I still hear all the secret 100mpg carb stories. geez. There's nothing that'll make me stop listening to somebody quicker than a story like this - except maybe for the story of the guy who bought the 200mph Dodge cop car.
Henry smokey Yunick back about '82 DID devise a nice setup using turbo and coolant/exhaust heat transfer to homogenize the fuel mixture and allow for better suspension in the runners, and he DID claim twice the power AND mileage - about 35 MPG on a 151 powered Fiero, but these arent "crazy" numbers. I suspect the rad hose thingy was someones attempt to try to re create this system (which was a LOT more complicated) Anyone with high school should be able to do the math: A gallon of gasoline has about 17,500 BTU of energy available. A USABLE internal combustion engine, ie. one that will pull a vehicle isn't going near 100mpg in real world driving. Hybrids are already approaching the milage limits by using the engine as a constant load device so that the engine is always in theory operating in the center of its inherent efficiency curve.
If there's one thing in all this that's a shame though, it's that there ARE certain "magic" (well, not really magic...) devices that do work (sacrificial anode rad caps come to mind) that may get shunned by some as just another scam because of all the stories.
Jim.