Originally Posted by Nixlimited

Are these calculations based on the on-board computer, or based on actual fuel-usage figures (e.g. fill up and record mileage and gas usage)? I can see a scenario where the on-board computer would miscalculate gas mileage on the high-end. For example, if the on-board ECU used injector pulse length to calculate fuel use, but you had larger injectors, then when cruising the injector pulse would be shorter because the injector is larger, but you are probably using the same or more gas. I just have a very hard time believing that a TT sports car is rivaling hybrid gas mileage on the freeway.