Quench = the area of the combustion chamber where the flat piston and the flat part of the head are. That would be the left side shown here, ignore the huge bump on the piston.


Octane

Your 96 is equivalent to 92 here in the States.

US octane is an average of 2 ratings, research octane (RON) and motor octane (MON). If you look at a gas pump in the United States, you will see a yellow sticker that says "octane by R + M / 2" which is the formula for the average. In Europe, they only report the RON.