Mark Dorm said:

> We're not interested in creating heat - we're interested in moving the
> pistons - the heat is really a loss of energy

Well, don't they call it the internal COMBUSTION engine?  The engine is
nothing but a heat pump, so your comment is absurd.  *** Heat is energy! ***
Heat is released during combustion.  The stored energy in gasoline is
released as heat.  Combustion is nothing but accelerated oxidation.  You're
burning fuel.  So you are interested in making heat, it's what moves the
pistons.  I've never heard of a cold explosion.

What you're not interested in is making more heat than your engine can
safely disperse and move away from precious mechanical parts.

All I was saying is that the hotter heads may be explained by a more
complete combustion.  This does not leave enough unburned fuel to cool
things inside the combustion chamber.  So the plug that gives you hotter
heads may actually be better, in strict technical terms, but not better for
your engine.