Water tank on the engine

[RetroRacing]

Can you not just plumb the water line from the turbo to the inlet on the water manifold and get rid of the tank if you have one off the rad?

[JeromeS13]

That tank is the highest point in the water cooling system. You need it in order to properly bleed the cooling system.

[RetroRacing]

So as long as we put a bleed in that hose, we are good?

[Bob_n_Cincy]

So as long as we put a bleed in that hose, we are good?
In an overheat situation the steam will accumulate at the highest point. You want your pressure release radiator cap at the highest point to release the steam into the overflow tank. The cooler water in the overflow tank will condense the steam back to liquid.
If the radiator cap is not at the highest point, I will just puke out liquid into the overflow tank and then onto the road while your engine fills with super heated steam. I even moved my tank higher for better functionality.
Bob

44068

[RetroRacing]

So a high temp pressure relief valve, in line to a catch tank, set at a pressure just under that of the rad cap should do it, much lighter and takes up no room. Thoughts?

[Bob_n_Cincy]

So a high temp pressure relief valve, in line to a catch tank, set at a pressure just under that of the rad cap should do it, much lighter and takes up no room. Thoughts?
The reason for the DEGAS tank is so bubbles will get collected in the tank. If you just have a hose, the bubbles will get flushed back into the engine.
Bob

[RetroRacing]

Odd, never had one of those before, thanks.

[Scargo]

So a high temp pressure relief valve, in line to a catch tank, set at a pressure just under that of the rad cap should do it, much lighter and takes up no room. Thoughts?
high temp pressure relief valve? You mean a radiator cap? Subaru uses a higher pressure cap on the radiator so the expansion tank (Subaru calls it a water tank) will release first. About 1.3 bar or 19 PSI on the radiator and about 1.08 bar or 16 PSI on the tank. I went with both being 19. You can get 25-30 PSI caps if you want.

[mikeb75]

Also, the upper coolant tank is used during cool-down of the turbo post engine shut off. Having a reservoir of coolant above the turbo allowed gravity/"convection" flow post engine run. A lot of questions used to be asked in the WRX forums about adding an after-market turbo-timer and because of the upper cooant tank it was considered pointless.

For a track only car where you are mindful of proper cool down procedures, I think you could argue against the upper tank - with respect to the other degas and bleeding procedures.

[Hindsight]

I built a larger tank that I mounted to the frame above the engine. The higher mount point ensures proper bleeding and the tank is large enough to act as an expansion tank - so the overflow really isn't needed (though I still have it currently).

[RetroRacing]

We pu the tank in, not worth the weight savings to chance it.