Petrol Tips: What is good fuel economy?

If you’re thinking about buying a car, you’ve no doubt thought about fuel economy, as it’s going to have a big impact on the cost of the vehicle over time. Good fuel economy means your car is going to go further using less fuel, and save you money in the process. It’s also kinder to the environment.

But what if you already own a car and want to know how to minimise those expensive trips to the bowser? With petrol prices never certain, it’s a good time to think about using less fuel. Here’s a few handy tips so you can get the most out of your ride.

What is fuel economy?

Fuel economy relies on lots of different factors, but at its core it’s the distance you get out of a tank of petrol, measured in the amount of litres you use per 100 kilometres. The less litres used, the better the fuel economy.

Good fuel economy is generally considered as anything below about six litres per 100 kilometres, with bad fuel economy being anything over around 12 litres per 100 kilometres.

How to work out fuel economy

If you want to work out your car’s fuel economy it’s pretty simple.

When you next need petrol, fill up your tank completely. Reset your trip metre which is located on the dash, to zero before you drive away. Drive around as you would normally until your tank is at least half empty (the more petrol you’ve used, the more accurate the reading). Fill up the tank, noting down how many litres (L) you’ve put in. You’ll also need to write down the kilometres (K) on the trip metre.

Then, do this equation to find out the number:

L (Litres filled) divided by K (Kilometres driven) x100 = Litres per 100 kilometres

If you do this regularly, it’ll help you keep track of your average kilometres driven per year, giving you an even better snapshot of how much your car is costing you in fuel.

How many km per litre of fuel is good for your car?

This really depends on your particular vehicle’s make and model, as different cars will get varying amounts out of a tank of petrol. When you add diesel and LPG to the mix, it’s even more varied.

The main takeaway is that whatever car you’re driving, there are things you can do to make it as efficient as possible.

What causes poor fuel economy?

Fuel economy differs by vehicle type and the type of fuel used, but there are lots of other factors that can influence it too. How you drive, whether you’re towing loads, or if you’re taking it off-road can all have an impact on your car’s fuel economy.

Let’s take a look at a few things that might be giving you poorer fuel economy than you’d like.

How much does weight affect fuel economy?

Heavier vehicles take a lot more power from the engine to get going, so it stands to reason that weight is a factor when it comes to fuel economy.

The weight can come from the build of the vehicle, or aftermarket modifications such as winches, bullbars, and bigger tyres. Even carrying cargo in the boot, or storing a full-sized spare tyre will have an impact on how much fuel you use.

In fact, for every 100 kg weight reduction, your fuel consumption savings could be up to 0.4L/100 km for cars, and 0.5 L/100 km for light trucks. It might not seem like much, but it adds up over time*.

To use this to your advantage, buy the smallest car you can that suits your needs, and don’t carry around unnecessary items in your car that you aren’t using.

Better to store them somewhere they won’t cost you money!

What wastes fuel the most?

A lot of things influence your car’s efficiency, but how you accelerate is probably the number one reason for poor fuel economy in everyday driving.

Rather than accelerating quickly from stopping, ease up to speed. It also pays to stay at a steady speed if you can. Stay back from the cars in front of you to anticipate traffic and drive more consistently rather than stopping and starting.

Does driving faster waste more fuel?

How you drive definitely impacts how much fuel you get from a tank of petrol, so if you like to put your foot down, you’ll be filling up more regularly.

Your car is most efficient between 50 and 80 km per hour, so driving faster than this is going to cost you more. Obviously you can’t control the speed limit, and it’s dangerous to drive too slowly on the highway, but consider taking it easy in the left lane to save on petrol.

How to improve fuel economy

Aside from what we’ve already mentioned, there’s a few steps you can take to make sure your car’s getting the best fuel economy possible:

Learn more about your car

Now that you know how to save yourself money by maximising your fuel economy, why not read even more in our other mycar blogs? You can find out if you’re a good driver or have developed some bad habits along the way, or even learn about fuel pumps.

And if you have any questions about your car, pick up the phone and call one of our expert mechanics who’ll be happy to give you any advice you need!

Source: "A recent study found that for every 100-kg reduction, the combined city/highway fuel consumption could decrease by about 0.4 L/100 km for cars and about 0.5 L/100 km for light trucks (MIT 2008)."
https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/oee/pdf/transportation/fuel-efficient-technologies/autosmart_factsheet_16_e.pdf