Either I suck at using google (entirely plausible) or it just cant be explained in plain English. If I increase my compression ratio, at what point do i need to consider raising the octane rating of my fuel, and how do I figure out what octane is right.

Second, I haven't done to much reading on this but can I use F4i pistons in an F4 engine? Thanks for any replies.

 

Getting a definitive answer is going to be tricky.
Here's some of what I found googling "octane rating vs compression ratio"
and "Octane vs Compression Ratio Chart"

Octane rating - Wikipedia, the free encyclopedia

Compression versus Octane chart?

Gasoline FAQ - Part 3 of 4Section - 7. What parameters determine octane requirement?

Daytona Sensors LLC - Tech FAQ Engine Tuning

Classic Inlines - Compression Ratio's

Tip for googling, check the bottom of the search result page for suggestions
on search queries based on other peoples similar searches.

Hope this helps, Ern

 

Hmm those have pretty much all the same info as I was able to find. The reason for my asking is if my compression ratio gets bumped up from 12.0:1 to 12.8:1 or even 13.5:1 what octane will I need to use? Looking at building a second engine for my F4 and want to learn as much as I can before the $$ starts to leave my pockets.

 

13.5 will require premium