Re-routing coolant lines for oil cooled turbo. Any reason we can't do this?

[Tamra]

So our BW S200SX is oil cooled. This means we can completely delete the water tank for the turbo. In the manual, it shows using the u-shaped hose to bypass the heater core hose going between #1 (silver pipe from coolant crossover) and #2 in my photo (well, it seems like on the 2.5l engines these are next to each other, and on the 2.0 engines you have to get a different hose.. ours is a 2.5 block and 2.0 heads and it appears everything aside from the block was from a 2.0 engine).

Per my understanding, the #1 is the feedline to the heater core, and #2 is the return line to the waterpump, so then when you loop them together it all returns to the water pump, right? Then, from the waterpump, there is an outgoing waterline to the turbo. So one feed line, one return line, on the right side of the water pump, right?

Since we don't need either of these, can you see any reason not to get rid of the black hard lines in the photo, delete the metal line off of the crossover pipe (#1 in the photo) and plug it, and just loop the two water pump nipples together using the u-shaped line (in blue)?

http://i1374.photobucket.com/albums/ag408/wrx818/Build/photo21_zpsf6b9d789.jpg (http://s1374.photobucket.com/user/wrx818/media/Build/photo21_zpsf6b9d789.jpg.html)

[Tamra]

36114


Looking at this diagram, they are all return lines to the waterpump (no feed lines, all the feeding goes through the engine core). We will have to plug the turbo coolant feed where it comes out of the head. We think we should be good to go with our plan. Let us know if you disagree.

[Tamra]

Nevermind, it seems that the coolant flow through the heater core bypass (the u-shaped hose FFR provides) is what supplies the heated water that opens the thermostat. Without that heated water, the thermostat will not open. The flow of water is from the waterpump into the engine, up into the coolant crossover, out to the heater core, back through the hardline that feeds into the bottom nipple on the water pump, past the thermostat, triggering the sensor to open once warmed up.

[Ironhydroxide]

when I get to building my kit I plan on using something of this sort
http://www.summitracing.com/parts/mez-wn0072?seid=srese1&gclid=CI70jOzgo8ICFYOUfgodjUoANg

installed in the upper radiator hose. this way it acts as a normal thermostat and I don't have to worry about all the crap of heating a thermostat in the low side of the pump and all the detriments that provides.

[xxguitarist]

when I get to building my kit I plan on using something of this sort
http://www.summitracing.com/parts/mez-wn0072?seid=srese1&gclid=CI70jOzgo8ICFYOUfgodjUoANg

installed in the upper radiator hose. this way it acts as a normal thermostat and I don't have to worry about all the crap of heating a thermostat in the low side of the pump and all the detriments that provides.

I think that would work once the thermostat was up to temp, but if you cap the two additional returns to the pump, and are only flowing through the oil cooler (if even that one?) I'm not sure if you'll have good temperature consistency throughout the block coolant on start-up.

The stock system relies on flowing up through the block, into the crossover pipe, and around through heater core into the other side of the pump housing again. When this heats up, then the other half opens.

I'm not sure if without this, there will be any flow through the block & heads, until the thermostat opens.

[tofer9458]

it should still heat up just fine, i believe subaru did the coolant tank to create high point in the cooling system, without it good luck bleeding all the air out of the system using the radiator.
however, you could eliminate alot of those hoses and just run a remote coolant resevior but at that point you didnt gain much