what can happen?

[tayznild]

why manifolds need water. cars dont need it. if i move the manifold water hose to the y pipe, what can happen?

 

[81 Checkmate]

Re: what can happen?

For one the explosion factor! with a engine in an enclosed chamber. The water helps keep your manifolds cool so they dont catch anything on fire.
Have you ever seen a dragster go down the strip at night? It has those big blue flames coming out of the exhaust! You have the same thing on your boat!

Your car has a grill and open under the motor so no fumes ever get traped.

Just a thought!

 

[RogersJetboat454]

Re: what can happen?

For one the explosion factor! with a engine in an enclosed chamber. The water helps keep your manifolds cool so they dont catch anything on fire.
Have you ever seen a dragster go down the strip at night? It has those big blue flames coming out of the exhaust! You have the same thing on your boat!

Your car has a grill and open under the motor so no fumes ever get traped.

Just a thought!

On top of that, the air passing under the car and through the radiator keeps the manifolds cooler than if they were in an enclosed space.

To the OP;
If the manifolds didn't need to stay cool, don't you think the OE manufacturers would have eliminated jacketed manifolds a long time ago to save money?

 

[PiratePast40]

Re: what can happen?

One of the products of energy transfer in the internal combustion engine is heat. The heat energy is transferred to the water in the engine and then to the surrounding water. In an automobile, the heat is transferred to the air via the radiatior. You could certainly mount a big ol' radiator in the front of your boat but that's not very practical for everyday use in what we consider a "normal" boat.

As far as moving the water inlet point to the 'Y" pipe, you're allowing the manifolds to get hot enough to melt the rubber. Besides, it's more efficient to start dissipating the heat close to the source. There are applications for dry exhaust systems, especially in race boats. But again, that's not our normal pleasure boat application.

 

[Don S]

Re: what can happen?

IF you was able to run your car engine under a load at 4000 rpm and look under the hood in the dark, the exhaust manifolds would be glowing yellow/orange from the heat.
Now stick that inside an enclosed engine compartment next to wood and fiberglass and gasoline and tell me what you get.
Even if everything was fire proof (which it's not) the heat buildup would be tremendous and you would have some serious vapor lock problems.

 

[tayznild]

Re: what can happen?

Thanks every one . I'm starting to hate inboards...

 

[mkast]

Re: what can happen?

I'm starting to hate inboards...

Understanding the design/function of sterndrive/inboard applications will go a long way to overcoming your hatred.