So here is an engine on the dyno at full song. Notice anything interesting about the exhaust system? The engine is tuned for best power, and that means just a hair rich of peak EGT.
 
It has a short life expectancy. Both the engine and the exhaust system.
 
These exhaust systems are .049" and .035" Inconel sheet stock rolled and welded by hand. I have two of them. They are works of art.
 
Notice that the turbo must be supported. Even the Inconel has much reduced strength in this situation.
 
At 900 HP and 28% efficiency how many BTUs are we looking at leaving as waste heat?
 
So if you were to ceramic coat inside and out, and then heat wrap the tubes the heat left in the exhaust gasses would be astounding. These headers are exposed to the airstream in the race car. Not so in the airplane. Even the tip of the exhaust pipe should be turned slightly away from the airframe. The EGT measured at the port will diminish only slightly at the tip of the pipe, if you insulate the pipe. You cannot hold your hand even a foot from these pipes for even a few seconds.
 
Lynn E. Hanover