egg https://www.wired.com/2012/08/fuel-economy-vs-mass/
Yeah, so reducing the mass of the Mirage won’t change its engine or its aerodynamics.
I will absolutely experiment with fuels, but past experience strongly suggests that 98 octane fuel won’t improve the fuel economy of a SOHC 4G15.
It is a common myth that more octane magically makes more power and/or improves economy. Octane ratings are ONLY about detonation resistance - if it doesn’t want to detonate on 91, then giving it more octane does nothing for you.
The whole topic is confused by ECUs being programmed to use knock sensing to alter fuel and ignition timing, but the fundamental point remains: more octane only helps if the motor can use it. As I said, I will definitely experiment, but I seriously doubt that a 1990s Mitsubishi commuter car will benefit from more than 91 octane dishwater.
This statement regularly outrages people on various forums and FB pages, but has never been refuted:
Use the lowest octane fuel that reliably avoids detonation.
