Replacing muffler with Y pipe on 97 Nautique

I just finished replacing my muffler with a Y pipe.

Here's the background. A few weeks ago we almost swamped the boat when the muffler started leaking due to a crack in the bottom caused by rubbing on the hull. Anyone with a low profile 2 into 1 muffler under the floor should make sure the rubber pads are still in place to keep this from happening. For me it was too late.

I ordered a Centek fiberglass Y pipe 3 1/2 into 4 and 4 1/2 feet of corrugated hose from Matt at Race City Marine. Checked out with no leaks. I'll post some pics tomorrow. I'm pretty sure I could have gotten by with 4 feet as I had about 6" left over.

Anyone concerned about too much noise without a muffler, don't worry. There's a little more rumble at idle but I really did not notice much difference when cruising. The fiberglass down pipes and all that rubber hose must act as mufflers.

-Phil

Phil
Glad it all came together for u! Looking forward to the pictures ! Let me know if I can help

Matt

Here's what it looks like. Pretty clean and simple install.

I zip tied one of the rubber pads from the old muffler around the Y pipe to make sure it can't rub on the hull.

Once I got this done, I noticed trans fluid in the bilge - always something! Since I had the floor and doghouse out, it was easy to figure out the source of the leak - a bad trans cooling line - got that fixed and I'm back on the water.

Skiing behind the boat, I notice it is a bit louder but not offensive. Makes it seem like I'm going a few MPH faster!

looks good...

but how is the rumble when idling on cruising at 1500-2000 rpm for the ones seating in the backseat?
is it tolereable? i wonder for the small kids...

Nice job and "rumble" is always good!

Good work Phil! Now get that thing out to Diamondhead and lets get you through the course! Then you can convince the rest of my family to get a 97!

Nice and clean modification, Phil.
I miss the V8 sound of my previous '69 Boesch
So consider it for my 5.8 HO BFN.
Did you notice any change in performance?

I bought the Y pipe through Race City Marine. They did a drop ship from Centek so I could get it quickly. Sorry I don't know about the 2000 Air Nautique.

I can't say if the performance changed, I was already under-propped and the boat would turn 5100 RPM at about 45 MPH. A louder boat or car always feels faster though!

To do this to a 95 sn, do I need to get the exhaust tubes for a 96-97:


Tubes


To make my mod look like yours? Or can I run a long 3.5" exhaust tube from the risers to the y-pipe?

No, you dont *need* the exhaust tubes, you can run straight hose like this '90. The tubes might make it a little easier though.

Keith, we use a lot of what we call 'softeners' at work so we can chain down large machined pieces for transport. I'm not exactly sure where they come from, but they appear to be 1/4 to 3/8 in thick rubber with a layer of cloth in the middle, that I believe is some sort of conveyor belt. How big of a piece would you need?   I may have some extras laying around most are about 3 x 6 rectangles.

Keith,
I agree with Tim. Through the years I've gotten plenty of rubber sheet from McMaster. One thing I do recommend if you go with the adhesive back is to put a coat on solvent based contact cement on the muffler before sticking the rubber on. Trim the rubber to smaller pieces to protect only the areas that rub on the hull. The smaller pieces will conform to a irregular surface better and will stick better.

The Buna-N is a good choice for the oily bilge.

Hi,I want this setup on my 89. I get the Y pipe and the rubber hose. But what did you use to get from the exhaust manifold down to the rubber hose? It looks like fiberglass.

Strega51 wrote: Hi,I want this setup on my 89. I get the Y pipe and the rubber hose. But what did you use to get from the exhaust manifold down to the rubber hose? It looks like fiberglass.

These are from 96-97 models originally equipped with the hull hugger muffler:

http://www.nautiqueparts.com/exhausttubesmufflers1996-1997nautiques.aspx