OP here,
I have since got rid of my i40 because the fuel efficiency was breaking me. Maybe it was my car, but whatever way i measured it i couldnt get anything close to the efficiency of the A4 i had before the i40, or the passat i have now. Mistake going near Hyundai.
Honest John users report 77-95% of the rated mpg figures depending on body style and engine, so it would seem your particular car, the fuel you use, or your driving style are the likely issue here.
I have a 2011 2.0 Passat at the moment and have squeezed 71.6 mpg on a run to the West without a/c, I admit I drove carefully but this efficiency cannot be matched by any of my previous diesels, 60 mpg is easily achievable at motorway speeds, in contrast my brother in law has an i40 and moans about his mpg so maybe something other than driving style is at play.
I have a 2011 2.0 Passat at the moment and have squeezed 71.6 mpg on a run to the West without a/c, I admit I drove carefully but this efficiency cannot be matched by any of my previous diesels..
Impressive, are you calculating that yourself on mileage/fuel used or is it a trip computer estimation? If the latter, they've been shown to read on the optimistic side, up to 20% in some cases!
The trip computer and awareness of mileage covered, I must do it more scientifically but to be honest it needs so little diesel that it is noticed in my pocket and I have driven diesel for years but it still is noticed.
I'm not mad about the car itself, it is functional, I don't love it so to speak but it is really easy and cheap to live with so I'm hanging on to it..