What octane do I need?

[first5ny]

My manual says to use a gas with a minimum octane rating of 89 using the AKI method. On a car forum one member said that in the US the octane rating is done by the "RON" method and that an 89 octane rating (AKI) is equal to a 91 octane rating (RON). He said I need to use 91 octane in the US.

I'm confused. I thought that the pumps in the US say that the octane rating is derived at using the AKI method which includes RON in the calculation.

What octane do I need?

 

[Hammer]

The Octane listed on the pumps in the US are derived from R+M/2. In other words, the average of Ron octane and Motor octane.

Hammer

 

[Chris]

You need the lowest octane that does not knock.

 

[first5ny]

I guess my question is: when I see 89 octane on US pumps is that the octane derived at from the AKI method?

I don't want to use the lowest octane that will avoid knocksa and pings since my engine has an anti knock function which prevents knocks at lower octane levels. Just because it doesn't knock doesn't mean its the right octane to use.

 

[Mystic]

My car requires at least 87 Octane but because of the high elevation here in Colorado 85 Octane is acceptable. Question, however-when they reduce the Octane do they also reduce the detergent additive concentration?

 

[LCD]

Just run the lowest octane with a dose of FP and you should be fine.