I realize this is off topic as well, but perhaps of higher interest.
It pertains to testing of 94UL in a Continental.

http://www.flyingmag.com/piloting/1865/flying-a-big-bore-engine-without-the-
lead.html

One comment in the article near the end I would question is this one:

/"Of course, because 94UL is lower in octane than 100LL, its potential
energy will be lower across the board, regardless of whose engine the
future fuel is being used to power."/

High Octane provides a slower burn rate, but caloric value should be the
same regardless of Octane number.
What is the general consensus on that?

Rolf

ON AVERAGE (as quality does vary with refineries, batches and seasons), 94UL
actually has a slightly HIGHER calorific content than 100LL (if it does not
contain a percentage of ethanol).  The main reason is the higher
concentration of additives in 100LL than in 94UL, additives which brings no
energy to the fuel mix.  However, as 100LL is much more detonation
resistant, it tolerates higher compression and/or boost ratios resulting in
higher overall engine efficiency.

Conclusion:  if an engine can accept low-octane fuel (such as the rotary),
then it will get (slightly, i.e. 1-4%) better specific fuel consumption with
94UL than with 100LL.  If the engine cannot accept low-octane fuel in its
existing definition, then its performance envelope has to be reduced to
accept it.  The quoted statement is fundamentally flawed.

Francois


Are you in Copenhagen? I am curious on what is going on there.

Paul Lamar