Posted by HornsFan on March 09, 19100 at 07:05:16:
In Reply to: High Octane......worth the extra $$$?? posted by Graembo on March 06, 19100 at 22:56:19:
Common misconception among the "average Joe":
Higher Octane rating = higher quality
NOT THE CASE!!!!
Your engine's compression ratio (that's the compression in the combustion chamber)will determine the best octane rating for your engine. Performance engines, or any engine that attempts to squeeze the maximum amount of horsepower for a given cylinder displacement will increase the compression ratio on their engines and therefore require a higher octane rating to prevent premature ignition or "knock". A higher octane fuel is actually more resistant to "knock" or ignite before the spark plug fires because it is not as volitile as a lower octane fuel. That, folks, is the only difference in octane rating. Granted, some oil companies fuels are just "better" all around and some even add detergents to the higher octane fuels to keep the engine clean, but this has nothing to do with the fuel's flash points. Octane is not a measure of quality, only a measure of what compression ratio the fuel can withstand before it will combust without the benefit of fire from a spark plug. A simple response to your question is this. The manufacture knows a whole hell of a lot more about the fuel requirement than you, or anyone on the forum does. Listen to them. Open that book called an owner's manual and use the octane rating that is suggested.