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Turndowns and water reversion?

I'm planning on putting exhaust turndowns on my 29' Fever 525 and am just curious if water reversion up the pipe is a concern when slowing down?

Had same question! I guess its not a problem but still curious!

Quote:

Originally Posted by River Ratt (Post 4239605)

I'm planning on putting exhaust turndowns on my 29' Fever 525 and am just curious if water reversion up the pipe is a concern when slowing down?

Not sure turndowns are such a good idea with 525's. How long are your tailpipes before they exit? I just had major reversion issues with 525's and Silent Choice..

I just looked at some pics (boats in storage) and it looks like from the header collector to the transom the pipes are probably 16" - 18" and they probably stick out 2" outside. Definitely not using silent choice.

I have read that they sometimes use a weep hole on the underside of the turndown pipes to prevent the siphon effect from bringing water back up the pipe. If that is what you are concerned about, I don't think it is that much of a problem, but I don't have first hand experience with the turndowns. If you are concerned about water coming up the pipes when backing up or something similar, I think the internal flappers should control that.

we put a hole on the top of each pipe to break the vacuum.motors were KE725's in and OL.

A hole? You must have exhaust fumes and water coming out of there while running for sure? Don't you'?

I think he means a hole in the top of the turndown pipe. Doesn't take much to break the vacuum.

Still dont think it's a good idea, anything that pushes water back up is no good with 525's...

Quote:

Originally Posted by donzi matt (Post 4240325)

I think he means a hole in the top of the turndown pipe. Doesn't take much to break the vacuum.

exactly

Merc does a similar deal with their underwater exhausted european big hp motors.

Amazing what a tiny unnoticable hole does to someone's straw. LOl.

I double checked where i saw them, and Mercruiser actually has a kit called: X-haust Noise Reducer Kit

http://www.mercuryracing.com/sterndr...noise-reducer/

Quote:

THE PROCESS
X-haust features a custom Y-Pipe which combines the two banks of exhaust from each engine into a single exhaust tube. The single tube exhaust outlet per engine provides the transom space needed for the transom mounted X-haust muffler. Back pressure is minimal, resulting in insignificant power loss.
An integrated idle relief tube routes some exhaust through the boat above the waterline, providing a necessary vacuum break and a little rumble when operating off plane.
The transom-mounted muffler is completely submerged when the boat is at rest. The muffler outlet directs engine exhaust down and back toward the transom further reducing noise.

X-haust is available for use with the HP600 SCi, fitted with an Integrated Transom System (ITS) Bravo One XR drive model or optional dry-sump NXT¹® drive, EU662 SCi and HP700 SCi sterndrive engine packages fitted with the dry-sump NXT¹® drive. Stage 1 and Stage 2 configurations are available for single or twin engine applications in both side-by-side and staggered installations.