89 octane vs. 104 or 110 octane

[PKRWUD]

Al-
Octane equals burn rate. The lower the octane, the faster the burn rate. For performance, you want the quickest burn rate you can use without detonation. In otherwords, the lowest octane you can use without detonation is the best to use. Using a fuel with a higher octane rating than you need will actually slow the vehicle down. Mods that cause detonation, therefore, require higher octane. Advanced timing and increased compression are the two most common mods that create detonation. While advancing the timing will help a little bit with performance, increasing the compression will help alot. If you have 110 octane fuel at your disposal, 13:1 compression is easily attainable, and 14:1 isn't out of reach. Compression this high will greatly increase performance, but will hinder drivability. Also, keep in mind that once you install high compression pistons, you ALWAYS have to run high octane fuel.

Take care,
-Chris