Originally Posted by Que89YJ
Higher octane will reduce knock. The fact you are running 100 mph makes me think that things are not stock somehow. Did you check your codes? If you move the sensor to a cooker temp with the engine running hotter it will run a more advanced curve. I think out is the opposite of what you want to do.
You are correct in that the advance curve will be affected. To the positive side. I am suspecting that a little additional fuel MAY over ride the slight timing advance relocating the IAT will give. If not the mod is easily reverse-able.
Higher octane fuel is NOT harder to burn. It simply burns at a slower rate (slower flame front) as the octane level goes up. Depending on the additive package is MAY run cooler also but that is a wide generic statement. Cylinder pressure can be that of compression but also timing. Both ignition and valve. Many of today's modern engines run a high(er) compression but still get away with 87 octane fuel. There are way to many factors to consider then what an internet forum is worth.