09 February 2022
GASO-LEAN: 5 ways to improve fuel economy for free

Practise these five tips to improve your fuel economy and you’ll be thankful for your tankful.

Fuel prices are on a sickeningly upward trend. At the time of this article, RON95 petrol costs at least $2.71 per litre after discount, while RON98 is selling for an eye-watering $3.19 for a litre of the flammable stuff! While it may be tempting to contemplate switching to a hybrid or even Electric Vehicle (EV), the current state of COE is likely to put many existing car owners off such thoughts to begin with. So here are five ways that you can improve the fuel economy of your car without forking out an additional dime.

1. Boot the junk in the trunk

As motoring journalists, we’ve lost count of how many cars we’ve seen carting around excessive ‘shtuff’ which didn’t need to be there. This author vividly recalls a scene years ago when one of his friends, who was driving her family’s Nissan Sunny, opened the boot to look for a set of jumper cables, only to be met by overflowing junk that was just shoved tightly in there.

Every additional kilogramme in the car causes more fuel to be burned. Leave the unnecessary bits and bobs at home and watch as fuel economy improves. However, if your car has a spare tyre, we recommend leaving it in the car since a flat tyre without replacement can quickly ruin one’s day.

2. Tank half-filled

In the same way that excess ‘shtuff’ causes excess petrol to be expended. More fuel in the tank weighs a car down more, which also leads to higher fuel consumption. The temptation to brim the tank at every fuel stop is great — this author knows it all too well. However, filling the petrol tank halfway means less weight to drag around. While requiring more fuel stops, this simple trick would undoubtedly improve fuel economy.

However, do not let the fuel level in the tank run too low. Topping up immediately once the low-fuel light on the gauge comes on is fine in most cases, but not too long thereafter and preferably before. This is because fuel pumps use petrol to keep themselves cool, and running the tank too low can lead to a hotter pump that may fail earlier in the long run.

3. Properly inflated tyres

Under-inflated tyres cause more drag with the road and rob precious fuel from the petrol tank because the engine needs to work harder to accelerate and maintain speed. The simple act-turned-habit of weekly tyre pressure checks and inflation to the car manufacturer’s recommended specifications has a pretty significant impact on fuel economy. Try to check and adjust tyre pressures when the tyres are ‘cold’, meaning within 2km of a cold start first thing in the morning. This is also where a portable rechargeable tyre inflator can come in handy to check and adjust cold pressures after a car’s been parked overnight before setting off.

While properly inflated tyres positively impact fuel economy, the urge to follow hyper-milers to over-inflate tyres must be avoided. Not only does the risk of tyre blowout increase, but this can also lead to reduced steering control, as well as additional uneven wear on the centre of the tyres, requiring more frequent tyre changes — not a financially prudent move.

4. Improve aerodynamics

We’re not referring to bodykits here. Aircon turned off with windows down at lower street-speeds to improve fuel economy is fine, but wind the windows up fully and turn on the aircon when out on the highway. Leaving windows down at highway speeds induces turbulence, which then causes more drag on the vehicle. Presenting a more streamlined shape to the air at speed with windows up drastically reduces this effect.

Same goes for other adornments such as roof racks and boot-mounted wings. While daily-driving and especially at highway speeds, these can induce more turbulence and therefore reduce fuel economy. Remove them where possible, unless and until they’re needed such as for a weekend’s wilderness-getaway or track-day respectively, and then and only then have them re-installed.

5. Drive more smoothly

The best way to improve fuel economy is to drive more smoothly. We don’t mean plodding along and holding up traffic — in fact, extended driving at speeds below 50km/h uses more fuel. Rather, gradually accelerate to match traffic speeds on the street, and keep to the speed limit on highways. Avoid sharp acceleration and sudden, jerky bouts of braking.

While on the move, anticipate traffic ahead. The less the brakes are used, the better for fuel economy. In the same way gradual acceleration saves fuel, gradual deceleration also does the same when acceleration will likely be needed again such as on the highway following traffic.

Use the expressways as much as possible. Start-stop traffic on the streets inevitably causes more fuel to be consumed due to frequent rounds of acceleration and deceleration, as opposed to the expressway where cruising speeds can be maintained for longer. While cruising at a steady state and right around speed limits, the engine uses minimal fuel to keep the vehicle moving along, as compared to acceleration where more fuel is sprayed into the engine to achieve increase in speed.

Even better is coasting in gear. This causes the fuel injectors to turn off completely and you won’t be using a drop of petrol. Some drivers might be tempted to slip their automatic gearboxes into N (Neutral) and coast even further. That’s actually a more advanced technique that only works if you know what you’re doing and it’s frankly too long and potentially contentious to explain here. For the most part, avoid doing this and just leave the gear selector in D while you’re coasting.

Try these five tips and you may be surprised how much further you can actually go on the same tankful of petrol.

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