Posted for Walter Atkinson <walter@advancedpilot.com>:

 Dennis:
 
 Shannon almost certainly experienced a pre-ignition event.  The vast majority
of pre-ignition events are the result of failed spark plugs.  A very common
cause of failed spark plug ceramics is detonation.  Detonation is more of a
problem when the IAT is high.  Superchargers without intercoolers result in
higher IATs and a narrowing of the detonation margin.  If I remember
correctly, Shannon had a direct-drive supercharger without an intercooler.
 
 You may apply the transitive property to the above scientific facts and draw
your own conclusions as to probability.  The data downloads tell the data
story.  Evaluation of that data results in conclusions with higher
probability.
 
 Walter