Good on Fuel?

I used cruise control at 50 through the long average speed section on the M1 and got 27mpg on the MID. It was trundling along just around 1500 rpm so I think that's about as good as mine will do. I have done lots of tests (and my MID is spookily accurate) but don't see much difference between 70, 80 and 90mph. If the run is completely clear i get about 24mpg, the first smell of traffic and it drops like a stone.

I found that I was able to get the best consumption if I was able to keep the revs steady at ~2000rpm, this meant manually shifting gears with the 4-speed auto and no hard accellerations, this way I managed to get my consumption down to 14l/100km, while I normally average 16-18l/100km

That said during a blast through Germany at speed from 140kph-250kph I avaraged 16l/100km.

I believe that its all the stars and stops that really makes the consumption bad while driving on smaller roads, and a steady highway cruise it's not that bad.

I can get it down to 10l/100km on the highway, average this far is 14.22l/100km

Best speed from my experience is 115kmh for long cruise for my m60. If there is no uphill 90kmh runs well. But if the speed is around 110-120, there is no need to apply more throttle to climb the hills. Last week I hit the 7.8lt/100km average during 95kms run