Help! I want this engine to run good.
I live up in Winterpark and yes the farther you go up in altitude the less air to burn (do to the lower density of the air). When I ran my car up here for the first time it did ok on 20%, in Denver it ran much better w/20%. Then I changed to 30% and then it ran much better up here at 8000ft elevation. Also at higher ele. the weather plays a part in tuning, on cool, cloudy days the air is a little "thicker" than on hot, sunny days. So on cooler days you can lean it out a bit (not much though, I would say an hour or two on your high speed needle).