The hot part looks like a nondescript pot.As the name implies, it's supposed to be HOT, taking the exhaust gases of Appia, with temperatures of about 1000C, in contrast to the COLD PART, which deals with a much more gentle temperatures and should stay as cold as possible - to the amount of beneficial oxygen molecules in the injected into the combustion chamber air volume was greater due to the greater density of the air
More power, on the threshold of detonation, well, a lot of different delicacies.
1)the hot part should be hotter to the energy of the Exhaust Gases with high efficiency and spinning the impeller of the turbine.
2) the cold part of the turbine should be as cold as possible.
- keeps the heat inside the turbine increases the heat transfer
- reduces temperature extremes, payasam service life of the turbine
- reduce the temperature in the engine compartment