As far as I know, the reason isooctane is better than octane in gasoline engines is because the octane is more prone to ignition by pressure. This makes it ignite when it is not supposed to, which damages the engine.
Isooctane, however, is somehow less prone to this. Why is that? Why is isooctane "more resistant to the potential of ignition incited by pressure"? How are the higher number of ligands involved in this?