17 replies to this topic

[Ethel]

Drag increases at a cubed rate at any speed. The work you're doing is displacing the mass of the air infront of you, so at a constant speed the force you need is that mass of air times its acceleration to get fast enough to get out of your way. As your speed increases the air has to accelerate even faster, and because you cover more distance in the same time there's more of it to shift. F=MA has become F=MxMxAxA. Best economy will be found at the point where the external losses through drag start to exceed the internal losses of spinning the engine & transmission - mostly heat. It does follow that it will vary depending on conditions: battling a head wind will reduce the optimum speed, a tail wind increases it, and it's worth letting your speed increase downhill to carry you up the other side. Braking is the killer, don't try to do more speed than you can carry round the corners on the twisty stuff and leave plenty of room in stop go traffic.

[minitman]

Check out the big brain on Brad! (Pulp Fiction?)

More seriously, top answer Ethel. I'm not clever enough to appreciate the technicalities but good effort and sensible advice too.

TehMarchant,remember to save your energy for when you arrive, and plenty of fluids whilst on the journey down.

Long distance relationships are hard but can work very nicely. I know, I am from down south but now live in Cumbria. A lot of miles, flat out, previously in a 998 mini City. (Now 1380) Don't worry about the best speed the mini will find it's own limits.

[Cooperman]

Aerodynamic drag increases as a square of the speed through the air. That is a basic law of aerodynamics. On road vehicles this formula can change slightly due to 'ground effect' and some other minor factors. However, it is true that to double the speed will require about 4 times the power.

The Mini is particularly non-aerodynamic, so economy is never going to be good when the cruising speed is considered.