compression ratio vs. octane rating

came up in conversation, trying to figure out what kinda fuel is required at what compression ratios?

of all the common compression ratios available in the big bore kits available what kinda fuel should you excpect to run?

whats the cut off from pump gas to race fuel?

just sumthin ive been pondering on, any ifo would be greatly appreciated

depends somewhat on what motor u are talking about for sure.Cams play a roll as well.
on a kz 1000 u will have trouble with pump gas when u get up near 180psi .So i hear.
i have a 10.25:1 at 160psi,425"lift,260 dur. on pump gas . no trouble.1135cc, and 1327cc's.

the most you should go on pump gas (91) would be 10:1, due to the air cooling and aluminium head, the hotter it gets the more octane your bike will require

my bike makes 200psi (12:1ish) and i used to run 110 but ran into overheating issues when sitting to long at stops

I switched to e-85 (120octane)and it burns cooler and lengthens my riding time, and it smells sweet.

This discussion should be kept to KZs and NOT other bikes. Other bikes have different shaped combustion chambers and the compression ratio effect on octane will be different. The 10.25:1 Wiseco pistons in a KZ are still good on hi-test. After that, you need to start playing with ignition timing and octane boosters or race gas. Folks who used to run 110 octane from Sunoco are OLD bwhahahaha Does anyone else remember the 25 octane ratings you could select on their pumps? I think they only carry three like everyone else these days... The 110 octane could have been from a race gas source I guess so themachine may not be an old guy like me... bwhahaha

I dont know for sure where the cut off is, there are a lot of things that affect the perignition, how efficant it cools after the fire, the plugs and spark from the coils, even the wires can cause problems when you think its fuel.
the e85 stuff is going to run cooler, the combo also makes a bit less power thus less fuel milage.
Most of what you will be dealing with is the BTU of the fuel, the higher the compression ration the more octane is needed to control the burning of the fuel

so is this e85 a good fuel to switch to? does anything need to be changed to run it? is it better with higher compressioon?