Why install a Wet Manifold?

[tom kane]

As a DIY solution to exhaust problems the choice is yours.Running a Turbo after a water jacketed exhaust manifold,with heat loss is common.You have to accept compromises with Turbos anyway,and install the best option you can get (even a water cooled Turbo if you want it.The choice and variety of configurations is massive in diesel engines.
Is Exhaust Gas Recirulation a good option for emission control?it is an old idea.
ECU settings can be varied for optimum running of motors.
There should be no disadvantages using a metal-shroud/water-jacket exhaust manifold if thermal efficiency is taken into account when designing running gear.

[Carioca]

The reason I brought up this subject is that a friend is about to do a DIY marinisation on a 6-cylinder automotive-type 6 cylinder diesel engine rated at 180 HP/3600rpm.

He doesn´t want to lose any available power. Also, wants to stay away from the (potential!) mess of having fresh or raw water in intimate contact with the exhaust manifold.

I told him to use a water-cooled metal-shroud.
I have seen it done on a 6-cylinder Cummins 6 BTA. Apparently, so far so good.

[FAST FRED]

Many of the newer exhaust wrapping systems will keep a dry exhaust manifold cool enough to not overheat the engine space, or start a fire.

Simplest and most reliable is the wet exhaust manifold that is cooled with a slightly larger sized keel cooler.

This is the choice of commercial boats around the world, cheap quick , low risk , and best of all it doesn't need anything ('cept antifreez in the cooling system) to operate in winter where a sea water system would need service with each shutdown.

While there are fine low drag hi $$$$ keel coolers ,

in Maine, 2, 20ft runs of 1 1/2 pipe works well at very low cost.
Lasts a decade or more if painted.

FAST FRED

[Carioca]

Many thanks Fast Fred. Do you know of web sites that carry exhaust wrapping material ?

[Carioca]

Fast Fred, do not bother with my last request. GOOGLE solve the problem in a FLASH !