What is more economical.

[DimmaThanDim]

Hi, I thought that i would add some food for thought to your debate. I used to use a 3.0 v6 citroen xm for towing my race car around the country. It was an auto which made towing long distances a much more pleasureable task. Problem with the car was that it only started to come on cam at around 2700 rpm. towing at 60 mph (legal max) at around 2200 rpm would return me around 18-20 mpg. When the towing speed was above 75 mph (as if I would) at 2700 rpm, the car would return 26-28 mpg with less throttle as it was running on the lower edge of the power band and therefore running more efficiently and thus giving less pollution. Just glad i never had to try and explain this to our ever so nice traffic friends.

[HDi fun]

2200rpm in a V6 petrol is way below peak efficiency, hence the poor return on fuel. The power band is also the most efficient in terms of fuel band.

My car is geared high - 3000rpm is 97mph in fifth (diesel, so revs are limited a bit). But there's no point in using 5th at 45 mph. Unless you really want to eat fuel, that is. There's no turbo pressure to speak of, so the ECU reverts to good ole' pile the diesel in option to keep it going at all. Hence, sod all miles per gallon if you drive awalking pace in high gears.