Well it all just gets more bizarre. I think my Bongo has just returned 37mpg.
We set off from Manchester for Thirsk, quite well loaded (two occupants and all the band gear) and we took it easy, using M60/M60/M1/A1(M) so probably 60-65 mph plus a long 50 mph speed restricted stretch around Leeds. The wind was from the North. The air was cold and fairly dry. I'd topped up before setting off, and I noticed that the fuel gauge (whose habits on long cruises I know pretty well by now, and the gauge is well earthed and functioning well) was going down slower than usual. As we were splitting fuel cost, we topped up in Thirsk, when the odometer had 100 miles on the clock, and we needed 12.2 litres. This worked out at fractionally over 37mpg. The best I've ever recorded before is 32 mpg (although I recall one occasion where i suspected it might have done nearer 34mpg, with 25% veg oil, a following wind, and speeds of 65-70 mph). I do have 215/55/17 tyres so they will probably help when cruising, but still, I am trying to work out what might be causing misleading figures. I guess end errors are an issue when only topping up with a small amount (did I squeeze as much in on the refill as on the original fill-up although I certainly tried to, and both petrol stations were on the flat, well perhaps the first one had the Bongo sloping slightly forward). Met conditions would I guess have encouraged good turbo performance. etc. etc. And there is the fuel gauge position to be considered (it had definitely dropped less than it has before over that mileage).
Interestingly (though I didn't fill up to check) the gauge suggests we didn't do so well coming back despite similar easy driving, but in warmer wetter air. It was still good though and I would guess it was about 32mpg.
Whatever the true figure was, it was bl**dy good. Which makes the (diesel) Bongo not a bad motor really for fuel consumption, provided you take it easy
