10 tips to save fuel

Of all the expenses incurred in running a car, expenditure at the fuel bowser and financing costs, rank second only to depreciation.

Like death and taxes, depreciation and financing can’t be avoided, however anything which can reduce fuel consumption is, to most of us, welcome advice.

Unlike depreciation, there are ways to mitigate fuel costs, and deliver a pleasing cut in annual expenditure.

Following is a list of 10 relatively easy steps which can help incrementally in achieving this goal.

Which car?

Whether you’re buying a large, expensive luxury car or a super-economical small car, the fuel consumption potential should be a consideration. After all, using less means you’ll be travelling greater distances between those time-wasting stops to fill-up.

To glean how your prospective new car rates for fuel use, simply read the ADR fuel economy placard which must be displayed on new vehicle windscreens. The figures quoted are achieved through laboratory testing - they don’t necessarily reflect real-world use – but do give some clue on the relativity between ‘your’ car and its rivals.

A diesel-engined car will show lower fuel consumption than a comparable petrol model, but do consider the pump-price factor as diesel is invariably priced higher than regular unleaded petrol.

The choice of petrol or diesel depends on planned usage. If you are buying a car to only carry light passenger loads, the fuel consumption rewards for a diesel will be less than if you’re planning on buying a heavy off-roader with intentions to tow a weighty trailer, horse float, caravan or boat.

The route you take to your destination plays a huge role part in fuel consumption.

Taking the freeway will obviously result in a more fuel efficient drive than using secondary roads and suburban streets. Likewise a road which is straight and flat will see fewer prods at the accelerator pedal than a road with hills and curves.

Sure, not everyone enjoys convenient access to a freeway, but some lateral thinking – or the use of your satellite navigation – could help trim the fuel bill.

It might sound obvious, but injudicious use of the accelerator pedal is one of the most sure-fire ways of using more fuel. Head-jerking take-offs, or unnecessarily stomping the pedal to the floor while driving, are bound to feed more fuel into your car’s injectors than more measured applications.

Without mentioning the higher levels of CO2 which will be emitted by the exhaust pipe, that driving style will also probably impart extra wear – and thus costs – in areas including tyres, brakes and transmission.

A manual-transmission car is best driven in a conservative range which keeps engine revs within the most fuel-efficient zone. Many cars today have a shift indicator advising when it’s best to upshift or downshift to avoid over or under-revving – either of which can impact fuel consumption.

Driving smoothly means more than just treading lightly on the gas pedal, or avoiding tyre-squealing bravado when cornering.

Driving smoothly also mandates the driver anticipating what’s coming up.

Being aware of what is unfolding in the traffic ahead assists road safety and provides time for you to gradually match speed with the vehicle ahead. You’ve no doubt seen the opposite: Drivers who constantly race-up swiftly behind the car in front, brake forcefully and then need to re-accelerate in order to regain their previous speed.

The same applies when you’re enjoying a bit of a blast on a quiet, winding road: The best and most satisfying technique is to be smooth, not just with steering and accelerator, but also by braking progressively rather than viciously.

You’ll save fuel, and you’ll save brake maintenance costs as well.

A turn-off can be a good thing

Many new cars improve their economy rating via idle-stop systems which automatically shut down the engine when you’re sitting immobile in traffic and likewise re-start immediately the driver releases the brake pedal or applies the accelerator.

These systems require a more robust starter motor, so if your car lacks this technology we don’t recommend manually turning your engine off in traffic. But if you’re sitting waiting for a gigantic freight train to pass, to collect the children from school, or in gridlock traffic not going anywhere soon, switching the engine off is a great way to save fuel.

If you want to take things a step further, we also recommend shifting to neutral when stopped with the engine running. Resting the car on the torque converter (automatic transmission), or riding the clutch (manual transmission), burns fuel and wears parts. So, slip out of gear and save.

And when off-road, allowing your turbo-diesel 4WD to tick over for half an hour while milling around deliberating which track to take is not only annoying noise pollution and fuel-wasteful, it also pumps out unnecessary pollutants into the atmosphere.

It stands to reason: The higher the parasitic drag on your engine, the more fuel it will use. But how does that translate to electrical ancillaries? And what about the air-conditioning?

The truth is, in newer cars, many of the auxiliary systems draw power from the engine on demand. In other words, if you’re using it, it’s on. And if you’re not, it’s off. The declutching of your air-conditioning compressor or power steering is a great example.

If it’s a mild day, or the climate control says the cabin is dry enough not to need it, the air-conditioning pump simply won’t engage. Ditto the power steering, which, in the case of some new electrically-assisted designs, shuts down when driving in a straight line.

Of course driving with every mod con switched on at once will sap power from the system, and in turn use more fuel. So, switch off or turn down the auxiliaries you can do without – except for the air-conditioning.

Because we can’t forget our old friend aerodynamic drag. Using the air-conditioning sensibly (running constantly at a modest temperature) uses less fuel than driving with the sunroof open, or windows down.

The best idea is, when first unlocking your car, open the roof and windows to allow hot air to escape, then close them as you move off to allow the air-con to work its wonders. Or better still, park under cover.

It’s impossible to overstate the role of tyres in optimised fuel use. These days many tyre manufacturers offer tyres made using compounds specifically designed for fuel economy. Called low rolling resistance tyres, their rubbers typically have a higher silica content than regular tyres and the decreased friction with the road means it requires less engine output to maintain speed when cruising.

Regular checking to ensure your tyre pressures are at manufacturer-recommended levels is as significant for fuel economy as it is for safety.

It’s also worth noting that alloy wheels usually weigh less than conventional steel rims (reducing your vehicle’s unsprung mass). But a gleaming set of alloys is usually accompanied by wider tyres which mean greater air resistance.

No one wants to sit in heavy traffic or drive in adverse conditions – and neither does your engine.

Avoiding stop-start traffic is a great way to save fuel, and will also reduce wear and tear – on both your car and you.

Put simply, the best time to save fuel is when the roads are empty and the weather is fine. So get up early and beat the peak-hour crush, or sleep in and wait until it has passed.

Bad weather impacts fuel consumption too. Wet weather increases the rolling resistance between your tyres and the road and means you’ll likely be using more of those auxiliary items (lights, wipers, air-conditioning) we spoke of earlier.

Likewise, windy weather can increase the aerodynamic drag on your car, and hot weather means more strain on your tyres, engine and air-conditioning.

You’re a family with youngsters requiring transport to school, the gym, soccer practice, netball training, swim meets…it’s a never-ending cycle in and out of the family car.

It’s no surprise fuel consumption seems to be off the scale.

Put simply, short trips are astonishingly less fuel efficient than long-distance cruises.

Some planning can make a major difference.

Consider pooling car use with other families sharing the same duties, or combine two functions into one round trip. With some considered thinking and team work, it’s possible to reduce the kilometres travelled, and thus fuel used.

Or think about walking with your kids to some venues – it teaches them to be independent and provides exercise for multiple family members.

High octane, or low octane?

Most fuel stations give petrol-engined cars a choice of three Research Octane Number (RON) ratings: The standard, and lowest rating applying to the majority of cars is 91 RON, while higher-performance cars require either 95 RON or 98 RON unleaded fuel.

The RON rating refers to a fuel’s ability to resist pre-ignition or “knocking”, a phenomenon heard as a rattling from the engine under acceleration, created by explosive, or uncontrolled combustion.

Without doubt, knocking is bad for your engine.

With high-power engines, it is necessary to use a higher RON fuel to prevent the knocking which may occur as a result of its increased energy levels (while delivering the best fuel economy).

Question is: Does the use of higher octane fuel increase engine output, and reduce fuel consumption in a less highly-developed engine with a recommended 91 RON rating? Not usually.

The best advice, for those wanting to get the best out of their car, is to follow the manufacturer’s recommendation. While the use of a lower-than-recommended RON rating could be hazardous in a powerful, highly-developed engine.

Filling up with 98 RON unleaded in your average runabout is usually a waste of money because the hoped-for benefits are unlikely to materialise. However, cars recommended to run on 95 RON fuel, or higher, may benefit from use of 98 RON.