55mpg isn't unusual. Over the various hdis I've had, from estates to 3drs, 100k to 270k, standard and mapped. Always end up between 50-55 mpg over a tankful.
You are right that keeping 70 with a heavier car will use a small amount more fuel...but tyen it also gives you more momentum to take through corners and at the bottom of hills... It won't make much difference real world. I didn't even get worse mpg tugging a trailer with a fully loaded estate lol.
You are right that keeping 70 with a heavier car will use a small amount more fuel...but tyen it also gives you more momentum to take through corners and at the bottom of hills... It won't make much difference real world. I didn't even get worse mpg tugging a trailer with a fully loaded estate lol.