when you look in the manual, make sure to take note of what scale they use. many manuals use RON (research octane number) and will say something like dont use anything less than 91 RON. the majority of the world uses RON, but, like with the metric system, we have to be different. we use pump octane (or AKI anti knock index), which is an average of RON and MON (motor octane number). MON is usually about 8-10 points lower than RON. so: 91 (RON) + 83 (MON) = 174 174/2 = 87 pump octane