So bear with me please.Okay.So there are multiple factors involved in figuring the overall efficiency of an engine.I already stated that I agree with the basic princaples of thermal dynamics.What I've done a poor job trying to explain though is this.I'm not nessasarily disputing the thermal efficiency factor.But what most people seem to overlook is the efficiency of the combustion itself.If I remember correctly.Around 45% of the exhaust emissions on average are unburned hydrocarbons.Of course this is right out of the cylinder before fresh air is added and the mix is exposed to the high temps created in the catalytic converter to try burning off most of the remaining hydrocarbons.We agree that the average engine has about 30% combustion efficiency because it's true.And I believe the thermal effiency is about the same.Okay.Now consider that thermal efficiency remains nearly the same or slightly better by introducing better materials like ceramic coating on the pistons and sodium filled stainless steel valves for heat resistance as Smokey Eunick did in building his engine.As far as thermal efficiency goes,I believe his engine reached about 38% thermal efficiency.All well within reason by cost effectiveness and thermal laws.Correct?The factor most ignored though is the unburned fuel these engines waste.By creating a better vaporization and burn pattern in the combustion within the cylinder.Smokey acheived somewhere near 70% complete combustion of the fuel.That doesn't in any way contradict the laws of physics now does it?Not when they can get more then 85% + combustion efficiency with modern furnaces.Due to the natural tendancy of cracked oil molecules trying to recombine to their origional long chain state.Which by the way is the reason for varnish deposits left behind by the evaporation of old,stale fuel.With the cracked modern gasoline plus addatives.I don't believe there is any practicle way to achieve the high efficiency seen if furnaces burning fuel that is more in it's pure state.but why do people find it so hard to believe in 70% combustion efficiency.Droplets of fuel,no matter how small,can't burn as efficiently as true fuel vapors.Which is the fundamental reason for the 30 or so % combustion we commonly see today.If you had a source of raw gasoline available.And a good method of mostly vaporizing that fuel in a combustion chamber designed for as little flame pattern obstruction as currantly possible.Shouldn't it then be possible to obtain the same combustion efficiency as a modern furnace?Yes,yes and yes.Now with increased combustion efficiency,there isn't a need to use as much fuel to get the same amount of usable energy.And therefore while you would get an increase in thermal tempratures,they wouldn't be unmanagable if you made the same kinds of changes as were made to Smokey's engine.You don't have to break any thermal laws to get substancial combustion efficiency.With the cracked oil added to modern gas.I don't think it's possible to get more then around 70% efficiency due to the tar/varnish residues that woud be left behind in both the fuel system and combustion chamber.That would create as much as,or more problems then the partially burned hydrocarbons now commonly left behind as carbon buildup.I'm sorry if I offended anyone earlier.But I got quite frustrated by being ridiculed like some kind of gullible sucker who falls for the most likely impossible pipe dreams being sold to the unwary public.
It's just that I know first hand on the one fuel system that does work.And he never got his patent.He drove the old truck for many thousands of miles with only two changes made.The rear end gearing.And the carburator he designed.And averaged slightly better then 100mpg.He the took the engine apart to inspect for damage because of his extreemly lean fuel mixture.No where near the commonly accepted absolute of 13.5:1 -14.5:1.and when he knew it would work he applied for a patent.Never did get a reply from the patent office.Instead he got a vague but threatening letter from one of the big three auto makers(no way will I say who) on a day I was helping him and his family do some recarpeting and painting in their house.I know this one from first hand experience and can guarantee it's not a friend of a friend urban legand.The other one I know of is second party,who I trust the source.

I hope with the way I explained the seperate aspects to be considered that are involved in the seperate factors of efficiency have shown you the practicle,and very possible gains that can be made to modern engines without extreem re-engineering needed.It's entirely possible to greatly increase combustion efficiency,without much altering to thermal efficiency in any way.
And I'm sorry this is long,but if you've read it word for word,you should be able to see that it's something that can,and has been done.There are other set ups that have gotten short term coverage in the media,and the inventors claim consperisie.There's sometimes worked also,but not without engine damage because their systems create 90 some percent vaporization of the fuel.Leaving tar/varnish residues that destroy their engines.These are the examples held out to the public as proof all such systems are impossible.These guys didn't do enough research as to what the limits are for vaporizing modern fuel,and paid the price with their reputations and dignaty.I hope you now understand why it's possible to build super high efficiency engines.And why the systems that failed were so easily used to confuse the public about the viability of this very real technology.