19-12-2021, 10:05 AM
Ethanol has only about half the calorific value of petrol so mpg will be worse. The 10% ethanol is like being sold a gallon 5% short. I am surprised about claims of different mpg with different octane ratings on basic petrol with pre computer cas. Spark adjustment would probably have corrected.
(Cars used to be set up not to ping at worst conditions. This determined the cr and hence efficiency. Cars now have crs which with conventional timing would ping wildly at full throttle. Instead the timing is computer retarded at wide throttle to avoid. The max power is much the same but the part throttle efficency is greatly improved by the very high cr.)
(Cars used to be set up not to ping at worst conditions. This determined the cr and hence efficiency. Cars now have crs which with conventional timing would ping wildly at full throttle. Instead the timing is computer retarded at wide throttle to avoid. The max power is much the same but the part throttle efficency is greatly improved by the very high cr.)