Higher octane fuel does not equal more power. Higher octane fuel is simply harder to explode. That means it takes a more powerful spark to actually get it to ignite (which most ignitions are capable of) but is harder to detonate (which is exploding where it's not supposed to, like before the pistons comes back to TDC or in the intake manifold). Some higher compression engines run better on higher octane fuels simply because they could get detonation on lower octanes. For example, a GS-R's B18C1 DOHC VTEC engine. It has around 10 to 1 compression and very aggressive fuel and ignition maps and requires premium fuel. It also has a knock sensor that listens for detonation and will richen the fuel mix and pull some ignition timing out if it hears any. That's why it makes less power on lower octane. Not because the fuel has less potential but because the engine is trying to keep from destroying itself. Seeya.