sudden increase in MPG

[Owd git]

I've lately been doing a regular journey from the Midlands down to Portsmouth in t'Déesse (THP) - M1, A43, M40, A34,M3, M27 - mostly dual carriageway.

Being on the thrifty side when travelling on business I've been keeping the speeds down to 65 - 75 to squeeze a bit more out of a gallon and I maxed out at about 47 mpg.

Not the same journey but similar enough I would have thought, I went down to Wallington (Surrey) yesterday via M1, M25, and then through Epsom and so on and managed over 52 mpg without really trying (didn't thrash it cos the OL was aboard).

How's that happened then? Well the car went in for some warranty work a couple of weeks ago and the only thing I can think of is I've had a firmware/software update.

Anyone else seen this? - oh I get most of me fuel from Sainsburys and for the purists all this is according to me trip 'computer' - can't be arsed to keep records

[jazd71]

Thats a good increase, could be a software update, you should try shell fuels see if that makes a difference to mpg, I travel in excess of 25-30k a year and have tried all makes of fuel and always go to shell, seems better quality of fuel and I always get better mpg from it, some supermarket petrol seems of s inferior quality a freind in the petrochemical industry also told me that supermarkets use inferior grade fuel (older) and put in additives to keep it fresher which I'm told "isn't a great thing for fuel". I know every one has their opinions on these are my findings and where I live shell is no more expensive than Sainsburys.
Have your tried V power in your machine?its more expensive but very clean burning, i use a tank full once a month in my HDI makes a difference in mine, mpg and responsiveness but cant afford to use it all the time.