On Feb 18, 2:18*pm, "js.b1" wrote:
On Feb 18, 11:39*am, Nightjar
wrote:

On 18/02/2012 10:51, js.b1 wrote:
There is the german autobahn a short trip away. They have unrestricted
autobahn use - wrapped up in very restrictive and punitive fine areas..
High speed use will get 14-18mpg on many cars.

I was getting around 32mpg at a steady 160kph.

99mph, not that fast and whilst drag is higher it is not that much

higher than 75-80mph.
It is as you pass 140mph that drag takes over, bhp required rockets
and mpg begins to collapse.

The main form of drag varies as the square of speed. There is no magic
number at which it suddenly happens.
As you are an idiot, that means if you go twice as fast you get four
times the drag.
If you go three times as fast, you get nine times the drag.
http://en.wikipedia.org/wiki/Drag_equation