I. Had to chime in here as these conversations are as one poster commented are often void of data or evidence to suport claimes often made. I won't be able to offer much as well however as an engineer, one of my studies and research is developing systems to better utilize the internal chemical energy of our available fuels, which have some variences from one station brand to another depending on their blends. No doubt fuel temps can have some effect when introduced to the combustion chamber under appropriate conditions. However its only part ofthe eqation. This vehicle
https://vimeo.com/26947432 is my test be where. I use a 12 j & k type thermal sensors to gather readings at all rpm and to quantify the overall environment. So far it runs on one injector feeding all four cylinders at a factory maping that would generally feed one cylinder.
It can run on both diesel and gasoline. Cold start on diesel is still not perfected and still gathering data for these cold months that are added to the Arduino based prcessors controling valves within the system to help maintain delta Q within areas ofthe system. Ill start a thread on it soon. Fuel temps are just one small part of a larger systm of operations just from the induction side to gain higher efficiency.