I don't quite understand the need for economy/performance mode, are they not the same tuning? Both economy and performance tuning should be more timing, and mixture as lean as it can go without getting EGT's too high, or seeing knock.

The performance adjustments shouold be at a higher load and TPS, and the economy should be at a lower point on the map.

That way, if you want economy, just don't gas it hard, and max performance is always available by stomping on it.

I could understand if the different maps were for using different grades of gas, but otherwise I don't get it. Am I missing something basic here in tuning theory?

John C.