As the fuel levy and the price of crude oil increase, while the value of the rand decreases , we’re left with less disposable income each passing year. We do not need to get rid of our cars, however we can merely decrease the stress and save of fuel while we drive. 

The faster you go, the more fuel your car uses and a lot of this has to do with drag. With increased speed comes more drag. Even worse, drag goes up at the square of your speed. In other words, if you double your speed from 60 to 120 km/h, the drag you must overcome (by burning more fuel) will increase fourfold.

Running the refrigerant compressor sucks engine power, which in turn uses more fuel. Use it only when you  can’t bear the heat.

If you have a vacuum gauge fitted or own a car with an econometer (they’re largely the same thing), you would notice the difference in fuel consumption on ascents and descents. The inlet-manifold pressure drops when you accelerate and heads up to a partial vacuum when you ease the throttle closed, thus using less fuel. Employing cruise control is best to maintain a constant speed, which is good for consumption but, if you allow the car to lose some speed up the hills and regain this with free downhill momentum, you will save precious fuel.

Whenever you use your brakes, you’re converting fuel energy into heat and all you gain from the energy loss is coming to a halt. Anticipate having to slow down when approaching traffic lights and stop streets. Maintaining your speed and having to slam on the brakes not only wastes fuel, but wears out tyres, brake pads and discs/drums.

Always keep your focus on what is happening a few cars ahead. Is the traffic slowing? Is the next traffic light green? If so, chances are by the time you reach it, it will have changed to red. So don’t rush. If it is red, cruise slowly towards the lights in the hope that you can sail through as they turn green.

On the face of it, it would seem there’s nothing you can do about this. The larger the frontal area of your vehicle, the higher the drag and the more fuel you’ll use. It’s why an SUV uses more fuel than a small hatch. But did you know that, in Johannesburg, you have less drag than at sea level since the air is “thinner”? Car designers obviously try to blend attractive shapes with practical low-drag aerodynamics, but there are other ways you can compensate:

It may look cool to have a surfboard or kayak on the roof but these play havoc with your drag factor. Use them only when you are actually heading down to the water’s edge.

Don’t, however, do this if you often drive on gravel roads or if you drive a bakkie or truck because these are safety items preventing stones and bricks from being flung into the vehicle behind. Likewise, don’t remove your aerodynamically inefficient windscreen wipers (yes, some people actually do this).

For the many bakkie drivers out there, consider adding a canopy or load-bay cover. According to wind-tunnel tests, a cover can reduce drag by more than five percent. This could reduce your fuel consumption by one to two percent.  

As an experiment, we made use of our standard fuel route and chose a Toyota Hilux Dakar 2,8 GD-6 4x4 with a manual gearbox as the test mule. The manufacturer’s claimed fuel consumption is 9,1 L/100 km. Completing our fuel route while driving normally returned a figure of 8,3 L/100 km. Using power mode on the freeway, some sandbags in the back and driving a bit more aggressively with higher revs before changing gears, the figure climbed to
 11,1 L/100 km, or 22 percent higher. This gives us a good example of how much cash you can save by taking it easy and using common sense.

Diesel engines are getting hammered by European politicians, to the extent they are being phased out, but the fact remains they are generally still more economical than petrols. This is especially the case when having to sit in slow-moving traffic because a diesel tolerates a leaner mixture. In a decade or so, we could all be driving electric vehicles but only if battery technology continues to improve and their prices continue to shrink.

CarMag