[Eric]

Corey, I can read the sensor resistance and put the calculated boost or temp in the network using the arduino. I am however now more concerned with Tony’s (and your) opinion of the exhaust design overall. What do I need to do to fix it, or at least make it better?

[Eric]

Tony,
there appear to be 2 concerns here,

1) At shutdown, any water in the fiberglass tube from mixer to muffler could flow back STRAIGHT into the engine. Rocking the boat could be enough to do this…
2) Failure of the mixing elbow due to corrosion would send water straight into the engine.

Given that I have every little room to work with, a 2-3 inch spacer between the elbow and the mixer would raise the mixer 2-3 in higher and the angle of the fiberglass tube would increase, thus helping drain it after shutdown. Keeping engines running when rocking will also help. We dive a lot and I like to kill engines when waiting for divers or when they are boarding, but in 2-3 ft seas, I’m rolling. Reducing size of muffler could also effectively increase the angle, but this is not practical…

Switching to a stainless mixer and/or installing a fresh water flush would reduce chance of (2)

What are your recommendations? I simply don’t have room for https://www.sbmar.com/articles/custom-yanmar-marine-exhaust-design/

Thanks
Eric

[Eric]

Thanks for the link. I have about 3 inches clearance on STB engine and about 4-5 on Port. I notice a couple of other items that will require some maintenance..

[Eric]

Corey,
thanks for the fast replies, particulary on a Sunday!
1) – Talk to me about what changes I need to make to make it safer. Its been like this since the previous owner isntalled the engines in 2006. You are concerned with water remaining in the fiberglass tube after engines are shutdown and it could flow back into the engine with a little boat rocking? Is there an extension piece that would extend the mixer higher so the anlge is more acute?

2) Its a home brew job. Monitors 4 batteries (V, A and aH), Fridge, Freezer, compressor, Freon, engine temps, 4 bilges. Displays all info and sends to the cloud so I can do analysis. I’m a complete nerd, that’s why I am trying to figure out the easiest way to get boost and pyro monitoring on N2k. Looking at https://www.summitracing.com/parts/vdo-360043/overview/ and a pyro sensor (does it matter how ‘deep’ it protrudes into the exhaust manifold bracket #16?)

3) I’ll install Pyro before the turbo if that makes most sense. I’ll see how easy it is to remove the plug and then tap a 1/8 in it.

Thanks again,
Eric

[Eric]

Tony,
here are better photos of both engines. I thought that since the mufflers are so much lower, the setup would be ok?

[Author]

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