Pseudo science indeed. Cooling the exhaust gas would make it shrink, hence enhancing its travel through the pipes. Ceramic coatings do what the other posters said. The ceramics hold the heat inside the pipe better so the outside stays cooler (important for vehicles with the exhausts in closed areas, like cars) and cools to safe temperatures faster. They will keep the pipes a uniform appearance.
If you think about the volume of gas flowing through the pipes the gas doesn't have enough time to change temperature, no matter what they're made of or coated with.
If you think about the volume of gas flowing through the pipes the gas doesn't have enough time to change temperature, no matter what they're made of or coated with.
