Subaru Enthusiasts Car Club of the Sierras - View Single Post

Dean · 2006-06-19, 08:48 AM

OK, this is a gross oversimplification/generalization, but...

Typicaly, you want to run the lowest octane you can that allows the most timing advance without detonation.

On a low compression NA engine, especially at altitude, this is most often 87.

If your owners manual says to use 87, using 91 is most likely to deminish performance.

Octane is basically, the amount of fire retardent in the gas. And you want the minimum amount possible to eliminate knocking.

2006-06-19, 08:48 AM	#12
Dean Señor Cheap Bastarde Real Name: Dean Join Date: May 2003 Location: $99 Tire Store Posts: 9,294 Car: $.04 STI Class: Fast,Cheap & Reliable=STI Deal, did somebody say Deal? Oh, Dean, yeah that's me.	OK, this is a gross oversimplification/generalization, but... Typicaly, you want to run the lowest octane you can that allows the most timing advance without detonation. On a low compression NA engine, especially at altitude, this is most often 87. If your owners manual says to use 87, using 91 is most likely to deminish performance. Octane is basically, the amount of fire retardent in the gas. And you want the minimum amount possible to eliminate knocking. __________________ I am a Commodore PET --- Now get off my lawn you kids...