I have done a basic test on my car at idle and have found that the exhaust pipe temperature just hits 100 deg C eg boiling point of water 1050mm away from the exhaust port. Is this a good guide to exhaust gas temperature? Can you compare other engines using this method? I also can hang on the the exhaust pipe for about 1 second at a distance of 2450mm. At the end of the system the pipe is just warm eg you can hold continuously. From other information on another forum the temperature at the exhaust pipe exit will burn you hand and mine does not. PS I am claiming about a 78% increase in mpg. Its been said here in this forum that I might be lucky to get another 5 % in thermal efficiency.