How To Reduce Your Cars Fuel Consumption

During a time where fuel prices are rising exponentially and climate change is the focus of automotive discussions, many consumers are looking to reduce their fuel consumption. They might switch their car for a more fuel efficient one, or even switch to an EV.

As the cleanliness of EV’s is still disputed, I’m going to concentrate on helping you reduce the fuel consumption of the car you already have. A lot of these points will also apply to EV’s, to increase the range, but ultimately that is not the main focus.

I’m sure you will have noticed the cost of fuel in some places is eye-wateringly steep. We can mitigate the tears by changing how we drive to consume less. Although the design of the vehicle can often be a limitation, there are ways to get the most amount of miles from each tank.

Whether they are worth it for marginal savings, that’s open to discussion. Regardless of your opinion, I’m going to provide some suggestions to potentially help you reduce the frequency of your fuel station visits.

More throttle equals more fuel. Consider whether you need to accelerate as hard as you do. 70-100% throttle in many vehicles is usually unnecessary during regular driving on the street.

How you drive is often dependent on where you are driving. Downtown in stop/start traffic will vastly use more fuel when regularly accelerating than braking. It’s getting up to speed, the initial movement that uses the most fuel. If you are on the highway, you are already up to speed and generally don’t need to accelerate hard.

You can’t always predict what is ahead, but use what you can see in front of you to your advantage. If you see a big hill coming up, accelerate before the hill rather than on it where possible.

Don’t brake or accelerate unnecessarily. Don’t accelerate hard then brake hard between lights. If you see the light ahead is red, cruise up to it gently. Gaining momentum from a standstill is one of the biggest fuel consumption killers.

Carry your speed on corners. Take this with a pinch of salt. I’m not suggesting you don’t brake or fly around at excessive speed, rather just maintain a comfortable level of grip while being safe and not braking excessively only to speed back up.

Select a gear where your RPM is at its lowest for the speed you want to travel.
There is a sweet spot, however. If your RPM is too low, the engine will struggle and may consume more fuel when you apply more throttle to compensate. Although each vehicle will vary, I would suggest something in the region of 1200RPM to 1500RPM at cruising speeds when less throttle input is required.
Even with many modern automatic gearboxes, you can sometimes have control over your gearing. Changing gear with an automatic transmission defeats the purpose of it being automatic. Although, if you find gear changes are happening higher up in the RPM, you could shift earlier and reduce fuel consumption. But this tip would be put to better use when driving cars that have three pedals.

When your tyre pressures are low, the tyre’s surface area increases when it sags. When more of the tyre surface makes contact with the road, the rolling resistance increases.

If you aren’t sure what rolling resistance is, think of it as a similar idea to drag with aerodynamics; driving with a parachute behind you, but on a smaller scale. It will slow you down and make it harder for the car to move forward.
Below is a graph from the Office of Energy Efficiency & Renewable Energy, showing the difference in fuel economy for different tyre pressures.

Use your gears to slow you down hills rather than solely relying on your foot brakes. If you don’t drive a manual car, don’t worry, most modern automatics often do this for you when you aren’t using the throttle.

The engine does not consume fuel during engine braking with most fuel-injected engines (unless you’ve asked your tuner to enable “pops and bangs” on your remapped Golf R).

Please note, engine braking does not replace your actual brakes, it’s just a method used to maintain a pace down a hill and to save on fuel. It will save you a bit of wear on your brake pads too!

Your speed and gearing will dictate your fuel consumption. Vehicles with fewer gears or shorter gear ratios may be limited in reaching that sweet spot mentioned in the previous point. If you want to sit at the speed limit that is.
For example, if you are in something like a Volkswagen Polo with only 5 gears; a car primarily designed for slower speeds. If you want to travel at 70mph, you might sit at 2500 RPM. Not a sweet spot for fuel economy.

One option is to sacrifice speed to gain in fuel economy. Slow down until you are at a safe speed but cruising at a lower RPM.

I can’t believe I’m writing this.

There is a limit though, on roads with fast-moving traffic, it’s often not safe to sit substantially below the speed limit. Use your best judgment for the road you are driving on.

Where possible, select Eco mode or the next best thing. Standard driving modes may be better than “Comfort” and “Sport” if you have an Eco option.
Eco modes often change the characteristics of the engine to improve fuel economy. Throttle response will be reduced, automatic gearboxes will change gear earlier.

Anything that consumes a significant amount of energy uses more fuel. Whether this is electrical or directly from the rotation of the engine. This is due to the extra load on the engine. It’s the power of the engine that turns the pulley on the alternator to recharge the battery and the AC compressor to keep you cool.

More fuel is used than usual to overcome the mechanical inertia from the additional load of the alternator and AC compressor; the effort required to function correctly.
Air Conditioning and heated seats are the biggest culprits for this.

If you haven’t seen the video from Engineering Explained showing when AC is more efficient than having your windows down, you should check it out.

Even I have thought myself that start/stop is pointless, a gimmick. But it can be effective. You just need to know a bit more about when it will and won’t save fuel. I would suggest any time you are going to be stopped for around 10 seconds or more, you’re likely to be saving fuel from your engine not running.

“But Simon, surely it’s more beneficial for the engine to not be running at all, at any time?”

Not always. When your engine first turns over to start, the quantity of fuel is substantially more than when the engine is idling. This is because the engine needs a big combustion kick (explosion) to effectively get up to speed and run smoothly as fast as possible, especially when using start/stop and you want to set off after being stopped at a red light.

Again, each engine is different, but in most cases, it is effective if you arrive at a red light or are sitting in heavy idling traffic. If you think you’ll encounter faster-moving traffic or are approaching a set of lights that have been red since they came into sight, you will usually have a button to disable start/stop. I sometimes just flick my gear shifter down into sport (S) when coming to a stop and it disables the function until I set off and put it back into D.

Keep in mind, that if you have air conditioning on, heated or cooled seats and devices plugged in, energy consumption or a temperature target for your climate control will usually disable start/stop automatically. This is when the electricity available drops below a particular threshold.

This is an easy one but often overlooked. Don’t leave your spare wheel at home, but I would recommend getting rid of junk. Golf clubs, non-emergency tools and household items you’ve been putting off taking to the dump. Out with it.

It can be mentally straining, always driving cautiously. Making small changes to save what might save a teeny-tiny bit of fuel. But if you change your driving habits, you might gain more than expected. Just don’t let them distract you from driving safely on the road or unnecessarily hold people up. Keep it sensible. I would promote comfortable driving over being too conscious about fuel consumption.

Sometimes you might want to adopt some of these methods when you’re low on fuel and are searching for a gas station. I’m personally aware of too many people who reach the pump with single-digit miles remaining. Don’t be one of those people. Fill up when the light comes on.

Not everyone reading this will give a flying monkey about saving fuel, start your engine and go. But if your V8 is costing you too much in fuel, you might consider a more fuel-efficient daily. It’s often not cost-effective to purchase another vehicle in my opinion, but do the sums, it might work out for you.

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