Hey Ran, Up here in Canadacon (the big village), We basically have the standard 87, the mid range 89, or the premium 91... What you will need depends on a few parameters... Ambient air temperature, timing advance, and boost parameters... You know that I'm running 91, @ 14 deg BTDC and 7 PSI above ambient atmospheric...but, If what you want to do is run the cheaper 87....as the ambient temperature increases, you will need to reduce you're timing advance. From 7 to 6, or so... You'll do better in the winter, or just ad an additional cooling factor to the standard truck set-up... Either, or, It all adds up to the fuel grade... Octane costs cash...$$$ ...
