The only place Real mpg is available to the public is at www.honestjohn.co.uk/realmpg/, but it is a completely automated system with some complex algorithms to prevent it being skewed by figures outside the parameters. You will get better economy from a small low power and low torque engine like this running it on Shell V-Power because that is what all current engines are optimised on and the torque enhancement has a greater effect on a low torque engine enabling shorter shifting and less time in low gears.