[naturalextraction]

What kind of vehicle is this, the 93 Honda Del Sol? What type of A/F ratio meter are you using and where is the wide band 02 sensor placed. Is this after market metering devices? Most gasoline internal combustion engines of any sort including older lean burn engines will loose load pulling power at 18 to 19:1. Without a turbo or a better means of maximizing heat energy losses or the ability to utilize more internal energy of the fuel, I suspect that where or what you readings are may be off a bit. Also slower burning fuel such as a higher octane needs the higher compression to provide a more complete burn unless you have advanced your timing accordingly. Most cars that are not higher performance models run at 8:1 to 8:75 and will not gain any performance or mileage with a higher octane. Just some quick thoughts. Accuracy is where all will benefit from your gains. Keep up the good work.