Exhaust Modifications

[aerolland]

Been looking at all the DIY setups for fresh air exhaust and decided to make the plunge.

Shout out to Trayson - I'm stealing your efforts, but with a couple twists of my own added to maybe allow me to call it my own? [emoji23]

More to come but I thought the group might like a teaser or two...

https://uploads.tapatalk-cdn.com/20180802/286f0978388532026df8094ce1e3bd4c.jpghttps://uploads.tapatalk-cdn.com/20180802/12fc505132f25a6581b50bc0e88574b7.jpghttps://uploads.tapatalk-cdn.com/20180802/90cfa7de67d2ed69ce166733ed25b16a.jpghttps://uploads.tapatalk-cdn.com/20180802/15fddadfff57192ef7207945e3fdb315.jpg

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[996scott]

very interested........:)

[gregski]

I think ABS melts at a pretty low temperature...

[aerolland]

180* is the "recommend" high operation temperature by most manufacturers. It will never see that unless it is run out if the water on the trailer and it's ran to full temp. Lake water cools the down time as well, should be fine.

Several others have been building out of PVC which has a melting point of 140* and they seem to be fine.


If it melts, it melts. Will be replaced with similar shape stainless rolled and welded by me. Just trying to have some low cost fab fun on a short deadline.

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[gregski]

Perfect, I was thinking ABS was lower temp than PVC. I wish I had skills/tools to work SS like that, should be sweet.

[STX]

Very interested in this. Any updates?

[trayson]

ABS works fine. never had ANY problems with temp on it. In fact, I overheated my engine once after the door blew off the water pump and the inside of my exhaust flanges got melty and warped and the ABS on the outside of the flanges was perfect and never had any issues.

I'm intending on changing my downpipe to aluminum (that will be inserted into the threaded cleanout coupler) so I can bend it to an oval (like a wing) that's thinner (like 1.75" like the real FAE) instead of having a 3.5" PVC tube adding that bit of extra drag.

Having exhaust flange extensions (mine are made from SS pipe that was flared at an exhaust shop) is really important IMO because before I had the extensions mine had trouble always retaining the connection where the rubber coupler connected to the exhaust output flange lip.

I do like the big wood tube holders Aaerolland made. My support to the swim deck is made with angle aluminum and I've had 2 instances where the angle bracket I'm using to attach that to the swim deck brackets have actually broke. (it's a little L bracket that snapped, so it'll be easy to step up my bracket game).

[aerolland]

I suck when it comes to updates on stuff like this. Forgot that I hadn't uploaded anything since the 'teaser' photos... sorry!

It has been used now for a season and a half now and I have no complaints. I have lost 1 downtube and had to remake one. Seems to not like the threads in the cleanout tee, the first one unscrewed in the propwash, the second pulled the threads out and broke the male thread fitting. My third one was the shortest Z dimension of all of them (still works as supposed to). I don't think it enjoys crabbing sideways with the surf gate on, it definitely acts as a fixed rudder.

28594

This is an old picture, need to take a daylight one of the latest version of the downtube, glued via threads.

[jph3]

So I have been thinking... walk me thru this.

What if you used flexible exhaust hose (same as factory) and inserted it through the hull/port and then extend the hose to drag into the wave? You could secure it internally with screws, flapper would be an issue I guess. Any thoughts?

[trayson]

So I have been thinking... walk me thru this.

What if you used flexible exhaust hose (same as factory) and inserted it through the hull/port and then extend the hose to drag into the wave? You could secure it internally with screws, flapper would be an issue I guess. Any thoughts?

are you talking about having exhaust hose go thorugh the hull and then downturn into the water under the boat? I.E making the FAE out of exhaust hose rather than PVC?

I'm not sure what you're trying to accomplish, but keep in mind that the reason why you have exhaust flanges is so that it functions as a big through-hull and doesn't allow water to get into the hull. I think that sealing flexible exhaust hose so that water didn't penetrate the hull would be a challenge.

Second, the reason why the FAE joins and has a downpipe in the center is to make it so that the exhaust that's output under water is in the prop wash and doesn't mess up your wave or prevent excess drag.

[trayson]

I went a similar but different route with the cleanout tee. I used an aluminum downpipe. I drilled a set screw into the threads so it can't unscrew.

I had one break of at the threads, but they 2nd one is doing well so far. I found it when you bend the aluminum pipe to have a narrower profile, that it's difficult to avoid having pressure on the threads as the aluminum pipe will tend to go every so slightly oval at the top.

My down pipe is just long enough to be effective, but if we hit some big rollers while surfing and it rocks the boat I can occasionally hear the downpipe come out of the water. But overall it's been a great success. https://uploads.tapatalk-cdn.com/20200515/721fff539c6ecc5810922d3b733fb72c.jpg

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