Takes more than one tank of higher octane before the ECU will relearn HOW2 manage
Even longer if driven gingerly TRYING to get higher MPG
You must demand power mode often and for long periods of time
So the ECU will relearn to generate a new fuel mapping table(s) for Power Mode, which will also affect MPG
Maybe the OEM has limited the level of Power Mode allowed. So even aviation fuel won't mske a difference and if so, a tune will be needed
Plus there are other attributes in play. Main two are thermal limits and the auto trannys computer algorithms
