hehehe....
hmm top gear was repeating on one of the UKTV cable channels last night, it had clarkson in the A8 diesel V8 trying to do london-edinburgh and back on one tank - you're still doing better than he was at a steady 55mph + coasting + near-zero electrical load
he only got it over 40mpg once fear crept in that it was going to conk out, and then not far.
(the success of the challenge being more down to the enormous tank and the large safety margin audi built in to the fuel guage and trip computer, than any startling economy)
im consigning this tank in the azzy as an official "fuel crisis marathon challenge tank". so far done magic-carpet wafting round town and getting to/from notts at 55-60 - or less, where it wasnt going to force trucks to overtake me on a 2-lane motorway. led to me almost getting myself killed overtaking some nit doing 34mph up the country B-roads (had to change out of top, reckoned that a short stab in 3rd would actually save fuel overall) just as they accelerated and coming face to face with another person charging round a corner... ah the challenges of fuel saving!
can only hope to get close to your 50mpg, overall. from some protracted maths based on the official figures, i worked out that doing a steady 53 should see the beast get 60mpg... time will tell the truth of that. But i'm up to 175 miles with the petrol needle where i might ordinarily be content with 100, so not that shabby!
two interesting things coming of that - im wondering how biased the new-style economy tests might be towards diesel power, maybe skewing things. the manual lists both the old style 90/120k and city figures, plus the new urban/country/combined... looking at the two, the new style definately paints petrol cars as worse than the old one, and diesels as better. Not sure quite how that works, but i suspect trickery. Maybe too much reliance on the in-town figure, as the old ones quite nicely highlight how derv burners work best under load - they're drastically less thirsty round town, but at a constant part-throttle 55 or 75mph, there's only a credit card's width between the two fuels.
and also, for all people's yawking about how expensive petrol is, there's little sign of them easing off the throttle and saving fuel even when they should. the second leg of my eco-run was blessed by fairly bad rain, and the standard of both general driving and economy concern was terrible. Less than a single car length gap being left - in the wet! - at 60mph, adding up to less than the likely stopping distance for one car across a whole 10-car queue, nearly no space being left when charging up behind and then cutting into outside lane, lots of hanging on at the back of a queue seemingly in 4th gear charging up to speed and then braking hard again when it's average speed was plainly only 1 or 2mph more than that of the left lane and both of them could be taken at an easy constant speed cruise in top, using half the fuel...
general knackerage the same as mine... (to be honest my synchros seem a bit sluggish, too, though not grinding yet)