[eschaider]

With or without a labcoat, altitude changes will require a retune on a speed density system. Significant atmospheric changes (altitude density) without a physical change in actual altitude, attributable for example to a weather front coming in or going out, will also require a retune. There is no way around the retune, it is inherent in the basiic design of the speed density fueling model. There is of course always the alternative where you simply ignore the need for a retune and it will respond similarly to a carbureted engine you choose not to retune.