Higher octane fuel doesn't have any more power, it just allows the engine to be run at higher compression or advanced timing without the air/fuel mixture pre-igniting (detonating).
That is, if you use higher octane than the car requires you gain absolutely nothing. Individual cars and driving conditions can change the required octane for your specific vehicle. That is, a vehicle operating under a heavy load, or has aged and has carbon deposits built up in the combustion chambers might need higher octane fuel. Also if you have advanced your timing you might need higher octane fuel (this might include any computer chip modifications).
The book calls for 89 AKI (mid grade in your area, this might be 87 at high elevations, or 90/91 in hot climates). I have been able to run 87 with no decrease in performance or economy, in my location and for my driving style. Your book might specify 93 RON, but that is only valid outside the US as it is a different way to measure octane and is equivalent to 89 AKI (in USA). |