I think you got your “reply” mixed up with the “post new” link…
But in case you did mean to write to myself specifically, I will say to you that I think the Shell Girl-Power fuel does make for a bit more performance, and it is the only fuel I can get my best mpg figures with.
Your more modern engine might be less impacted…
I personally always drive as if the brakes have failed. Anticipation and distance from the car in front are what is needed to get the best “economy”.
I can drive from Haverthwaite to Cark without touching the brakes once, at an average of 55 mph, if there is no traffic.
Driving as if you have no brakes is a skill and ‘something to do’ for sure and gives me the best mpg I get too. But not IMHO really compatible with ‘spirited’ driving even on public roads.
I have done back to back, brim to brim computations on diesel and petrol (not in the same vehicle!!) and my conclusion is that there is no difference in MPG. External influences such as wind speed, direction and rain has a bigger influence than the type of fuel.
We have a D4 S90 Volvo which averages 10 MPG more than the Mazda. The diesel will do high 50s at motorway cruising speeds. Modern petrol engines are seriously economical but I believe that you will still have trouble beating a modern diesel.
I’m having fun driving around Spain and Portugal at the moment, and top up at the start of every “leg” of our journey as we have no idea when we may be able to fill up again.
I haven’t a clue what the mpg is… but sure having fun, outside of cities hardly any traffic, and when you get held up, wait for the infuriating double white lines to stop, and drop a gear (or two), and give it some
Roof down fun, not worrying about mpg. (I have a D2 Volvo at home for 50 to 70 mpg for commuting)
Get out there and enjoy your car!!
Took the snotter (330 D touring) to the NEC for the Restoration show in March. Driving carefully I got a remarkable 68mpg. On the return leg with much more traffic I got about 63mpg which gave an average of over 65mpg over 140 miles of mainly motorway driving.
Heavy braking and hard acceleration kills the economy.
Just found in our loft Dec 2010 STHT article written by my wife ‘The National Rally in 2010via John O’Groats’, we clocked 2039 miles and according to my fuel log returned 46 mpg, not bad for my long since gone NB 1.6.
Petrol won’t stand a chance against diesel in any situation re: economy in a like-for-like comparison.
For example, I used to have a 308 SW 1.2 petrol. Only every got 49mpg on a long run, and that was rare. ( no traffic at all) Changed to a 1.5 diesel 308 (same car type) and I get 68 mpg on a long run. And averages 52
350 miles last weekend on mainly uncluttered motorways and dual carriageways driving at more or less the speed limits gave 52.3 mpg brim to brim on my 2016 1.5 ND. I recently had ClearR Motorsport use VersaTune software to optimise the ECU for 99 RON fuel.
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