Originally Posted by Chris Peralta

I have been racing at altitude for 5 years I know what happens with the power. This is why I am asking about GO's not engines in general.

Originally Posted by inferno13

the general formula for power loss with increases in altitude is 3% every 1000 ft above sea level if you race in colorado at 5000 ft instead of california at sea level you can expect to loose 15% power output out of your engine if the engine is tuned proper, running at higher altitude requires a leaner mixture setting than running at sea level, tune accordingly for good performance.