[Barry_R]

Dynamic compression ratio numbers are interesting and directionally useful - but they're decidedly not the end answer. They are really neither "dynamic, nor "ratios" - just a mathematically derived value for comparative purposes. Only a single piece of the puzzle.

There is nothing in the DCR calculation to account for a well shaped and contoured combustion chamber versus a less effective wedge or hemi. Nothing in the DCR accounts for crevice volume, piston dome shape, quench, low lift valve flow characteristics, exhaust back pressure, or a plethora of other things which will definitely have a significant impact on a running engine's cylinder pressure signature or tendency toward detonation.