Today’s media bug bear of choice seems to be the fuel consumption figures that car manufacturers provide. Many people claim that these figures are unachievable, as car manufacturers basically “cheat” to come up with them. The Guardian newspaper even posted an infographic here showing various ways this is done, from pumping up tyres, or using ones with specially low rolling resistance, to putting low friction oil in the engine.
A lot of these “cheats” aren’t terribly complicated though. So surely ordinary folk can save fuel by applying these methods to their own cars?
Certainly, looking at the infographic, there are a few things the average motorist can do. For example, some motor oil companies claim their flagship products save fuel, clean your engine and make starting on cold, winter mornings easier, as well as lubricate your engine. From personal experience, this blogger can attest that certain brands do actually make good on their promises.
Then there’s tyres. Inflating them to the correct pressure ensures your car will have the optimum balance of grip, tyre wear and safety. It is a well known fact that pumping them up more will make your tyres more fuel efficient, but at the expense of that optimum balance. It is far better to buy energy saving tyres instead, which are now produced by several tyre companies, and again from experience, these also make a worthwhile difference to a car’s fuel efficiency.
Choosing an efficient tyre has also been made easier as of late, due to the new EU tyre labelling directive that has come into force, (see our previous post New EU Tyre Labels). The new labels feature a fuel efficiency rating, so it’s very easy to spot a tyre that will genuinely save you fuel.
The infographic also mentions gears. Most of us are well aware of how to use a gearbox properly, but what is not so commonly known is that the standard test for fuel efficiency figures uses quite low revs, hovering around 2,000 rpm for a lot of the time.
So, why is this important? In many motoring magazines you will often find car manufacturers boasting that their engine produces 80% of it’s torque – “from just 2,000 rpm!” Basically, this is a byproduct of them engineering their cars to be as efficient as possible around 2,000 rpm, because then they will then perform well in the fuel efficiency test. It follows that keeping a car’s engine running at around this figure will enable a driver to also potentially achieve similar fuel economy to the test fuel consumption. In fact, it’s quite remarkable how many turbo cars seem to come on song just before this point in the rev range, whether petrol or diesel.
Lastly, nearly all modern cars now have a trip computer that displays fuel usage, (like the picture above). This can be particularly useful for a driver to work out the best gear to use for any given situation, or to monitor how efficient their own driving is, because at the end of the day, your driving style is still the single biggest factor that determines how much fuel your car uses.
Happy (and frugal) Motoring!