http://www.hotrod.com/techarticles/engine/hrdp_1009_what_ever_happened_to_smokeys_hot_vapor_engine/index.html
Cliffs:
Smokey developed a 2.5L (151ci) Iron Duke four-cylinder Fiero engine that met all '80s emissions standards (with a carburetor and no computer), made 250 hp and 250 lb-ft of torque (compared with about 90 hp and 125 lb-ft stock), went 0 to 60 mph in 6.5 seconds (stock was 12 to 13 seconds), and managed to get as high as 51 mpg on the highway running 93-octane pump unleaded premium gas (the stocker got about 35 mpg on 87-octane)
To completely vaporize the fuel, Smokey used heat from the water in the engine's cooling system plus exhaust heat to progressively warm the system's induction flow to the required temperature. There was a heat exchanger under the carburetor that used hot engine coolant exiting the motor to warm the mixture to around 200 degrees. The air/fuel charge then flowed through a second-stage generator, an exhaust-driven turbine wrapped with exhaust-gas ducting.
The '80s vapor motor's A/F ratio was well over 20:1.
It was the "not invented here syndrome" rearing its ugly head again. How could a couple of gearhead hot rodders know more than all of Detroit's best engineering talent? By this time, Detroit was committed to the computer, fuel injection, and the catalytic converter. Traditional theory was to get rid of or manage heat; Smokey was channeling heat for improved performance, the exact opposite of conventional engineering science.
For example, a typical small-block Chevy runs reliably at a 1,750-degree F stabilized exhaust temperature. At 2,250 degrees, you're definitely in trouble from engine-destroying detonation. But Ralph says "if you can take it to 2,600 degrees F, you can control the burn rate of the hydrogen molecule in the fuel, the major radical in the gas that's causing detonation.
paraphrasing: How to get from 2250 to 2600 without melting the engine is the big unknown. It's believed that the cam design was the big secret to doing it.
"The time will come when engines will be fully accepted as a heat pump."
A few companies are experimenting again with this. If the cam design was the key to getting over the temp hump, then direct injection, variable cam timing, and precise engine controls could yield some incredible HP-MPG combos.
