SX 192 Mods

[Shannon]

x4

 

[swatski]

@SamCF Sounds like you should put together a kit - for sale.
(Mostly) OEM/Yamaha parts, too, lol.

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[SamCF]

Drive by from Saturday. I planned on taking all of our gear out and making a run with a light load, but we ended up getting sidetracked trying to wakesurf and the water got too rough. This was around 58 mph. The impeller is off to Dean's Team for a re-pitch, should be a different animal next time around.

 

[haknslash]

Nice! More like "fly by" . Boat looks great and looks like a lot of fun!

 

[DBamaC]

As cool as the trimmable nozzle and new bucket are...I think the exhaust is just too dang cool.

 

[haknslash]

I'd love to see another video but with the boat going WOT away from the camera so we can hear it a little better. Sounds sweet! Is it any louder in the cabin while underway?

 

[SamCF]

I'd love to see another video but with the boat going WOT away from the camera so we can hear it a little better. Sounds sweet! Is it any louder in the cabin while underway?

It's a little louder at WOT, but sounds about the same at cruising speed. The factory exhaust resonates in the pump tunnel, and has a drone at certain rpms. No performance increase in this, I just wanted to get the exhaust out of the tunnel. All of the videos I've posted were with this exhaust.

 

[DBamaC]

If you have a moment to detail how you did the exhaust mod....

 

[SamCF]

If you have a moment to detail how you did the exhaust mod....

Well... I didn't set out to change the exhaust. I was using a cheap hose on my dedicated intercooler line, and it blew off. This starved the exhaust of water and melted the resonator box. I bypassed the resonator with parts from my cold air intake to get thru the day. I liked the sound of it, but the drone at 5000-6000 rpm was bad. I went to the thru hull to avoid the pump tunnel drone.

I don't have a parts list, but it's various pieces of the old exhaust and some 3" pipe. I'm going to redo the piping with 4" stainless steel, but it's low on the mod list.

I'm thinking about a different exhaust tip that can be modded to add an extension to extend under the water line at surfing speed. Also pretty low on the mod list.

Surfing is very relaxing and peaceful, standing 10' from a thru hull exhaust at 6,000+ rpm is not.

 

[haknslash]

It's a little louder at WOT, but sounds about the same at cruising speed. The factory exhaust resonates in the pump tunnel, and has a drone at certain rpms. No performance increase in this, I just wanted to get the exhaust out of the tunnel. All of the videos I've posted were with this exhaust.

I hear ya. I also would love to have the exhaust out of the tunnel. Did you make a block off plate or something to go where the stock exhaust exited into the tunnel? Would love to know more! Those FAE (fresh air exhaust) pipes on the surf boats work great if you want to get the exhaust sound and fumes exiting below the water line. Not sure how it would work or perform on a jet boat but you're the man to find out

 

[SamCF]

I hear ya. I also would love to have the exhaust out of the tunnel. Does your flapper come with a block off plate or something to plug where the stock exhaust was? It may be buried deep in this tread already and I've missed it so I will go back and see if you've shared anything on the exhaust.

It wasn't a kit, so no block off plate. I made a plug using a piece of the old exhaust hose and clamps. It needs some work though.

There is a kit in the Greenhulk store that comes with a block off plate. Probably the better option.

 

[haknslash]

I saw your reply to @DBamaC after I had posted so I went back and edited mine

 

[haknslash]

Do you think something like this could work on our boats with an exhaust like yours?

 

[SamCF]

Yes, that is what I was thinking. They have an added benefit of putting the exhaust in the prop wash. We can't do that, but it would still help.

You would need an extended thru hull tip with some mounting tabs. Grooves cut into the fresh air extension to line up with the tabs on the thru hull. Rotate the extension in place. Maybe a set screw that can be tightened by hand to prevent it from rotating off. Wouldn't be too hard.

I don't want anything under the swim platform to have sharp edges, so I'm still looking for the right parts.

 

[DBamaC]

So you bypassed the resonator box and put in something like this?

https://greatlakesskipper.com/southco-m7-05-9205770-polished-stainless-steel-2-1-2-inch-boat-exhaust-thru-hull-tip-w-flap

 

[SamCF]

So you bypassed the resonator box and put in something like this?

https://greatlakesskipper.com/southco-m7-05-9205770-polished-stainless-steel-2-1-2-inch-boat-exhaust-thru-hull-tip-w-flap

That's it. Mine is 3 or 3.5" though.

 

[DBamaC]

You need to bring that rig to Lake Martin in August and let all us other single engine guys crawl all over that boat. I love your changes, but I’d be more likely to commit if I saw it in person.

 

[SamCF]

You need to bring that rig to Lake Martin in August and let all us other single engine guys crawl all over that boat. I love your changes, but I’d be more likely to commit if I saw it in person.

I'll be working during your August meetup, but I would like to get out and see that area.

 

[swatski]

That's it. Mine is 3 or 3.5" though.

I suppose that should work on singles or twins to replace factory outlet?
One of the very few issues I have ever experienced with the Yamaha engines/drives - is the difficulty starting the engine on the surf side - after a long-ish break. We pretty much narrowed it down to the water pushing into exhaust scenario, and the flapper outlet like yours could be an instant cure!

Not to mention, the factory outlet is just terrible, and it leaks.
(after it loses the "hymen" - seal ring, lol)

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[SamCF]

I suppose that should work on singles or twins to replace factory outlet?
One of the very few issues I have ever experienced with the Yamaha engines/drives - is the difficulty starting the engine on the surf side - after a long-ish break. We pretty much narrowed it down to the water pushing into exhaust scenario, and the flapper outlet like yours could be an instant cure!

Not to mention, the factory outlet is just terrible, and it leaks.
(after it loses the "hymen" - seal ring, lol)

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Not sure how water tight that flapper is, but it stops that rush of water when you come off plane.

You can see in one of my videos that the water in the water box doesn't blow out until 4000 rpm (on the trailer). That's a lot of room at idle for water to be going upstream in the exhaust system.