Heat , IE thermal energy, is the key to producing any type of power in any type of engine. The greater the conversion from fuel to thermal energy the greater the output. As far as emissions are concerned the hotter the combustion the lower the emissions will be. Not emissions can be eliminated during combustion that is why all the exhaust systems are added to reduce them. Honda had the best emissions reduction systems for years, don know if they still do but they had some real good systems. If you want really low emissions try nitromethane, from personal experence I can tell you it is a real clean burning fuel. just pricy