Originally Posted by
matrixmike28
Chris sorry for the late reply. I was not at that race but I have had in depth conversations about it with those who were. Pretty much all of the guys I talked to reduced their head shims slightly and ran 40% or left their shimming stock and ran 50%. Make sure you are running either 8.5 or 9 for insert. This should put you into the good power range without having to overlean the engine and reduce its life. The guys at that race were going lean on the needles trying to get pro power so to speak and thus flame outs were everywhere. Hope that helps.
Thanks Mike,
Just for clarification I race at these altitudes all the time, I have run RB, Novarossi, TecnoPower, and helped many of OS owners. I ran the nationals at that track with zero flame-outs all week, and had no problems making power. All the engines I have run and have direct experience with respond in different ways to different changes up here. My RB's respond best to an extra .10 head shim added and 50% nitro. Nova seemed to respond best to removing a thin shim and sticking with 30% and med plug. TecnoPower seemed to like stock shims with 40% and #6 plug the most. The VZB OS engines don't like having shims removed as much as they liked to have nitro increased in my experiences up here.
These are the kind of answers I was looking for that relate directly to a GO engine. I know what to do at altitude as this is where I race and my stuff runs just fine. I was hoping for a straight up answer because I would want to know what to suggest to people if I recommend they get a GO engine as an engine for next season. If GO's respond best to pulling headshims I would like to know because for a new person I would generally offer to do it for them or show them how.