The biggest single factor that determines your fuel consumption is the type of car you drive. It stands to reason that a Smart car will burn significantly less than a muscle car. Research shows that cars with automatic transmissions use an average of 10% to 15% more fuel than manuals. Four-wheel drives guzzle more fuel than two-wheel drives.
But short of ditching your car for a new one, how can you reduce your fuel consumption? Here’s some handy tips on how to use less fuel, regardless of the car you drive.
Measuring your fuel consumption is a great way to keep on top of how effectively you’re saving fuel. If you have an on-board computer that measures fuel efficiency, then you’re in luck. This will typically show your average fuel consumption in miles per gallon (mpg).
If you don’t have an on-board computer, don’t worry. A few back-of-the-envelope calculations will do.
For example, if you’ve travelled 180 miles during the week, and consumed 20 litres of fuel in the process, your calculation would look like this:
180/20 x 4.546 = 40.9 mpg
The figure you get is the one you’re out to beat.
Walking, cycling, and catching public transport are easily the best ways to save fuel. But they’re not very handy if you have to get the kids to school, get yourself across town for work, and then cart home a week’s worth of groceries. Cars are an important part of our lives and, for many of us, it’s just not practical to go without them.
Planning your trips, with the alternatives to driving in mind, is the next best thing. It’s easy to hop in the car and head to the corner store, but you could just as easily walk. When the engine is cold, it uses much more fuel in the first five miles, so small trips are particularly costly. If you’re out for groceries, perhaps you can swing by the DIY shop too. Jump on the bus on days when you don’t need the car after work. Carpool with colleagues who live in your area.
It’s easier said than done, but avoid rush hour if you can. Your car will use more fuel in low gear, so stop-start traffic is a real drain on your fuel tank. A little planning will help you dodge any gridlock. Radio updates can keep you up-to-date with any emerging traffic problems, or you can download a smart phone traffic app. Try to drive as smoothly as possible when you are stuck in traffic. Accelerate gradually and use the brakes sparingly. Starting from a dead stop requires higher revs and greater fuel consumption.
Aerodynamics is one of the biggest factors in fuel consumption, especially on the motorway. A sleek, slippery car will consume less fuel than a rough and boxy one. Most of us don’t have a Lotus, though, so here’s some simple things you can do to reduce your drag. A good rule of thumb: anything that sounds like the wind is costing you money.
The most obvious thing to do is roll up the windows. The air rushing into your car pushes on the rear window and effectively turns it into a parachute. While it won’t stop you in a drag race, it will cost you a whole bunch. Open the vents to get fresh air in the car. This is good practice anyway—air-conditioning uses a good deal of electricity, and a car’s electricity is generated by the engine. Only using it when the weather is hot will save up to 10% on your fuel costs.
Remove your roof racks and boxes when you’re not using them. It’s a bit of a chore, but five minutes with a spanner could save you up to 20% on fuel over a year.
Extra weight uses extra fuel. On average, every 50 kg adds 2% to our fuel consumption. Naturally, the heavier an item is, the less likely we are to take it out of the car. Music and sports equipment, garden supplies, and workshop tools often clutter up boots long after we’ve forgotten why we had them there. But if you don’t need it, ditch it.
Here’s something else we don’t often consider—it takes fuel to carry fuel. Maintaining only half a tank of fuel cuts a chunk out of the car’s overall weight, and saves fuel accordingly.
Keeping your car in good condition is one of the best ways to make significant fuel savings over the long run. Make sure you drop your car in for its scheduled services. Proper wheel alignment, clean oil and air filters, and reliable spark plugs not only ensure your motor lasts longer, but improves mileage by up to 4%.
Taking a few moments every other week to check your tyre pressure saves an additional 2% of your fuel. Don't know what your tyre pressure should be? Have a look on the edge of the driver’s door, or in the car's manual.
All the tips we’ve looked at so far add up to some impressive savings on your fuel consumption, but the biggest savings are made in your driving style. Essentially, the advice is this—patient, careful drivers save considerable amounts of fuel. Dropping from 80 mph to 70 mph on the motorway uses 25% less fuel. Slowing from 70 mph to 60 mph on smaller roads saves another 10%. Using cruise control on a freeway will save some fuel, but turn it off for urban driving. It’s only works on long, flat surfaces.
Higher gears use less fuel, so moving up whenever possible is best. Your RPM needn’t be especially high, either. Moving up a gear at 2,500 RPM in petrol-fuelled cars, and 2000 RPM in diesel-fuelled ones delivers the most efficiency.
Braking uses energy, but spends it as heat. It’s like opening your home’s windows when you have the fire on. You’ve burnt the fuel, but didn’t get any benefit out of it. Driving smoothly in traffic—slowing early for traffic lights or approaching a queue—means you may not have to stop at all and makes the most of the fuel you do use.
There are a few controversial tips out there which you should approach with caution. Some will advocate coasting down hills to maximise fuel economy. While this certainly works to lower your fuel consumption, it can also be dangerous. Staying in control of your vehicle is the most important thing. In part, that means being ready to accelerate to avoid a hazard.
Others suggest turning off your engine when you are stuck in traffic. This is fine, but choose your moments. Unless your car has a stop/start system, stopping the engine at the lights will use more fuel to restart and will put strain on your battery and starter motor.
Otherwise, only stop the engine if you expect to wait for more than three minutes, the engine is warm from twenty minutes of driving or more, and you know that your battery is in good condition.