Cooling System Capacity
Turbo Mini Forums

Some useful numbers from a recent simulation of a 112kW (150hp) 998 turbo:

Heat loss, per cylinder, to:
Cylinder 3.65kW
Piston 2.15kW
Head 2.45kW

Cylinder head temperature 375 Deg C.

So a total of 33kW is what the cooling system has to take out of the engine and transfer to the radiator and then to the air.

These numbers seem to be proportional to the engine output, so for 200hp add another third on top.

The head is where any cooling system deficiencies will show up. Highest surface temperature and relatively small area.

Next step is to calculate the water temperature rise due to the heat tranfer from the head to the water based on the water jacket area.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

1/3% of energy wasted through water is a usual number. However the std cooling system is quite bad (water routing, bypass, simple thermostat).
Modern race engines took the route of multiple sprayers (I read about up to 6) per piston so that they can keep the simlpe cooling systems and add a good oil cooling. I think this is the good direction after having obstructed some water passages in the block to make water reach cylinder #4 before going up to the head.

Edited by alpa on 16th Jul, 2012.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm