Octane question (MB126)
I am looking at my owners manual from my 1983 380 SEL and deciding what is the correct fuel (octane). The manual reads:
"Unleaded gasoline: Average Octane of Research and Motor 87 (RON of 91).
What does this mean? should I use 87 or 91 octane? and what does "RON" stand for? Why the two different numbers?