One of the biggest problems with chilling the fuel is volume... sometimes you are only pulling a few CC and the next minute you are pulling hundreds of CC! This would as a result vary the temperature of the fuel going to engine greatly.
If I just chilled the fuel rails, I create a consistent chill and at the same time maintain an even temperature amongst all fuel injectors. The fuel injected engines in Vipers and Dakotas (no relation to cubic inches) have no return fuel line. This causes the fuel that reaches the passenger's side of the engine to be hotter... which can cause pre detonation, reducing the overall efficiency and losing HP.
I have this system working, during the summer months, you can really feel the difference when the engine is hot and the system is off. The truck feels sluggish to start and rev up. I have dyno charts on my webpage and more indepth discussion.
As far as donor Peltier's, I have an 80W and two Danger Den Maze 4's at home. I putting them together with my special Epoxy (to protect the fragile electrical connectors) and RTV Silicone treatment. What water vapor???
Thanks, keep up the discussion, ideas are hard to come by.