"under water exhaust" without Butterfly valves and Silent Rider

[Nitrousbird]

1 hour ago, Chia said:

i have those, it is really hard getting them off and is the main reason i haven't installed the fae that i have. I haven't really noticed a noise reduction with the STS (edit STE not STS) compared to other boats that i ride in.

this spring i will be removing the silent rider stock muffler that is inside the boat (Larry at fae is not a fan of this product, stated is causes resonance inside the boat) and installing the fae.

To remove the STE's, use a large, heavy duty strap wrench.  There was a noticeable difference going from flappers to my STE's.  A much bigger difference than STE's to FAE.

I contacted Larry last week regarding the Silent Rider bypass.  Less for sound, more for the space (and perhaps pick up a few HP in the process by decreasing restriction in the exhaust path).  

[Chia]

11 minutes ago, Nitrousbird said:

To remove the STE's, use a large, heavy duty strap wrench.  There was a noticeable difference going from flappers to my STE's.  A much bigger difference than STE's to FAE.

I contacted Larry last week regarding the Silent Rider bypass.  Less for sound, more for the space (and perhaps pick up a few HP in the process by decreasing restriction in the exhaust path).  

thanks, maybe i won't bother with the FAE

Edited March 6, 2017 by Chia

[Michigan boarder]

5 minutes ago, Nitrousbird said:

To remove the STE's, use a large, heavy duty strap wrench.  There was a noticeable difference going from flappers to my STE's.  A much bigger difference than STE's to FAE.

I contacted Larry last week regarding the Silent Rider bypass.  Less for sound, more for the space (and perhaps pick up a few HP in the process by decreasing restriction in the exhaust path).  

Ditto the strap wrench.

On the Silent Rider bypass - when we did my engine & exhaust build there was a lot of debate about "exhaust scavenging".  Which basically means keeping a connection between the two sides of the exhausts so that as the exhaust valves operate on one side of the engine there is assisted flow pulling the exhaust from the other side of the engine (I think I have that right).  So you might increase the flow by removing restriction, but adversely affect the flow by removing the scavenging.  So, to account for that I kept my Silent Rider but removed the guts from it.  I also installed STE's and increased the exhaust size.  My new engine with 120 more HP is now quieter than my old one (at least from inside the boat).  Changes made were ETX manifolds, STE tips, removed guts from the silencer, and ran 3.5" all the way back.  I did it all in one shot, so I can't say which one made the biggest difference.

[Woodski]

2 hours ago, Michigan boarder said:

Just something to add, if anyone has ever seen a go-fast boat, some will have the exhaust come out above the water line on the transom.  I've seen them take off to get up on plane and the water flow out of the exhaust is a LOT....I can only imagine that water splashing into water that is traveling in the opposite direction, then making its way out of the bottom, and definitely a restriction of exhaust gas flow. 

That said - this design works for a lot of people, so if you are not worried about the speed loss and use your boat for surfing, then I think it's the right move.

Got pics of the final product yet?

@Michigan boarder:  Once under way the standard exhaust is also above the water line and you can simply look at the tailpipes to see the water / exhaust gas mix exiting the pipes.  When I am skiing behind my boat, I always look at the pipes during a turn or gap in the action to verify water coming out (and thus the raw water pump still working).  Perhaps just paranoia on my part...

As I noted earlier to your comment on how much, typical pump is 8-10 GPM per 1000 RPM and linear in output relative to speed. 

[shawndoggy]

Just now, Woodski said:

@Michigan boarder:  Once under way the standard exhaust is also above the water line and you can simply look at the tailpipes to see the water / exhaust gas mix exiting the pipes.  When I am skiing behind my boat, I always look at the pipes during a turn or gap in the action to verify water coming out (and thus the raw water pump still working).  Perhaps just paranoia on my part...

As I noted earlier to your comment on how much, typical pump is 8-10 GPM per 1000 RPM and linear in output relative to speed. 

Zactly.  That's why FAE is so nice for surfing -- much better than having a 400hp v8 at or near WOT blaring in your face from 10' away, when the transom comes out of the water and the exhaust is aimed right at the surfer.

This is also why gravity fed ballast systems work.  Fill at rest (submerged), drain at speed (exposed).  

[Michigan boarder]

2 minutes ago, Woodski said:

@Michigan boarder:  Once under way the standard exhaust is also above the water line and you can simply look at the tailpipes to see the water / exhaust gas mix exiting the pipes.  When I am skiing behind my boat, I always look at the pipes during a turn or gap in the action to verify water coming out (and thus the raw water pump still working).  Perhaps just paranoia on my part...

As I noted earlier to your comment on how much, typical pump is 8-10 GPM per 1000 RPM and linear in output relative to speed. 

So at 3500 RPM, assuming 9 GPM, that's 9x3.5=31.5 GPM.  Or a gallon of water every 2 seconds.  Lotsa water.

[Woodski]

@Michigan boarder:  Yes and one reason why the marine mufflers are pretty simple and just a water mixing device, the water is a pretty good sound abater.  Putting the exit tube in the water is even better, but it probably disturbs the fish!

[Nitrousbird]

2 hours ago, Michigan boarder said:

 

On the Silent Rider bypass - when we did my engine & exhaust build there was a lot of debate about "exhaust scavenging".  Which basically means keeping a connection between the two sides of the exhausts so that as the exhaust valves operate on one side of the engine there is assisted flow pulling the exhaust from the other side of the engine (I think I have that right).  So you might increase the flow by removing restriction, but adversely affect the flow by removing the scavenging.  

Except the FAE does that, as it is a Y-pipe.  I'm not sure how well the scavenging effect works in the boat world with all that water in the exhaust, but the FAE takes care of that.

[Michigan boarder]

9 minutes ago, Nitrousbird said:

Except the FAE does that, as it is a Y-pipe.  I'm not sure how well the scavenging effect works in the boat world with all that water in the exhaust, but the FAE takes care of that.

[WAwinegrapes]

actual and verifiable difference between headers and OEM manifolds....amazing difference!  A loss of 65 HP and 25 TQ.

Edited March 6, 2017 by WAwinegrapes
to add text

[WAwinegrapes]

6 hours ago, Michigan boarder said:

Ditto the strap wrench.

On the Silent Rider bypass - when we did my engine & exhaust build there was a lot of debate about "exhaust scavenging".  Which basically means keeping a connection between the two sides of the exhausts so that as the exhaust valves operate on one side of the engine there is assisted flow pulling the exhaust from the other side of the engine (I think I have that right).  So you might increase the flow by removing restriction, but adversely affect the flow by removing the scavenging.  So, to account for that I kept my Silent Rider but removed the guts from it.  I also installed STE's and increased the exhaust size.  My new engine with 120 more HP is now quieter than my old one (at least from inside the boat).  Changes made were ETX manifolds, STE tips, removed guts from the silencer, and ran 3.5" all the way back.  I did it all in one shot, so I can't say which one made the biggest difference.

HOw do you remove the guts from the guts from the silencers?  Do you have any pics?  I have never seen the inside of a silencer.  

 

We never got anal enough to measure the noise level difference, but installing the STE (sorry a previous post I called them STS tips) tips made a huge difference.   When cruising, we could talk rather than yelling.  and could listen to the music without cranking it up to max!

 

I never thought about reaming out the mufflers.  Athough I am not sure I would be that adventurous.

Edited March 6, 2017 by WAwinegrapes

[blk93jeepzj]

26 minutes ago, WAwinegrapes said:

HOw do you remove the guts from the guts from the silencers?  Do you have any pics?  I have never seen the inside of a silencer.  

 

We never got anal enough to measure the noise level difference, but installing the STE (sorry a previous post I called them STS tips) tips made a huge difference.   When cruising, we could talk rather than yelling.  and could listen to the music without cranking it up to max!

 

I never thought about reaming out the mufflers.  Athough I am not sure I would be that edventurous.

At one time my muffler developed a hole at the port in side and I believe that there was a baffle that had broken loose as well.  I took a sawzall and cut the whole thing in half longways.  Fabbed up 2 new input sides out of fiber glass mat and resin.  Cut the old inputs out, fiber glassed the new ones in.  Sanded the outside of the muffler down to glass and put the whole thing back together with a couple new layers of resin and glass.  5 years latter no leaks and still working well.  50 bucks in supplies vs 400 for a new muffler.  

[WAwinegrapes]

2 minutes ago, blk93jeepzj said:

At one time my muffler developed a hole at the port in side and I believe that there was a baffle that had broken loose as well.  I took a sawzall and cut the whole thing in half longways.  Fabbed up 2 new input sides out of fiber glass mat and resin.  Cut the old inputs out, fiber glassed the new ones in.  Sanded the outside of the muffler down to glass and put the whole thing back together with a couple new layers of resin and glass.  5 years latter no leaks and still working well.  50 bucks in supplies vs 400 for a new muffler.  

It is amazing how much folks can save themselves with a little inginuety and perspiration.

 

Had an old I/O decades ago....the wooden stringers were completely rotted...so much, you could grab handful of what used to be wood and now was mooosh!  The boat almost sank as the stringers collapsed and the engine and outdrive tore the surrounding  rubber gasket.  Got the boat back on the trailer and home.  Lifted the engine/outdrive (in the olden days, the engine and outdrive were one unit and both engine and outdrive moved as one to trim it out), so we could cut out the fiberglas and rotted stringers, replaced the stingers with new doug fir, and glassed it in place.  Lowered the engine/outdrive, drilled new holes for the lag bolts and away we went.

 

Total cost was more for beer than the parts to fix.

[oldjeep]

3 hours ago, Nitrousbird said:

Except the FAE does that, as it is a Y-pipe.  I'm not sure how well the scavenging effect works in the boat world with all that water in the exhaust, but the FAE takes care of that.

not really.  If the y was a y and not a t then you might get exhaust scavenging.  With a t you get exhaust pulsing into the opposite bank.

[Chia]

Dang, scavenging you say...Was hoping to use that space for a bank of Johnson ballast pumps.

Was it quieter with the baffles out of the silent rider? IE: is it worth the effort to remove them?

[blk93jeepzj]

Don't think taking the baffles out of the silent rider makes it quieter. Possibly louder and changes the tone. Neighbors have said that mine sounds closer to a 383 hammerhead (2007) that one of them has vs another neighbor with the 340 monsoon (2005).  

My thoughts are the baffles keep more water in the silent rider longer to muffle the sound more. 

[Michigan boarder]

8 hours ago, blk93jeepzj said:

Don't think taking the baffles out of the silent rider makes it quieter. Possibly louder and changes the tone. Neighbors have said that mine sounds closer to a 383 hammerhead (2007) that one of them has vs another neighbor with the 340 monsoon (2005).  

My thoughts are the baffles keep more water in the silent rider longer to muffle the sound more. 

That may be true too.  I'm not sure which of my components affected the noise and how much, since I changed out everything all at once.  But - if you are keeping that much water in the exhaust longer and forcing it out harder with pressure, getting the guts out may make some HP gains.  Just guessing.  Sort of a toss up between the priorities.

[Michigan boarder]

14 hours ago, WAwinegrapes said:

HOw do you remove the guts from the guts from the silencers?  Do you have any pics?  I have never seen the inside of a silencer.  

 

The guts were pretty basic.  The input was a 4" opening from off of the old cast iron manifolds.  Then the exhaust went in thru the silencer and had to make a 180 degree turn thru a 2 7/8" elbow, then out thru a long sweep 2 7/8" tube, into 3" wet exhaust hose, out of the transom thru 3" flappers.  I changed it so that it was 3.5" from the aluminum ETX manifolds, then into the silencer (no 180 degree turn), out of a 3.5" exhaust hose to a 45 degree angle then straight out to the transom, thru 3.5" STE's.

[Ndawg12]

I know everyone is on the edge of their seat for an update on this...but I've found more important issues to deal with on the boat and my welder actually went to work and make money for my company, bitter sweet, mostly sweet though

 

 

[formulaben]

Well, in that case I don't feel like I'm hijacking when I mention that @Michigan boarder motivated me to remove my muffler entirely.  Can't wait to hear the difference.  Once thing is for sure, it certainly opens up a ton of room and will make impeller changes a cinch next time.

[nlouthan]

I pulled my muffler off too.  Ditching the STEs and going to FAE.

Rubber mallet against the STE tips and they came off pretty easy.

[formulaben]

For those interested, I used a heat gun and WD40 to help pry them off.  Went faster than I thought it would to be honest.

[Falko]

On 3/18/2017 at 2:41 PM, nlouthan said:

I pulled my muffler off too.  Ditching the STEs and going to FAE.

Rubber mallet against the STE tips and they came off pretty easy.

What are you going to do with those old STE's??

[jrvs23]

1 hour ago, Falko said:

What are you going to do with those old STE's??

Dang, beat me to it!

[nlouthan]

Sorry, the STEs are already spoken for.