Running With No Muffler

[brit_hunsicker]

Anyone out there removed there muffler and either straight piped it, or on most Nautiques, put a Wye in place of the muffler? Any issues with water back feeding when letting off the throttle from wide open? I have a 98 Air Nautique and was thinking about doing this. Just want to know pros and cons from someone who has done it, or knows more about it.

[NautiqueJeff]

All of the new Super Air Nautiques that come with the factory Surf Pipe have no mufflers from the factory.

[brit_hunsicker]

Interesting. I'm just worried that maybe 1 out of 100 times the back flapper could stick open a little and allow water to shoot thru the exhaust backwards and come up into the manifold backwards if the exhaust has no baffles. I know it's a stretch where the conditions would have to be perfect but sounds like a good way to blow some head gaskets.

[Treybizttu]

Just finished installing the motor in my Pro Air (GT-40) with a Y- Pipe...

Haven't had it on the water yet but it sounds great on the hose.

[Miljack]

my '99 Pro Air had the Python engine which came factory with no mufflers and dual outlet exhausts. It sounded awesome, HOWEVER, once we added a Fresh Air Exhaust on it, the boat was much more enjoyable for a full day on the water. I missed the rumble, but no one else did!
I never had a problem with water coming back up the exhausts, my flappers were intact, and we would surf with that boat, so sometimes heavy and listed...

[Paxdad]

I would certainly entertain doing away with the muffler on my 08 210 with the EX343. The muffler is a PITA to work around and I have an FAE with flapper so I would be set. I don't believe the CAT motors have a muffler either.

[brit_hunsicker]

Okay so I'm pretty convinced on doing the Wye pipe now. Next question is what to use? I'm in the HVAC/Plumbing trade so I was thinking easy enough to pipe it in using PVC. We use schedule 40 for doing furnace flues on a 90%, which has fairly hot flue gas still. Would it be suggested to use something different?

[Paxdad]

If you go this route please post photos. The only draw back I see could possibly be that the material you use would not have some type of Marine industry rating. But this would only be an issue if a loss or damage claim existed and your insurance company questioned the modification. Seems like the CAT motors may have a "Y" that can be purchased. Maybe someone with that motor can post a photo of their engine area for reference.

[Treybizttu]

I got lucky and found a gorgeous welded stainless Y that somebody made specific for a DD GT-40 but I have seen several people do it with fiberglass and/ or "plastic" pipe versions.

[Paxdad]

Just finished installing the motor in my Pro Air (GT-40) with a Y- Pipe...

Haven't had it on the water yet but it sounds great on the hose.

How about a photo of the "Y" pipe you used??

[Treybizttu]

[Paxdad]

Nice "Y" and thanks for the quick photo for reference.

[a0128]

Brit - Check this link (below). Scroll down to the bottom and you will see a Y-Pipe. Consult the chart for the correct IN / OUT dimensions. This should be able to be adapted to your boat. I have not personally used this, but would seriously look at if if I was replacing my muffler.

http://www.centekindustries.com/fittings.html

[brit_hunsicker]

Thanks for the suggestions and photos! So I guess my real question is, does anybody know if PVC will withstand enough to be used as exhaust piping? If so, it's a done deal. I can whip that together in no time. I personally don't see any issues, but somebody out there may disagree.

[vision]

What is the deformation temperature of the PVC? I realize your boat does not have a catalytic convertor. But catalytic convertors usually require temps near or greater than 900- 1000 F. Therefore, the temperature of the gas exiting the manifolds of a typical gasoline engine must be substantial.