I am sure a little searching would find it...think he wanted $450 for them...SS and chromed. He had them off a boat as he was trading for new one....one of those cursed and hated 1%ers!! ha ha

[jk13]

FAE combines to one tip so it's directly behind the prop and doesn't change the wake. It's also ovalized for optimum water flow and minimum impact.

STE are above the water when on plane, just pointing down instead of back with baffles I think. I think extending them below the water line and keeping that round shape would mess with the wake.

Just some things to keep in mind. Try it and see.

Edited September 20, 2012 by jk13

[2008vlx]

STE is really lowering the noise. Had 4 VLX with it and the last one without (they forget them at the factory). There is a huge difference.

STE are standard here in Europe because of noise emission limit.

[jkendallmsce]

FAE combines to one tip so it's directly behind the prop and doesn't change the wake. It's also ovalized for optimum water flow and minimum impact.

STE are above the water when on plane, just pointing down instead of back with baffles I think. I think extending them below the water line and keeping that round shape would mess with the wake.

Just some things to keep in mind. Try it and see.

When the boat is just idling, the tips are at or below water level (depend on fuel level, numder of people in boat, etc.) , but when planing like you said , the tips are ooutta the water by whatever the distance is from the lowest point on the tip to the bottom of the stern...so mabye 6-8 inches?? I am sure it varies from boat to boat.

The SS tips the fella was trying to sell were off the boat, but I was interested if the were below the water level when idling....it would only take say 1/2 inch or so, and I would think they would muffle the exhaust noise quite a bit.

If the STEs are too noisy??, you would have hated the noise level prior to STEs...cause they make a huge difference in noise level. A ski buddy has an LXI w/o the tip, now that is loud....I guess some folks like the rumble of a V8!!

And the thought of something revolving at say 5,000 rpm when WOT about 1 foot from ya does kinda make ya wonder if your life insurance is current/paid up...ya know just in case....there is a reason they install scattershields on high performance cars....Maybe thats why I hardly ever have the ole Bayliner wide open!!

[Falko]

Don't get me wrong, not trying to sell anything. I found long ago that making something yourself would required a selling price far exceeding its value.

The STE obviously lower the noise, but what about CO2? The FAE system gets the exhaust stream below the water for that purpose, but there is a lot of piping outside the boat. I was just curious about a tip that extended into the water with a hydrodynamic shape to reduce drag. Something that I might work on over the winter. Thanks all for the input.

Oh, and I ride a motorcycle that spins to 10,000 and has the pistons pointed at my crouch. The inboard doesn't bother me.

[jkendallmsce]

Don't get me wrong, not trying to sell anything. I found long ago that making something yourself would required a selling price far exceeding its value.

The STE obviously lower the noise, but what about CO2? The FAE system gets the exhaust stream below the water for that purpose, but there is a lot of piping outside the boat. I was just curious about a tip that extended into the water with a hydrodynamic shape to reduce drag. Something that I might work on over the winter. Thanks all for the input.

Oh, and I ride a motorcycle that spins to 10,000 and has the pistons pointed at my crouch. The inboard doesn't bother me.

Good point!! I ride too...if you aint sliding, you aint riding!! KTM 530 EXC..the bike is like a tractor...just keeps pulling

Edited September 21, 2012 by jkendallmsce

[REW]

I have done the motor box insulation and that helps with the motor noise but the exhaust "note" is still there. I had plans for STE until we had to move now my budget looks like a bomb hit it. Maybe in another year or two

[mainekneeboarder]

Hello all. New to the forum, just got my first inboard a couple weeks ago, but been boating for many years. I won't get in to the benefits of the Malibu over the other boats I've had in the past, we all know why we go in inboards. But there is one thing that is very surprising to me, the noise level. The boat is the XTI which has the engine 3 inches behind your left ear, but I would have thought the noise level in a high quality boat would be less. But I guess these boats are not exactly meant for pleasure cruising, but the sound bothers the admiral.

Anyway, did a lot of research on the subject and will be adding some noise insulation to the engine compartment this winter, hopefully that will help some. As for the exhaust, looks like the options are the STE and the FAE. Quite honestly, I don't see why no one has ever combined the two with a direct turn and drop under the water. Has this been tried and due to back pressures or addtional spray it was just not successful? I'm a bit of a tinkerer with a fab shop at my disposal. I hate to re-invent the wheel, but if that wheel can be improved a bit....

I am in a similar position and love to just make stuff. I have made some tips that just extend below the water line with no muffler in them, they clamp on with some old I/O exhaust rubbers and have a rod that holds them down going up to the swim platform. They are oval/V'ed on the end similar to the FAE. We use them when going to a bigger lake that we normally just cruise on and do little water sports while there. They do make a big difference with sound, if the tips were STE to start with it would be very quiet I'm sure, The added benefit we noticed was the angle they are at, pushes the bow down and makes the boat ride a bit better in chop. I can still get the wedge down and it doesn't seem to bother the wakeboard/kneeboard wake too bad (I'm a very intermediate rider thou) the surf wave is affected some, the ski wake actually seems better. Mine are just made out of four inch exhaust pipe, I have been going to do some nice stainless ones for a while now and just haven't gotten around to it.

Edited September 21, 2012 by mainekneeboarder

[1608malibu]

I have just purchased the ste tips for my lxi,wondering if someone can let me know how to install.Cheers