Quote:

However, even today's "ultra" premiums come nowhere near the octane level of the what was available 30 years ago. In those days, octane ratings of 100 were common; today 94 is the best you can get--and the octane level is raised not by lead but by the addition of "aromatics" that may cause problems in older engines.




A different formula was used back then. The "RON" was the standard until a more accurate method was deemed neccesary.
this explains the system and formulas for determining
octane rating.
On another note; turbo or supercharging effectively increases the compression ratio by forcing pressurized air into the cylinders.

Contra todo mal, mezcal; contra todo bien, también