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How Do I Know That a Car Is Fuel-Efficient or Not?

Educational  ·  December 9, 2021

How Do I Know That a Car Is Fuel-Efficient or Not?

There’s never a shortage of fuel-efficient cars in the market today. Unfortunately, some car marketers are guilty of over-hyping the efficiency of the vehicles they're selling. So, how can you tell if a car is fuel-efficient or not?

To identify a fuel-efficient car, you need to check its specs. A fuel-efficient vehicle will have a smaller engine, a lightweight body, better aerodynamics, and a smaller axle ratio. When buying used cars, bear in mind that properly maintained cars maximise fuel efficiency.

As you continue to read this guide, you’ll discover why fuel efficiency matters, how to find fuel-efficient cars, and what’s considered a fuel-efficient car by today’s standards.

Let’s get started.

Why Is Fuel Efficiency Important?

A fuel-efficient car will use less fuel than an inefficient car traveling the same distance. So, the importance of fuel efficiency boils down to two factors: emissions and dollars.

Less Emissions

Fuel efficiency is vital to anyone who cares about the environment and the planet. As mentioned above, a fuel-efficient car will burn less fuel to travel a certain distance. Burning less fuel also means generating less emissions in the air.

Summing up, a fuel-efficient car has a much smaller carbon footprint.

Fewer Dollars Spent on Fuel

Even if you don’t care too much about the environment, you surely care about your wallet. Again, a fuel-efficient car burns less fuel. Simply put, that means fewer trips to the petrol station and less money spent on fuel.

Not only will a fuel-efficient car save you money in the long run, but it’ll also soften the blow whenever fuel prices spike up as they do from time to time.

What Factors Affect Fuel Efficiency?

These days, car marketers are quick to label their vehicles as ‘fuel-efficient’. But what does that mean?

Well, to help you separate fact from marketing hype, here are the car specs that have a direct impact on a new vehicle’s fuel efficiency:

Engine Type

Naturally, the first factor that determines a car’s fuel efficiency is the engine type. For starters, diesel engines are more efficient than petrol ones because you get much more power output per tank of fuel.

Of course, if you’re looking for an everyday family vehicle, petrol engines might be the only choice you have. Still, the type of petrol engine also affects fuel consumption.

For instance, an engine with four cylinders will burn fuel more efficiently than a gas-guzzling V6 or V8 engine.

So, if you’re shopping for a fuel-efficient car, start by comparing engine specs.

Weight

Another significant factor in fuel efficiency is the vehicle’s weight. Simply put, the lighter a vehicle is, the less energy (and therefore fuel) is required to move it.

With that in mind, sedans and compact cars will offer better fuel efficiency than vans and utes.

Aerodynamics

When a car moves forward, the air that passes it will generate some resistance (force in the opposite direction). The most fuel-efficient vehicles have aerodynamic designs, allowing air to move past the vehicle as smoothly as possible.

Now, you won’t see ‘aerodynamics’ listed on a list of car specs. Instead, you’ll have to judge for yourself by looking at the car. Larger vehicles will have poorer aerodynamics, as there’s a bigger surface for the air to pass over. 

On the other hand, smaller cars are naturally more aerodynamic, increasing their overall fuel efficiency.

Axle Ratio

Last but not least, we have the axle ratio. This factor has the most significant impact on the car’s fuel efficiency. 

The axle ratio refers to how many times the driveshaft needs to turn to rotate the axle once. So, the smaller the number, the more fuel-efficient the vehicle.

Unfortunately, you can’t choose different axle ratios for your preferred car model. Instead, the axle ratio numbers will differ from model to model.

Suppose you’re shopping for a more fuel-efficient car, make sure to look for the car model with an axle ratio of 3:1 or lower.

Overall Maintenance (for Used Cars)

When shopping for a used car, there’s one more factor that you’ll want to consider: the vehicle’s overall maintenance history.

You see, when you buy a brand-new car, all the car’s parts and components are new. Since they’ve experienced no wear yet, you can expect them to perform at maximum efficiency.

On the other hand, used cars will be somewhat out of tune with parts that are worn out. Lack of maintenance can reduce a car’s overall fuel efficiency by a few percentage points.

However, a used car that’s been kept in tip-top shape will be as fuel-efficient as it should be. So, aside from the car specs mentioned above, ask to see a maintenance history if you’re buying a used car.

Fuel-Efficient Car Trade-offs

The most fuel-efficient cars on the market today combine the best of all specs above with models that use fuel as efficiently as possible. However, there will be some trade-offs as can be expected. As a result, the car that caught your eye might not be the most fuel-efficient one there is.

In a word, you’ll have to recognize your priorities. If fuel inefficiency is the dealbreaker for you, then be prepared to choose a car that might not be the most visually attractive one at the showroom.

What Is Considered Fuel Efficient?

In this part of the world, fuel efficiency is measured by the number of kilometres you can get out of a tank of fuel. You’ll see that measurement expressed as kilometres per litre (km/L) or litres per 100 kilometres (L/100km). 

Therefore, the most fuel-efficient cars in Australia are the ones that give you the highest number of kilometres for the lowest number of litres of fuel.

To give you a sense of what to look for, consider these as general rules of thumb:

L/100km: A car that uses 6 litres or less per 100 kilometres is very fuel-efficient.

km/L: A car that returns 16.5 kilometres or more for every litre of fuel is very fuel-efficient.


To learn more about the most fuel-efficient cars on the market, check out the Blog at CarPart AU. There, you’ll discover plenty of updates on the latest goings-on in the automotive market in Australia and beyond.


By Ray Hasbollah

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