RB25 turbo coolant OUT to heater core IN

Hey, guys!

I'm swapping an RB into an MX5, and I wonder where I should plumb the coolant that's coming out of the turbo.

I was thinking about it for a while, and the most comfortable solution would be to just plumb it to the inner heater core, and from there to the water in, behind the thermostat.

Since I am running a Greddy manifold, there is no coolant channel on it, whereas on the stock, you would plumb it there, where it can flow to the radiator.

I bought the engine without the heat exchanger, with the heater core "plugs" on the block welded shut, and I don't have the water lines that were supposed to run there either.

Well, I can open them and run a new line, and since I am planning to use the heater core in the Miata, I have to run one anyway.

I know that you would want to plumb the turbo out line to the radiator, and with this setup, technically that coolant would only see the radiator when the thermostat is open; otherwise only the water pump would circulate it, and of course only when the engine is running.

I could technically run it to the rad, but that would double the lines I have to make, and it would be ugly if I were to run them at the front of the engine.

I wonder if anyone ever did this.

Would it disturb the flow of water in the turbo? Since the heater core lines are thicker than the turbo lines, and the coolant coming out of the turbo would be hotter and physically higher than the heater core connection, plus it would be just a simple Y connection.

Also, my turbo is higher than the rad, and there is no way to go around it. Technically the highest point of the reservoir is higher than the turbo, but that water would only see that when the thermostat is open. Technically, I could run an extra tank next to the turbo, but that would complicate the setup again.

So I wonder if there would be any significant overheating issues after I stopped the engine, and any flow disturb. (Technically the thermostat would still be open for a while so it could circulate but yeah...)

So... any experiences? Please.

For the sake of visual people, that is what I am talking about.. (Technically, the water out is on the wrong side but the point is there.

There is a nice loop there with the turbo on the highest spot. I wonder if there would be a disruption in the flow and what would happen when I shut the car off. The coolant would flow to the turbo to boil there, or would there be some circulation to the outside since the reservoir is on the highest spot?