What type of fuel do you recommend using in the new Challengers? I read through the manual and didn't see a reference to the best type of fuel to use.
I assume 91 octane is best, but maybe not?
I reside in Maryland and I drove my Yukon 320 HP thru the Rockie Mountains an thought I should buy a higher octane fuel,91, Mistake it ran worse. Yukon runs on Regular 87 octane. Colorado regular is 85 .
The higher the altitude above sea level, the lower the octane requirement. Modern computer-controlled engines adjust spark timing and air-fuel ratio to compensate for changes in barometric pressure, and thus the effect of altitude on octane requirement is smaller in these vehicles. "Octane ratings can vary greatly from region to region. For example, the minimum octane rating available in much of the United States is 87 AKI and the highest is 93. In the Rocky Mountain (high altitude) states, 85 octane is the minimum octane and 91 is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere. This directly translates to reduced absolute compression in the cylinder, therefore deterring knock. It is safe to fill up a car with a carburetor that normally takes 87 AKI fuel at sea level with 85 AKI fuel in the mountains, but at sea level the fuel may cause damage to the engine.
