Hull thru exhaust setup question.....frustrated!

[mavcar38]

Im installing a captains call exhaust on my 98 maxum 5.7 alpha one drive. The holes for the tips were drilled exactly to the specs from corsa. I cant go any lower or the flange wont bite for the tips and it will be too far low. The problem Im having is with the diverters and exhaust hose connecting to the tips in the transom. Everyone seems to say they need to point down to the tips. Mine are level or may have just a slight degree pointing downward and the exhaust hose from the diverter to the tip is actually elevated a little. The tips have anti surge valves and flappers, and I have three inch blocks under my risers. What are the chances that water will get in my motor. I can always switch it to stock if I have do with the valve solenoid. Im not understanding how water can get into the motor when it comes out the exhaust anyways and settles back down when the engine is shut off. Id appreciate any help. Thanks much!
Jeff

 

[a70eliminator]

Re: Hull thru exhaust setup question.....frustrated!

Well I can't help much with the geometry of your set up but I can offer some insight on how water can into your engine, this is only from hearsay but if you chop the throttle while on plane that big wall of water can overcome your exhaust stall out your engine and fill the chambers with water, but thats only if you do dumb stuff, I saw (heard) a through transom V8 on the lake Sunday it sounded really strong but I thionk it would get old after a while, I like stealth too, my 351 is so quiet sometimes it's hard to hear if it's even running, but it sure does honk when you hit the throttle.

 

[jerryjerry05]

Re: Hull thru exhaust setup question.....frustrated!

If you have flappers in the exhaust tube then that is supposed to stop the water from going back into the exhaust. If you are really worried they sell a flapper that fits on the end of the exhaust tube.The tube needs to be square cut not angled
If you look at the end of your riser the exhaust comes out the center,The water comes out around the exhaust cooling the manifold,that is where the two mix.If water is drawn back into the motor past that point then damage can occour.
Take some pics and post.Jerry

 

[John_S]

Re: Hull thru exhaust setup question.....frustrated!

Mine are level or may have just a slight degree pointing downward and the exhaust hose from the diverter to the tip is actually elevated a little. Jeff

If this is when the boat is at rest in the water, then you certainly may have a problem when a bunch of people are sitting in the bow. The angle may be toward the exhaust elbow then.

It sounds like some water can accumlate before the tip. You shut the engine down to anchor in a cove. People sit on the bow, etc, water runs toward elbow. Depending on the amount, it may end up down the exhaust and into a cyl with an open valve. Doesn't take much to hydrolock.

 

[Coors]

Re: Hull thru exhaust setup question.....frustrated!

I have a 9" rise from the thru-hauls, internal and external flappers, and am still paranoid.

 

[mavcar38]

Re: Hull thru exhaust setup question.....frustrated!

Thanks guys for all the help and responses. I talked to Corsa today and they are going to fab me some other tips. They are going to angle the connectioni inside the transom.. Here is a picture(s) of what I have......