With gas prices soaring world wide, I figured it was time to share a bit of the knowledge of fuel efficiency that I’ve gained in the last couple of years at school. I hope you find something here that helps you save a bit of money.
Maintaining the correct air pressure in your tires can increase your gas mileage greatly. If your tires are 4 psi under the target pressure, your efficiency can drop by 3%. It will drop even more if you have a wider than normal tire. Your tires also lose over 1 psi per month depending on the age and condition of the tire, so checking the pressure regularly is a necessity.
Idling your car happens, if you are at a traffic light or behind someone turning then you’re going to have to idle. But if you know you are going to idle for more than 30 seconds, it is better to shut off your car and restart it. Modern cars are very efficient at starting, and it makes sense to shut off your engine if you aren’t going to be using it. Also, on cold mornings it is better for your gas mileage and engine to only idle for 20-30 seconds before driving easy until temperature is reached. The 20 or so seconds allows oil pressure to build. On older cars it was necessary to idle till temperature was reached, but with modern oils and fuel systems, this is no longer the case.
If you’re going down a long hill, it is sometimes possible to switch to neutral. This will work for you two ways, your car won’t be propelling itself, and you won’t be tempted to push the gas because you’ll be focusing on traffic around you.
Using the manufacturer’s recommended oil can improve your fuel efficiency by up to 5%. Normally a synthetic oil is recommended, but if not it’s best to go with the equivalent synthetic. Synthetic oils have lower viscosity and better lubrication properties than natural oils, your car will run much better with a synthetic under the hood.
If you are on the highway and don’t have to worry about traffic, it is much easier on your car to go 3 km/hr above and below your set point than you trying to get the speed right. Especially if you are on an undulating road where your speed might vary quite a bit.
Keeping to the speed limit on the highway or slightly below reduces the amount of aerodynamic drag on your car. Rolling resistance is linear with speed, so it is a factor at lower speeds where drag isn’t.
But aerodynamic drag is a proportional to the square of speed, this means if you are going 120 km/h vs. 100 km/h you can use 10-15% more fuel than if you go a little slower. This can be a major source of fuel efficiency problems.
I hope these tips keep your wallet full, and your car happy.