At an elavation of 700 - 1300 ft. would i be able to run a 20cc dome on a lt250r using 93 octane gas or would i have to go higher?

 

From what I’ve read online, you should run 109 minimum octane with a 20cc dome 100 with a 21cc dome and 92 with a 22cc dome.

A few things about it don’t make sense to me though. I have a 22 and a 21cc dome. It would seem to me that 1cc difference would be hard to see and not make a major difference that would require such a jump in octane rating. I can see a major size difference between the 22 and 21 dome, which makes sense for the difference in fuel required but not for the only 1cc size difference. I wonder if the numbers are actually just part numbers and not the actual volume of the chamber. Maybe someone else can explain that too.

I am at sea level and am going to put on my coolhead this afternoon . I’m going to put in the 22cc dome for now and see what happens on 92,89 and 87 octane. If I find that I can run the 22 dome on 87 octane I will likely put in the 21cc dome and run it on 93.