I want to design a heat exchanger by means of a 2 inch pipe passing inside 65cm diameter diesel exhaust. I want to know the best type of metal that endures the temperatures and the gasses of the exhaust?
Do you know what fuel the diesel uses? If the gases are not too acidic copper might be a good answer. I can't see aluminium being any good - it corrodes too easily and as Johannes says, stainless steel isn't a good conductor.