The cost of living is rising, so now more than ever saving ever dollar counts.

    That got us wondering about the best ways to save fuel. Driving less is one option, but it’s not an option for everyone – so we decided to put some popular theories about how to make every litre count to the test.

    Our tests were conducted at the VinFast proving ground in Lang Lang, Victoria, using a Toyota HiLux GR Sport ute powered by Ampol Amplify premium diesel.

    Read on to see how each stacked up, or check out the video below.

    Our control test was conducted with the car in its default drive mode, with tyres at placarded pressures, and the air-conditioning set to Auto and 23 degrees in the cabin.

    We drove the vehicle on the high-speed bowl at the VinFast Proving Ground for the sake of repeatability.

    Changing drive modes

    Most new cars have some sort of Eco Mode, along with a Normal Mode, and a Sport Mode.

    Although they don’t change the amount of power the engine makes, they do usually change the throttle mapping.

    In Eco Mode, you need to press the accelerator harder to elicit the same level of response as if you were in Sport Mode.

    Does that also have an impact on fuel consumption?

    60km/h100km/h
    Control (Normal Mode)4.9L/100km8.1L/100km
    Eco Mode 5.2L/100km8.4L/100km
    Power Mode5.2L/100km8.4L/100km

    Air-conditioning, heating, and windows

    What impact does using the air-con and heating have on fuel consumption, and how does it compare with rolling down your windows?

    60km/h100km/h
    Control 4.9L/100km8.1L/100km
    Driver’s window down5.3L/100km8.6L/100km
    All windows down4.9L/100km8.5L/100km
    Air-con on maximum cold5.5L/100km8.6L/100km
    Heater on maximum hot 5.2L/100km8.3L/100km

    Tyre pressures

    Tyre pressures are important in a few key ways.

    Under- or over-inflated tyres can impact the handling of your car, and incorrect pressures can accelerate wear.

    Getting your tyre pressures wrong can also cost you money at the fuel bowser, as our figures below show.

    60km/h100km/h
    Control (placard pressures)4.9L/100km8.1L/100km
    20PSI5.9L/100km8.9L/100km
    42PSI5.0L/100km8.8L/100km

    Adding weight

    Weight is the enemy of handling, performance, and fuel economy.

    Don’t believe us? Check out how much more fuel a HiLux with 500kg in the tray uses than the unladen car.

    60km/h100km/h
    Control 4.9L/100km8.1L/100km
    500kg load5.6L/100km8.6L/100km

    Scott Collie

    Scott Collie is an automotive journalist based in Melbourne, Australia. Scott studied journalism at RMIT University and, after a lifelong obsession with everything automotive, started covering the car industry shortly afterwards. He has a passion for travel, and is an avid Melbourne Demons supporter.

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