GermanLook Forums - wrx cooling ideas

The following is how i have done my system.

for the pictures refer to http://vw1302rsi.multiply.com/photos...em_Discription

When I call a coolant pipe or hose the lower radiator something pipe or the such and such upper radiator hose, I am referring to the standard Subaru set up e.g. the hose from the water manifold goes to the top of the radiator in the standard vehicle, it does the same in my car it just goes down then up then along then up, make sense.

I have posted pictures to go with this description, they are on the photo page..

The main coolant pipes are 38mm ID Stainless steel, they run the length of the floor pan, one under each side, they are attached to the floor using exhaust clamps. Looking from the rear of the car the pipe that runs down the left hand side is for the upper radiator hose and of course the other is for the lower radiator hose –Pic’s A and B

The radiator and the fans are from a WRX or a 2L turbo Legacy, the reason for using this radiator is that it hasn’t got a radiator cap on it but it has a top tank bleed, this is connected to a tap that is only used to bleed the system. After removing the spare wheel well, the radiator is mounted vertically, and the radiator is connected to the main coolant pipes by stainless steel cross pipes and moulded hoses –Pic’s C, D and E.

The water manifold has been modified to go backwards towards the flywheel end of the engine and then turns 90 deg to go down behind the head, from here it connects to the main coolant pipe, it also has a pipe attached to it that goes to the header tank, –Pic’s F and G.

The header tank is custom made and has the radiator pressure cap on it, the system is a recovery type and has a Subaru Legacy Turbo overflow bottle mounted under the floor above the left and rear axle, the remote fill point (yellow cap) is mounted below the header tank, just behind the head, The header tank fill point is the highest point in the system –Pic’s H, I and J.

The upper radiator hose is connected from the rear of the main upper coolant pipe (left hand side from the rear of the car) to the modified water manifold by a moulded hose – Pic’s K, L and M.
In these photos you can also see the bottom of the overflow bottle and its remote fill point.

The lower radiator hose is connected from the rear of the main lower coolant pipe (right hand side from the rear of the car) to the thermostat housing by a flexible hose, this is clip out of the way of the exhaust manifold. The thermostat housing/hose neck is from a turbo EJ20 engine and when fitted to the 2.5L it faces backwards towards the flywheel, the thermostat is modified by removing the one-way valve and opening up its hole to 4mm –Pic’s N and O.

The Fans are both two speed but wired to come on at the higher speed and are controlled individually the smaller by the ECU and the larger by a fan switch in the upper coolant cross pipe –Pic P

The radiator is sealed around its sides and top with foam tape and is panelled in alloy in the front , on the top and back, there is a small air dam at the bottom of the radiator that hangs about 50mm lower than the front valance, the bottom edge of the radiator is about 180mm back form the valance.
The air is drawn up between the valance and the air dam and then through the radiator it can not go around the radiator due to the sealing foam, once it has passed through the radiator it is channelled out under the car behind the air dam –Pic’s P, Q and R.

The system bleeds up easy as pipe with the top radiator bleed and the 4-6mm hole in the thermostat, it takes about 10 minutes at idle or 5 minutes on the road to reach an operating temp of about 85 deg C, and just sites at that temp all day long, when it was on the dyno it was peeking at just over 90 deg C after two hours of tuning, so I’m very happy with the system.