I am brand new here and doing a T25 DIY turbo with IC etc on an early 90. It will not be raced but I am just lusting for a little more power. First of all a huge thank you to the DIY FAQ and project threads they answered a lot of questions. I am wondering if the best water supply would be running a line out of the heater and then into the turbo and then back to the water pump pick up. The other set up I have seen is to use the little hoses of the bottom of the thermostat housing but they seem too small to supply all that is needed. What the best route?

 

I would think that the fittings on the turbo would be quite a restriction to the water flowing through the heater core hoses. Since water flow through the heater cool is critical to keeping #4 cylinder cool, restricting it would be bad.

When I spoke with a Garrett rep at the SEMA show, I was told that the main benifit of water-cooling is to prevent coking of the bearings after shut-down. Therefore, it's not the mass flow through the center section that is important, it's the amount of water left there after shut-down. I believe Corky touches on this in his book as well.

 

I was told the same thing.

I tapped my water line where FM suggested at the time, in line with the little hose coming from the thermostat housing, going to the 'mixing manifold' at the inlet to the engine/waterpump.

 

Run the lines from the thermostat. The lines are big enough, so no worries there. They are 5/16" and direction of flow does not matter. I would run the rubber line to an adapter fitting, and then run a stainless line to and from the turbo.
Stephanie

 

Thanks very much. That is great advice and makes sense to me. I will use the thermo line!