Now that you have a basic understanding of what happens to the energy in a car and how to manage it, it’s time to start working on your overall driving. Every car is different, and you are always driving in different conditions, so we are going to need to take out the guesswork.
The only way you can really know if you’re really saving gas or not is to have your usage measured. You can follow all of the tips you learn in this course and do them slightly wrong, saving nothing or even burning more gas. The only way to know if you’re doing it right is to check the mileage as you go.
The first “hypermilers” were just folks like you who wanted to save gas. They watched their MPG readouts, and they did more of what gave high MPG readings, and less of what gave low MPG readings. They experimented, they tried new things. When the new things lowered average fuel usage, they did those things more.
They basically took the scientific method and applied it to saving gas, and it worked. You can learn from them and the other eco drivers who came before you, and you can probably improve on what they did.
But you have to measure your mileage, or you’ll be flying blind.
The “Old School” Approach
Eco driving really isn’t new. People have been checking their MPG to save money for over a century. Before instant MPG readouts and gauges, the gas conscious driver would use this method (or similar) to get their mileage:
- Fill up your tank to the first click. No “topping off”. Or, if you want it to be super accurate, fill the the last little bit slowly until it can’t take any more and is literally up to the gas cap. Just don’t do this regularly, because “topping off” can cause problems if done too much.
- Reset your trip odometer (consult your manual if you’re not sure how to use it)
- Drive for a number of miles. The more, the better, but pay attention to what kind of driving you are doing (city, highway, etc).
- Fill up your tank again, to the first click, or otherwise do whatever you did the first time.
- Look at the number of miles on the trip odometer, divide that number by the number of gallons you just put in your car to get it full again.
- You now know how many miles per gallon you got, and if desired, can keep a log of MPG and type of driving for future reference.
What good does this do?
While this doesn’t give you your MPG from moment to moment, it does give you an idea of what kind of results your driving gets. If you drove with a “lead foot”, constantly on the gas hard, you’ll see lower numbers. If you took it easy, you’d see better miles. City miles would give lower numbers than the highway for gas vehicles.
Perhaps more importantly, drivers would watch for a big mileage reduction to know if their car needed work, such as a tuneup.
Using A Built-In MPG Display or Trip Computer
Most newer cars (2000 to present, upscale cars first, base packages later) have some form of builtin readout for fuel economy. If your car does not have this feature at all, don’t worry. I will talk about adding one in a later section.
For gas motors, there are two numbers you will want to monitor if possible:
- Average MPG (since last reset)
- Current MPG/Consumption
The above image is from a 2005 Acura MDX. It shows a half-circle gauge on the left and the “Avg” number toward the middle of the display. The half-circle shows the fuel efficiency the car is getting right now, while the “Avg” number shows the average since the computer was last reset.
Not every car will give you both numbers. Some will only give you the average number, and you might have to work your way through some menus to get it to display. Others will only give you one number at a time, and you have to use steering wheel buttons to switch between them.
I can’t cover every vehicle there is in this course, but I’d recommend looking at your owner’s manual for full details. Look for “Fuel Economy”, “MPG”, or “trip computer” in the index.
What To Do With These Numbers
The Average MPG is good to see if your driving behavior over time is working, kind of like the “old school” method. For example, if you’d like to measure your highway mileage, you’ll want to reset the average after you’re up to cruising speed and let it count your mileage over time until you exit the highway. If you want to measure your mixed real-world mileage, leave the average running for a few days without resetting it.
If your car doesn’t have the current consumption display (Instant MPG), you can still get this number by resetting the average frequently during driving. Be sure to NOT let the display and resetting it distract you from the road!
The instant/current consumption number is good for seeing what your present consumption is. When accelerating from a stop, you’ll see a really low number. Once you’re at cruising speed, you’ll see it rise. When decelerating, it should go really high, or even display “— MPG” if your car has cut off the fuel.
When you are driving and you see the current number dipping, you can ease up on the gas and watch it improve, or change some other aspect of your driving.
After a few drives (safely and carefully) monitoring your average and instant numbers, you will start to get an idea of how the numbers usually look and you’ll start seeing how your driving affects the numbers.
Once you reach this point, you are ready to start seriously improving your mileage.