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rustnrot
04-26-2008, 08:52 PM
I want to intercool my 3.8L supercharged V6 marine engine. Luckily, there are automotive aftermarket cores readily available to sandwich between the blower and the intake manifold.

1. Do most marine intercoolers use raw water or a dedicated heat exchanger and ethylene glycol thru the cooler itself to eliminate debris and corrosion?

2. If raw water, is a tap normally made into the output of the raw water pump or is a simple "scoop-in", "dump out" setup pressurized by the movement of the boat sufficient, especially since intercooling should not be needed at standstill or idle? In fact, with real cold lake water it might be detrimental to be pumping cold water thru the intercooler at low speed no boost situations, i.e. condensation.

3. The only off-shelf intercooler cores I have access to are aluminum, however, I virtually never expect to boat in salt water. What are the commercial intercoolers made of?

thanks for any insight...

LKSD
04-27-2008, 10:11 AM
They are also made of aluminum, however some of the upper end ones are made of cupronickel..

They usually use sea water for cooling as it provides the coolest charge.. However use of a strainer is recommended as is back flushing periodically.

Fuel injected engines are less prone to surging or loading up if the water flows thu the intercooler while moving slow or idling.. The carb applications are more sensitive to that where the fuel puddles on the intercooler. Thats why the scoopers work well with those as a rule..

:) Jamie / Lakeside Restorations

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rustnrot
04-27-2008, 03:41 PM
Thanks Jamie, a couple more questions and I should be able to pipe up this system. Engine is EFI so no fuel goes thru the intercooler. Certainly fuel could condense out in a carb app like you suggest. I was thinking of water condensation at idle but that is probably unfounded. It would probably take very cold lake water on a very warm and humid day, an unlikely event.

1. It sounds like I should just go ahead and tap into the pressure side of the sea water pump. I'm guessing about a half inch hose? Normally is the intercooler water run overboard or back into the cooling system and exh manifolds? Upsize the sea water pump?

2. I always run a strainer on the suction side of the sea water pump. Should I run a second "finer" strainer on the pressure side of the pump for the intercooler feed?

3. Put a zinc anode on the intercooler or leave it alone? It is unlikely this boat will ever see saltwater and if it did would be immediately flushed after use.

4. I am not sure of the water pressures involved nor how robust the intercooler is. Do the marine systems you are aware of use any kind of pressure relief valve?

LKSD
04-28-2008, 08:49 AM
Thanks Jamie, a couple more questions and I should be able to pipe up this system. Engine is EFI so no fuel goes thru the intercooler. Certainly fuel could condense out in a carb app like you suggest. I was thinking of water condensation at idle but that is probably unfounded. It would probably take very cold lake water on a very warm and humid day, an unlikely event.

1. It sounds like I should just go ahead and tap into the pressure side of the sea water pump. I'm guessing about a half inch hose? Normally is the intercooler water run overboard or back into the cooling system and exh manifolds? Upsize the sea water pump?

2. I always run a strainer on the suction side of the sea water pump. Should I run a second "finer" strainer on the pressure side of the pump for the intercooler feed?

3. Put a zinc anode on the intercooler or leave it alone? It is unlikely this boat will ever see saltwater and if it did would be immediately flushed after use.

4. I am not sure of the water pressures involved nor how robust the intercooler is. Do the marine systems you are aware of use any kind of pressure relief valve?

Actually even on an efi system fuel can sometimes still go thu the intercooler. It depends on where the injectors are placed.

As far as using a sea water pump tee in thats about how it is done if you go that route. I do use an additional fine mesh strainer before my intercooler..

I dont believe that you can put a zinc in the intercoolers, unless you devise a method of your own.

Also yes you may need a pressure relief valve. If you start getting pressures of over 20-30#s then consider one... You dont want to pop a core or other item..

;) J