"under water exhaust" without Butterfly valves and Silent Rider

[Ndawg12]

[alpensurf23]

On 2/8/2017 at 1:16 PM, Ndawg12 said:

BTW it's not FAE, it's "under water exhaust"

F-Fresh A- Air E-Exhaust is essentially what sounds like your building and looks like from pics. Watch out splitting hairs there Ndawg you'll end up blinding other boats with a balled head.. I've been running an FAE built exhaust and its the best upgrade Ive done I believe. Watch the edges/ point of your down tube Ndawg could scratch that bald head if working on prop..... Nice project!!!!

[Andrew63]

Did you have some small holes in the pipe where it mates to the plate on the transom, on the underside.

about 3/16"

this is to drain the water from the exhaust when you pull the boat from the water.

[Ndawg12]

51 minutes ago, Andrew63 said:

Did you have some small holes in the pipe where it mates to the plate on the transom, on the underside.

about 3/16"

this is to drain the water from the exhaust when you pull the boat from the water.

Yeah, that will be the last step, the project had a major setback that I don't care to share but we'll get back on track this week hopefully.  

[rugger]

On 2/8/2017 at 0:06 PM, Ndawg12 said:

My first attempt dropped my speed by 2 mph max.  I threw it together quickly myself and used cheap muffler pipe knowing that some day I'd use it as a template for a nice stainless steel version that our company welders could fabricate in their down time.  Welders love tinkering around on stuff like this, I missed my calling

 

Nate, that seems pretty consistent with FAE across the board.  Marginal, and I believe its more or less attributed to drag.  

 

On 2/8/2017 at 0:12 PM, formulaben said:

I would think it would be quite difficult to get water back up in there all the way to the top of the risers.  Somewhere I read of owners removing the muffler and going straight to the FAE and it got even quieter.  I'm planning on doing the same, as it will open up some space and make impeller changes much easier.

 

FAE will tell you flaps really aren't needed, and often is done just for warranty.  I added them to my FAE on my last boat because it certainly doesn't hurt.

 

I would love to hear how removing the silent rider muffler changes things.  I'm considering the same.   Not to mention many Malibu boats have terrible routing and end up with pinched exhaust hose.  I think Malibu is one of the worst offenders of this.   So if you skip the muffler you can fix that too!  

[oldjeep]

On ‎2‎/‎14‎/‎2017 at 8:12 AM, Ndawg12 said:

We should be done today or tomorrrow.

 

not to piss on your parade, but are those really > 90 degree mitered corners on that thing?  

[Ndawg12]

1 hour ago, oldjeep said:

not to piss on your parade, but are those really > 90 degree mitered corners on that thing?  

Yes, 73.9 to be exact.  And I don't like it either.  It's something we're changing due to the setback last week.  

[oldjeep]

6 hours ago, Ndawg12 said:

Yes, 73.9 to be exact.  And I don't like it either.  It's something we're changing due to the setback last week.  

Need a tubing bender, mitered corners have no place in exhaust pipes. 

[minnmarker]

1 hour ago, oldjeep said:

Need a tubing bender, mitered corners have no place in exhaust pipes. 

I've had reasonable luck snooping in the back room of an auto parts store or two looking for things like the best stainless tubing shape.  Last time I found a reinforced rubber hose bend to connect my bilge pump thru hull fitting to the hose so it did not get smashed by the ballast bag.  They've got all kinds of shapes hanging on racks.

[Woodski]

And you can purchase pre made bends from various tubing suppliers - McMaster Carr, Online Metals, Summit, Jeg's, etc.

[formulaben]

FWIW I found a guy on Craigslist doing custom tube bending when I was looking at a project last summer and price was great.  Might be worth a look.

[shawndoggy]

I really want to hear about the setback.  to laugh with you, buddy!

[oldjeep]

24 minutes ago, formulaben said:

FWIW I found a guy on Craigslist doing custom tube bending when I was looking at a project last summer and price was great.  Might be worth a look.

Any monkey can build a tube bender;).

http://oldjeep.com/shop_projects.htm

Just be aware that thin wall exhaust pipe tends to kink in a real tube bender.   This is where you need to decide if you are using tube or pipe for your project.  Also, most tube bender dies are not super happy with stainless unless it is pretty thin wall.

[Bawshogg]

4 hours ago, Woodski said:

And you can purchase pre made bends from various tubing suppliers - McMaster Carr, Online Metals, Summit, Jeg's, etc.

Burns Stainless also.

http://www.burnsstainless.com/u-bends-5.aspx

Ive bought half a dozen u-bends and you wouldn't believe how many bends you can get out of a 180 degree pipe. Built whole header sets with 6 180's. 

You most definetly want to use good stainless in this application. Might as well grab a nice TIG machine too.

 As much as I admire your ghetto-fab skills, I would NEVER hang that thang off my boat. 

I still remember the homemade platform. Keep at bud! It's legit entertainment. ! 

Edited March 1, 2017 by Bawshogg

[Monkeybutt]

Would post pics from my previous epic FAE but need to resize first.  Larry uses 2 45 degree corners to make it work and it does.  Noise and exhaust fumes are night and day.  Any time I'm in someone's boat without it and see the exhaust fumes coming up I feel like advocating ... i can't speak for top speed reduction as i never measured the draft impact.

hope getting my 23LSV unwrapped soon to post pics of FAE coming factory direct.  What is a major difference to my previous one is an additional 'ring' around the pipe gong down .. likely to reduce spray/rooster tail but can't speak for effectiveness until water tested.  My Epic had a pretty bad rooster tail so will compare against that.

Edited March 1, 2017 by Monkeybutt
Pic added

[Ndawg12]

So much negativity, wow!  It is pipe, not tubing, .065 wall which I posted earlier.  It's definitely stout, I saw it hit pavement and bounce 30 feet in the air at 75 mph, that's all I'll share.

[NCVride]

8 minutes ago, Ndawg12 said:

So much negativity, wow!  It is pipe, not tubing, .065 wall which I posted earlier.  It's definitely stout, I saw it hit pavement and bounce 30 feet in the air at 75 mph, that's all I'll share.

Hmmmm.  I think you should share more.  This sounds good.  

[Nitrousbird]

10 hours ago, Ndawg12 said:

So much negativity, wow!  It is pipe, not tubing, .065 wall which I posted earlier.  It's definitely stout, I saw it hit pavement and bounce 30 feet in the air at 75 mph, that's all I'll share.

I have a feeling the landing is what you want to leave out...

[RTS]

19 hours ago, Monkeybutt said:

  Any time I'm in someone's boat without it and see the exhaust fumes coming up I feel like advocating ... i can't speak for top speed reduction as i never measured the draft impact.

Geez...I've been skiing behind inboard boats for 40 years....fumes were never a problem for me or anyone else in/behind the boat.  No one I know ever died of CO poisoning.

You guys want the 'FAE' type exhaust for noise purposes or whatever, that's cool and I can totally understand.  Go For It.

But if you were to 'advocate' when you 'see the exhaust fumes' in my boat...you'd have a short ride to the dock....

 

[WAwinegrapes]

19 hours ago, Monkeybutt said:

Would post pics from my previous epic FAE but need to resize first.  Larry uses 2 45 degree corners to make it work and it does.  Noise and exhaust fumes are night and day.  Any time I'm in someone's boat without it and see the exhaust fumes coming up I feel like advocating ... i can't speak for top speed reduction as i never measured the draft impact.

hope getting my 23LSV unwrapped soon to post pics of FAE coming factory direct.  What is a major difference to my previous one is an additional 'ring' around the pipe gong down .. likely to reduce spray/rooster tail but can't speak for effectiveness until water tested.  My Epic had a pretty bad rooster tail so will compare against that.

HOw do you measure the draft impact?  What is draft impact?

[Monkeybutt]

Quote

HOw do you measure the draft impact?  What is draft impact?

I was referring to the comments made earlier in regards of the loss of top speed - so dragging something thru the water (in this case the fresh air exhaust) will have an impact somewhere.  Now to be honest - as WOT is above 5000 rpm on that Mercruiser engine but the alarm goes off at 5000 rpm regardless and top speed for an Epic was never above 38 anyway my comment is pretty much pointless as I wouldn't see a change in speed (hence impact).

Quote

But if you were to 'advocate' when you 'see the exhaust fumes' in my boat...you'd have a short ride to the dock....

well - as you said skiing ... but surfing puts you a lot closer to it - and no you don't die from it but headaches aren't too funny either.  And most important - I usually have 3 - 4 furry friends with me and they love to hang on the back of the sun deck watching someone surf ... one of my GSDs is a pretty good spotter now ;-)

[RTS]

12 minutes ago, Monkeybutt said:

well - as you said skiing ... but surfing puts you a lot closer to it - and no you don't die from it but headaches aren't too funny either. 

Point taken....I have never surfed behind an inboard or any other boat.  

 

Edit:  Still can't help but think that the FAE type systems are a solution in search of a problem.

Edited March 2, 2017 by RTS

[Monkeybutt]

Well .. anything around boating is a first world problem ;-)  and 30 years ago we were happy with a radio and a speaker pushing 5 watts ?

so yes FAE has a lot to do with noise reduction and my neighbors on the lake have complained repeatedly because the music is much louder than the boat ...

[WAwinegrapes]

16 hours ago, Monkeybutt said:

I was referring to the comments made earlier in regards of the loss of top speed - so dragging something thru the water (in this case the fresh air exhaust) will have an impact somewhere.  Now to be honest - as WOT is above 5000 rpm on that Mercruiser engine but the alarm goes off at 5000 rpm regardless and top speed for an Epic was never above 38 anyway my comment is pretty much pointless as I wouldn't see a change in speed (hence impact).

well - as you said skiing ... but surfing puts you a lot closer to it - and no you don't die from it but headaches aren't too funny either.  And most important - I usually have 3 - 4 furry friends with me and they love to hang on the back of the sun deck watching someone surf ... one of my GSDs is a pretty good spotter now ;-)

it may not be dragging the fae thru the water that is slowing you down.  could be the restrictions of the fae itself. the fae increases the  headloss as the gases escape or are forced out the tip.  restricting those exiting gases may be what is slowing the WOT speed.  Bends and or elbows are very bad  and create mucho headloss.  More restrictions equates to less HP.

Edited March 2, 2017 by WAwinegrapes

[MadMan]

8 hours ago, WAwinegrapes said:

it may not be dragging the fae thru the water that is slowing you down.  could be the restrictions of the fae itself. the fae increases the  headloss as the gases escape or are forced out the tip.  restricting those exiting gases may be what is slowing the WOT speed.  Bends and or elbows are very bad  and create mucho headloss.

I agree, the FAE exhaust design is probably the worst you could come up with for exhaust flow.  It's basically blast the left and right sides at each other, then expect it to make an 90 degree bend.