I see what you are saying now.. With the way that the SR20DET turbo water lines are routed you basically bypass the radiator and recirculate the hot water from the turbo right back to where it was first gotten from.. It would almost seem that the best place to tap the coolant line for the turbo is from the inlet neck above the alternator and return it to the Tstat housing. This way you get the coolest water from the radiator to the turbo directly and return the "hot" water from the turbo right to the radiator without running it through the engine again. I dont know if this would work however - if the pressures/or whatever recirculates the water would give enough water flow through the turbo- meaning would it still flow water even though this was before the water pump and not after it.You guys are worrying about this too much, IMO. This effort, as I said earlier, is better spent eliminating the HOT WATER RECIRCULATION going on with the small hardline on the back of the engine. Look at it: hot water leaves the head, travels to the T-stat, then goes into the "cold" side input from the radiator and back into the water pump to be circulated throughout the engine. Horrible.
and looking at the FSM, the coolant goes from the radiator to the WP thru the cylinder head to the turbo to the engine block.Additionally you want the coolant to flow through the motor BEFORE it hits the turbo. The coolant leaving the motor is still cooler than the CHRA and as such will do it's job. If the the coolant went through the turbo first and then the motor you would be creating a larger issue.
Ideally you could run a separate heat exchanger and run the coolant line through that before the turbo if you wanted to get nuts with this, however I don't believe that is necessary with proper cooling upgrades.
In all I believe a swirl pot would provide much more benefit than these modifications.
In that case u can always upgrade ur thermostat to open at lower temp, that way its always flowing thru the turbo.The only reason I can think that on the DET motors the turbo is plummed the way it is, is that by tapping into the block the water is constantly flowing through the turbo even though the T-stat is closed (recirculates through the engine block) and receives the highest water flow. It would seem that by tapping into the TB lines the water does not get much flow until the T-stat opens. If this is true, the turbo would actually run much hotter because it has very low or no FLOW through it at all until the T-stat opens.
Can someone please post a picture of where the turbo gets its water supply in the back of the block?