Converting motorcycle engine to "Steam Engine"
 

I suggest you first read this topic:
https://www.gassavers.org/forum_topic/bmw_turbosteamer_waste_heat_recovery.html

And here is a guy who converted a 4-cycle 2 cylindered motorcycle engine to run on steam:
https://www.steamengine.com.au/steam/models/orv/

Did you understand what i mean ? :)

What do you think about the idea of harnessing exhaust heat by wrapping flexible copper pipes around exhaust pipe and produce steam to run a similar steam engine that this guy has done ?

Maybe this small steam engine can be run to power another alternator and the electricity generated can be used to produce hydrogen and oxygen by electrolysis in another seperate container ?

There wouldnt be any space in engine compartment but i think the steam engine (and its other related gadgets) can be put to the luggage compartment.

And what about the steam that leaves the steam engine ? should it go to the air or can it be recycled by using another car radiator (maybe placed underneath of the car) to make it condense ?

Quote:What do you think
 

i think thats, though well thought out, a total waste of time. u wont gain anything with all the weight u add. if u do gain somthing it wont be practical though. i mean whoses going to give up there trunk space for 1-3 more mpg. IMO not worth it.

Combined cycle
 

Many new power plants use waste heat to generate power. It's called "combined cycle": A combustion turbine generates power, and the hot gas from the turbine is used to make steam, which powers a separate steam turbine. Big combined cycle power plants are about 50% efficient, which is much better than the 40% efficiency of a recuperated brayton or rankine cycle turbine.

So, energy efficiecy IS possible using waste heat and a steam engine. The unfortunate fact for AUTOMOBILE steam engines is that you need about 5 square feet of boiler surface area per horsepower. And if you don't want to carry hundreds of pounds of water on board, additional heat exchangers to condense the steam engine exhaust are needed. So your steam-augmented car could wind up as heavy as a locomotive.

Here's a link to a wondeful website that sells small boilers and steam engines for boats: https://www.steamboating.net

The engines could be adapted for cars. I'd love to see someone build one using exhaust heat.

At least BMW managed to make
 

At least BMW managed to make its existing 1.8Lt engine %15 more efficient for a 100kg =~200pounds extra weight.

About the steamboating.net: The smallest 2HP steam engine is 2750$

Maybe there really exists a reasonable price range for an enthusiast to convert an existing motorcycle engine and harness the waste heat as efficient as possible.

From my point of view: Spending 500-1000$ for this project for a maximum %5 gain would be wonderful.
But before spending money we shall foresee every technical aspect of this project and effectively predict what may go wrong or does not work or simply "dangerous". I must gather more data about this idea.

You can make steam from the exhaust manifold and this splits into wet steam and becomes hydrogen and oxygen at 1000 degrees Celsius, that is a lower temperature than the TDC of almost all piston engines when they are fully warmed up.