Remove exhaust cooling

[Mak1]

So... As the headline implies. Has anyone done this or maybe been thinking about it and have some ideas to come up with?
I have a speedster 200 with twin 155hp from 2004.
I have some experience in motorcycles and sportscars and understand that there is a lot of heat coming out through the exhaust system.
However, Im thinking that with the insulating bandage and additional materials of today. A lot of the heat can be transported out of the engine compartment. My thoughts are that if it is possible to remove the cooling (I don’t know) I will have to increase the air in- and outlet of the engine bay.
My thinking is:
1. Remove all the hoses and junk for exhaust/cooling
2. Manufacture stainless steel exhaust manifold and exhaust system. The more “open” I can make it the less heat it will create in engine bay. The downside will be a louder boat. However, I only drive it in the ocean and Therefore it’s not a very big deal, however it must be reasonable. After that, the whole manifold will be bandaged
Thoughts anyone?

 

[tdonoughue]

Interesting idea.

Disclaimer: I don't have a SeaDoo or know anything about its cooling system (other than the basics).

I think my main concern would be the plan to construct the exhaust manifold from SS. SS has a thermal conductivity that is very low (around 8). Aluminum is much better (136). For points of reference, cast iron is about 46; steel 26-37; copper 231 (but certainly cost prohibitive). I would investigate aluminum. I think if you are going to remove the mechanism that basically removes heat from the exhaust, you need something that is going to naturally allow more of that heat to escape the metal and get into the air. I don't think the issue is heat in the engine bay--I think the issue is keeping the heat out of the engine exhaust to keep that from overheating.

That said, working with aluminum is much more difficult (more difficult to weld, softer metal, etc.). But there is a reason heat sinks are made of aluminum. I think basically if you made the exhaust manifold a giant heat sink (with the little fins and all), you may be onto something...

Of course, the risk is if you don't get enough heat dissipation, you will find out by causing catastrophic damage to the engine...

 

[Mak1]

I am so glad to see your answer tdonoughue, Thanks for your reply! I have been writing, the same question in 3 different forums without any reply until now. I have seen many threads with people getting water into the engine or into the engine bay or similar problems due to the cooled exhaust system and I’m thinking, “someone else must have thought about this before, and maybe even tested it...”

However. I think you have a point in the “risk” of using stainless steel. I was thinking about the headers you buy for a sports car with aluminum engine, usually are made of SS.
We have a company, making moulder a for the woodworking industry, I can easily make a prototype in steel. This will cost close to nothing. Then evaluate that for one summer. If it becomes a success, I can use thesame drawing for making a pair in SS or aluminum.

So...How to proceed...? I will go down to the garage this weekend and have a look on it. My thinking is that I will try to make a “typical header” going upwards to get a high point which will prevent water to flow backwards into the engine. From there, try to find shortest way out of the hull.
Question is, do I exit below or above water line. If I can exit far above the water line I can a pretty large hole around the exhaust pipe. This will be good for aspiration and isolation of the pipe. Question is, how loud will it be...? Should I add a small muffler. This creates resistance and heat of course...

more input is welcome ?

 

[Mak1]

Headers which I consider to buy for my car. The engine i aluminium and the headers are SS

 

[mrcleanr6]

Keep in mind that dry exhaust is illegal in a boat. People do it like on the old school jetboats but a ticket is depending on the mood of the marine police. Just a fyi