Speedster 200 Exhaust Cooling

[vielster]

What is the point exactly of the "exhaust cooling" mechanism on the boats using the 4-tec? Is it just to pull heat way from the engine, or is there some other point to this that I just don't see?

Also, related question, is there any way to run through-hull exhaust on the 4-tec boats. I think it'd be pretty cool to hear twin 3-bangers runnin wide open. Would also likely free up some weight getting rid of all those mufflers...two per engine seems a bit of a waste.

 

[GregZ]

Exhaust heat

Well go run your car a few miles then grab a hold of the exhaust header or muffler. They are big time hot. Then picture all that heat inside a closed engine compartment times two. That's not gonna be good.

The exhaust system gets hot so nearly all types of boats use water to cool it. In the case of the 4-Tec, the exhaust manifold jacket is water cooled, then water is injected into the exhaust gas stream to cool the exhaust itself. With strictly closed loop cooling you could possibly cool the manifold, but you could not cool the exhaust entering the muffler by injection.

One guy posting on another board had his 4-Tec exhaust cooling get clogged, and it literally roasted all the paint off the muffler/water box. Looked really nasty and dangerous.

Your boat pretty much is through hull exhaust already. If you ski or wakeboard behind your boat you will notice most of the transom is "dry" when underway. The exhaust outlets are not underwater.

Please don't make your boat louder and give the Doos a bad image.

 

[vielster]

Thanks for the explanation...that makes perfect sense, it's not to get the heat out of the engine, but out of the engine compartment.

It's "through hull" now but muffled quite significantly. I don't think being louder would give Doo's a bad image unless it sounds 'tunerific' like a civic with a crappy muffler of course. In that case, I wouldn't want the louder exhaust.