Stav, my current car achieves over 55mpg on the motorway (around 60mpg if there’s large stretches of 50mph temporary speed limits) yet only 35mpg on our usual short trips when driven economically (20-25mpg difference)
40mpg on motorway is even worse than I first feared. It makes me even more strongly believe that high 20’s seem to be what I’ll be achieving. Like I said, this is short, hilly, stop-start journeys.
Currently the cheapest (within 5 miles) unleaded is £165.9 and Super is £1.75.9. That’s only a 6% at the moment. I have used Super before (ready for MOT emissions test) and not noticed a difference, but this was a very basic comparison noticing how many miles driven before I needed to refuel. It’s certainly something I’ll try again and make note of types of journeys and get exact figures. I thought most written articles showed that the extra mpg didn’t pay for the extra fuel cost, but I’ll try again as it’s probably kinder to the engine as well.
One thing I am certain of is that your 27% increase in mpg using Super, is not the normal increase.