Yeah 12:1 on pump gas...& iron heads. Yeah right. That is why we are all doing it........because it works every time.
Every time now I see a post by Newbomb Turk, the needle on my BS meter shakes violently.....
I have had engines with 8.5:1 CR detonate on pump petrol.
There are many factors that can cause detonation, some are 'built in' to the original engine design which limits CR.
Far better to pick a modest CR & be safe; then you are not limiting your ign advance curve [ & losing power ] to try & control detonation.
