Ski Nautique Y-pipe exhaust

As part of the rebuilding process, I am getting rid of the inverta-flo and installing a y-pipe, straight through exhaust system. I know it's not very popular with most of the CCF folks, but let's face it, we all know I'm not your conventional CCF thinking guy.    

Anyway, as such it's not an incredibly common topic. I've done my thread searching and read what there is out there and until recently I figured it was fairly straight forward. But something came up in a Fish Nautique thread recently that got me thinking so I thought I'd ask the group to get some input from those who may know a bit more. The question is if I need to be concerned about water reversion with no muffler or inverta-flo and the stock GT-40 risers?    I'm thinking that the exhaust is well above the water line so I should be good, but a little more input would be appreciated.

Thanks    

Thanks Chris. The boat had a flapper when I bought it. But I haven't inspected it very well, I may need to replace it.

Riding around in the back seat of a ski boat is a crummy ride with or without muffler(s)

gt40KS wrote: As part of the rebuilding process, I am getting rid of the inverta-flo and installing a y-pipe, straight through exhaust system. I know it's not very popular with most of the CCF folks, but let's face it, we all know I'm not your conventional CCF thinking guy.     Anyway, as such it's not an incredibly common topic.

Its not that uncommon at one point I am pretty sure the boat dr was selling a kit at my correct craft parts and race city marine also installed one or two IIRC.    Search the older posts and you will probably find a picture, or give the boat dr a call. Keeping a flapper is not a bad idea.

I am currently working on a pair of v hull boats both with log exhaust manifolds and no mufflers. I am heavily counting on my flappers to prevent reversion.

Reports of logs being susceptible to reversion (even combined with no mufflers or flaps) seem a bit exaggerated... otherwise, I’m not sure how so many of us with older boats configured that way have escaped this reversion epidemic for so long.

I wouldn't be too concerned in flat bottom boats where the engine is higher up off the water.

Someone like Gary or Ken might be able to find the spacers used even on PCM pyramid manifolds on the Fish.

Yes.

I still have logs and straight pipes and no problemo.

If you're elbows are significantly closer to the waterline than they are in a flat bottom, why not get some proper elbows or PCM manifolds and avoid all that pain when your weekend suddenly turns to saving your engine because it filled up with water?

Then you have plenty of time to have those cool looking logs.

I have a feeling this is more an urban legend,does anyone have actual experience getting water in? Someone somewhere probably had a problem with a high overlap cam and over the transom exhausts,some other guys had trouble with big sport fishing boats backing down when fighting fish and then PCM's marketing dept who would sell an engine for any type boat said that their pyramid style exhaust were better than the logs for that reason. We just don't back up hard,we spend most our time going forward.

TRBenj wrote: . All that hull allows the a v-hull to float higher- the Bfn doesn’t dunk the chine by much, whereas the small flat bottoms float with the chine nearly a foot below the surface.

That's how photos of both boats look to me.

What about the noise levels from lack of mufflers?

Just an FYI
I literally just did this conversion on my 89 using a Centek y-pipe. I fired it up for the first time yesterday and the sound difference is NO where near what I was expecting. At an idle sitting on the trailer it honestly would be hard to tell a difference, it is ever so slightly louder but more just sounds a bit different. At WFO it could be a completely different ball game but I won't know that for about a month yet as I'm replacing my interior.
My buddy's got an 88 SN and his on the trailer is still much louder than mine at an idle, and sounds better as well. My boat slightly edges his out performance wise but man the 88 and older Nautiques sure do sound perfect lol.

I'll try to get a sound clip next chance I get.