Gas mileage with ethanol free vs 10% ethanol

[MikeInNH]

@thegreendrag0n

yet on 91 it gives some extra power output (on high RPMs only) and lesser consumption (unless you get too inspired with zoom-zoom).

Higher Octane does NOT mean more power. All it means is higher octane gives premium gas greater resistance to early fuel ignition, which can result in potential damage.

@thegreendrag0n

We can debate if it retards timing for 87 or advances it for 91, but does it really matter?

Actually yes. If you have an engine designed to run on 87 Octane then using 91 octane will NOT advance ignition timing.

@thegreendrag0n

Nissan clearly states 87 as required gas

But then you added this. Which I’ve seen before on my 98 Pathfinder. It means the engine is designed to run on 91 octane. It has a knock sensor to retard timing so engine won’t be harmed if you do use 87 octane.

@thegreendrag0n

but has a note “for the best performance use 91” in both manual and on gas door