I have for a while, I have thought about turbo cooling, and some time a go, I asked another member how they cooled their turbos that have water cooling provision. So what I decided to do is to have it's own pumped circuit through the header tank with a thermostat that opens when the water gets to 70 degrees. The thermostat will open a branch off the turbo cooling circuit into the main radiator with a non return valve. Of course what I don't know is whether the pressure in the turbo cooling circuit will be high enough to overcome the pressure in the car's normal engine cooling system. The non return valve will stop any reverse flow of engine cooling water into the turbo cooling circuit.  

Surely it's a closed system... the header tank is under pressure, it's just where any  air rises/bubbles up to. So the pressure before your pump is already the same as at the radiator top pipe. The existing pump and your new pump just encourage sensible circulation.

 

It needs to be remembered that ANY pump creates FLOW and NOT pressure -  It is the resistance to that flow which creates the PRESSURE.

Think of a garden hose, with the tap wide open, the best that you will get, is a large volume of water, but at low pressure.

Now put your thumb over 9/10 of the hose opening, the flow is greatly cut down, but the pressure goes up, as demonstrated by the increased distance that the water will travel, and the pain in keeping your thumb in place!

Even Diesel injection pumps which are often referred to as 'high pressure' pumps only create flow - the injector creates the pressure by offering resistance to that flow.

 

I think that I would try your setup WITHOUT the check valve,(maybe even without the additional thermostat) as I predict that there would not be sufficient pressure differential each side of the valve  to make it open.

In any case, the advantage of air to water, rather than air to air inter-cooling, is that when the engine is cold, the system works in reverse, taking heat from the water to (slightly) warm what could be, too cold air for the given situation.

If all that you wish to do is provide denser air to the engine, an air to air system may be a better bet.

People do become confused by some of the terms used, but inter-cooling, charge cooling and post-cooling are in fact, just alternative names for the same process, it is only the way in which it is achieved that varies.

 

Regards

Thanks for your comments. It's made me think a lot more about what, I have to look out for in terms of the pressure generated in the expansion tank and how water  may then  flow through the turbo and maybe not requiring a pump but I want to get cooler water flowing the turbo and then finding somewhere to cool it. Caretakerplus, you may have misunderstood my original post. My turbo came with a water manifold around the centre bearing area. My aim when plumbing this in, is to reduce under bonnet temperatures. The intercooler is already installed (completely hidden) in the area between the grill and the radiator which I hope will give me a lot denser air into the engine.

Your air-to-air intercooler will certainly give you the best results for what you are looking to achieve.

Thinking about the cooling for the turbo itself, whatever you do is going to add to the under bonnet clutter, but the thought came to me that it may be possible to 'T' into the bottom radiator hose and connect that to the turbo coolant inlet.

Maybe then using a 'swept' 'T' to connect the outlet to the vent pipe which goes to the header tank - The idea of the swept 'T' being to reduce the risk of hot coolant flowing back to the bottom hose via the turbo.

An alternative might be to connect the turbo outlet to a boss fitted into the air space above the normal coolant level in the header tank, there would be no chance then of a back flow.

 

Regards