Evolution of home made SS exhaust system

[jtybt]

This is just the thru transom jacketed and muffled exhaust.

It was too loud and got water reversion.

These are the components of the second generation with SS riser to prevent water reversion. Didn't work.

This is the finished failed version of SS exhaust

This is a pix of the flapper system that is 26" past the center riser manifold and 3" after the baffeled section and where the raw water is finally allowed to mix with the exhaust.

I don't seem to have a pix of the finished product. Maybe tomorrow.

 

[Bondo]

Re: Evolution of home made SS exhaust system

Ayuh,... Looks pretty Good Charlie,....

You'll want to bolt a rather large, thick piece of millbelt to that shutter....
It looks alot like the 1s I built for my pipes,...
The clattering,+ clanging drove me Nuts, til I added the rubber...

 

[jtybt]

Re: Evolution of home made SS exhaust system

Hey Bill,
Ayuh! The clatter only happens when I'm trolling. I'm trying to call the fishies.


...and yeah, it drives me crazy.

 

[AZSenza]

Re: Evolution of home made SS exhaust system

The water cools the exhaust, with no cooling, those pipes would get H-O-T catch everything on fire, sink the boat, well you get the idea! Not to mention complying with USCG regulations

 

[n2ostroker]

Re: Evolution of home made SS exhaust system

You could do that. It's just full dry exhaust. You jacket the pipe all the way to the thru hull exhaust fitting and run a hose off the jacket to a water outlet thru hull like a bilge outlet type fitting. The down side is its a lot louder and you can't use external or internal rubber flappers. You'd need to have the exhaust high enough out of the water or have a steel baffle/vortex inside the pipe to prevent reversion when stopping.

 

[n2ostroker]

Re: Evolution of home made SS exhaust system

Like this

http://www.youtube.com/watch?v=w2GRoN1IcnQ

 

[Tail_Gunner]

Re: Evolution of home made SS exhaust system

While i did not use stainless but blue silcone hose i just tapped into the hose on the top and routed the water via tubing out the back the water fills the hose with its own pressure and drains out from the top...Reversion will not be a issue with any cam..

 

[jtybt]

Re: Evolution of home made SS exhaust system

The biggest problem was the 4" water jacket didn't allow room for the mounting bolts to the stock center riser. The solution was to start over with a tapered section welded to the 1/2" base.

This is a pix of how each section had to be cut and welded together, both exhaust and water jacket. You can see where the baffled section was sliced and a plate slid in and welded in a pattern that both diverted and lenghtened the exhaust tube and restricted reversion.

The final problem was getting the right drain hole sizes at the end of the water jacket. I had to cut and weld the holes smaller 3 times before I got it right. The water has to hold within the FULL water jacket and not drain out and leave a 'bubble' of hot air at the highest part of the riser section This also created a problem at higher RPM's with more water flow. That was cured by a SS tube welded at the highest point of the riser and one near the end of the
exhaust with a hose running in between. Works great. and the water flow into the exhaust before the tips, quiets the exhaust.

There's a real nice throaty sound without being loud.


You can tell I'm not very good at taking pix.

 

[dr_bowtie]

Re: Evolution of home made SS exhaust system

that just looks very nice...well done..

 

[mylesm260]

Re: Evolution of home made SS exhaust system

The system looks fantastic..

Quick thought though...

It looks like you sectioned a whole bunch of pieces to get you're bends...

Why did you not just start with some mandrel bends?

I'm in the planning stages of putting a gen IV small block into my boat with a mercruiser leg.

PCM (and indmar) are the only companies so far that makes manifolds that will work with that motor. My plan is to use PCM manifolds, and make custom risers to work with the stock mercruiser Y-Pipe, I was planning on starting with a 4" and a 3" SS Mandrel U-bend, and a C+C cut flange.

 

[jtybt]

Re: Evolution of home made SS exhaust system

If you look at my failed exhaust/riser, you will see the mandrel bend both exhaust tube and water jacket. One of the problems was not enuff height. If I knew that from the beginning, I could have put the tapered water jacket section at the base plate so the mounting bolts would have enuff room to go on.

The other problem with mandrel bends is the overlength of the bend wouldn't leave much room to fabricate an effective muffler section.. That's why the two previous muffler section were too loud

The other good thing is I welded the water passages in the manifolf so there's no chance of anti-freeze leaking into the cylinders...and the base of the exhaust is solid 'cept for the exhaust passage so there no chance of raw water getting in the cylinders that way. The last thing that was solved was the water reversion from the raw water mixing with the exhaust gasses right past the stock riser. I fixed that by extending the water jacket the full length of the exhaust system and now the raw water mixes with the exhaust 26" past the manifold but still within the exhaust system to quiet the noise.

So far, it's working as planned.

 

[HT32BSX115]

Re: Evolution of home made SS exhaust system

Nice job! Those welds look pretty nice too!!

I am not completely following you as to why you needed the bypass hose from the top of the riser to further down the "muffler".

Is it to bypass the air that would invariably end up at the top of the bend and subsequently cause a "hot" spot?

Is the tube between the hose connections "dry"?

The other good thing is I welded the water passages in the manifolf so there's no chance of anti-freeze leaking into the cylinders...and the base of the exhaust is solid 'cept for the exhaust passage so there no chance of raw water getting in the cylinders that way.

Yeah....you made a homemade "dryjoint" system! Mercruiser produces an exhaust system like that now for the same reason.....It effectively eliminates the riser gasket and the leaks associated with them.

 

[jtybt]

Re: Evolution of home made SS exhaust system

HT,
Right I had to give a place for the air pocket to escape to and excess water at higher RPM's because I had to restrict out-flow very much like stock riser raw water outlets are sized. Now I know the reason for it...not to clog up so they can sell more risers...