In addition to my Hyper-Miling driving techniques that I have posted about to save fuel, I also got to thinking about what my MPG might be if I simply shut the engine off while at a stoplight or other traffic condition that prevents you from moving very much.
Some extreme hyper-milers actually do this and claim to increase MPG by 70%.
I decided not to actually shut my engine off every time I was at a stoplight because this would put an excessive amount of wear and tear on the starter motor.
But I did want to find out what my true MPG would be if I could do that without wearing out the starter.
The first thing I did was find out how much gas my Xterra uses while idling and not moving.
According to the dealership and the service manual the average fuel consumption while idling is 0.6 gallons per hour.
There is a small amount of variation because of things like running the AC, having the headlamps turned on which pulls more power from the alternator, or the engine simply being cold and not warmed up yet.
Anyway, 0.6 gallons per hour translates to 1.28 ounces per minute of engine idling.
This is a significant amount of fuel if you're idling a lot and not moving, such as in heavy city traffic.
To determine the possible MPG I could get if I shut the engine off at every stoplight I counted the seconds I was idling while stopped at a traffic light.
There is a lot of variation between traffic lights. Some are as short as 20 seconds while a few in the town I live in were as long as 90 seconds.
I just completed my experiment today.
In the recent experiment I idled at a full stop for a total of 25 minutes, which includes the times I was stopped at traffic lights and the 5 minutes I let it idle after a cold start.
With 25 minutes idling with an average consumption of 1.28 ounces per minute this meant I consumed 32 ounces of fuel while not moving during this experiment.
The total miles driven during this experiment was 65.35 miles from the last fill-up.
It took 3.09 gallons to top off my tank after this experiment.
The 32 ounces consumed during the estimated idling time is 1/4 of a gallon.
So I took the 3.09 gallons and deducted the 0.25 gallons consumed while idling.
According to the math I consumed 2.84 gallons while actually in motion for the 65.35 miles I drove.
Now dividing 65.35 miles by 2.84 gallons equals 23.01 MPG, and this is city MPG I drove, not highway. My average speed during this experiment was about 35MPH with a high of 50MPH and a low of 20MPH. It also includes my running the AC and using the 4WD for the few miles of dirt road I travel when I go out.
Since the naturally aspirated V6 that is in my Xterra is rated 14 MPG city, this means that if I were to shut off my engine while stopped at a traffic light, combined with my hyper-miling driving techniques, I would increase my MPG by 64.36% above the EPA 14 city, which is not far off from the 70% claimed by other people who do this.
I did some checking and it turns out that most hybrids already have this stop-start system, and in 2020, Toyota, Ford, and BMW have added a stop-start system to their vehicles in an effort to save fuel when stopped at traffic lights.
Maybe one day there will be an aftermarket system available that could be installed in our older cars, because as gas prices rise I am sure all of us want to save money.
Some extreme hyper-milers actually do this and claim to increase MPG by 70%.
I decided not to actually shut my engine off every time I was at a stoplight because this would put an excessive amount of wear and tear on the starter motor.
But I did want to find out what my true MPG would be if I could do that without wearing out the starter.
The first thing I did was find out how much gas my Xterra uses while idling and not moving.
According to the dealership and the service manual the average fuel consumption while idling is 0.6 gallons per hour.
There is a small amount of variation because of things like running the AC, having the headlamps turned on which pulls more power from the alternator, or the engine simply being cold and not warmed up yet.
Anyway, 0.6 gallons per hour translates to 1.28 ounces per minute of engine idling.
This is a significant amount of fuel if you're idling a lot and not moving, such as in heavy city traffic.
To determine the possible MPG I could get if I shut the engine off at every stoplight I counted the seconds I was idling while stopped at a traffic light.
There is a lot of variation between traffic lights. Some are as short as 20 seconds while a few in the town I live in were as long as 90 seconds.
I just completed my experiment today.
In the recent experiment I idled at a full stop for a total of 25 minutes, which includes the times I was stopped at traffic lights and the 5 minutes I let it idle after a cold start.
With 25 minutes idling with an average consumption of 1.28 ounces per minute this meant I consumed 32 ounces of fuel while not moving during this experiment.
The total miles driven during this experiment was 65.35 miles from the last fill-up.
It took 3.09 gallons to top off my tank after this experiment.
The 32 ounces consumed during the estimated idling time is 1/4 of a gallon.
So I took the 3.09 gallons and deducted the 0.25 gallons consumed while idling.
According to the math I consumed 2.84 gallons while actually in motion for the 65.35 miles I drove.
Now dividing 65.35 miles by 2.84 gallons equals 23.01 MPG, and this is city MPG I drove, not highway. My average speed during this experiment was about 35MPH with a high of 50MPH and a low of 20MPH. It also includes my running the AC and using the 4WD for the few miles of dirt road I travel when I go out.
Since the naturally aspirated V6 that is in my Xterra is rated 14 MPG city, this means that if I were to shut off my engine while stopped at a traffic light, combined with my hyper-miling driving techniques, I would increase my MPG by 64.36% above the EPA 14 city, which is not far off from the 70% claimed by other people who do this.
I did some checking and it turns out that most hybrids already have this stop-start system, and in 2020, Toyota, Ford, and BMW have added a stop-start system to their vehicles in an effort to save fuel when stopped at traffic lights.
Maybe one day there will be an aftermarket system available that could be installed in our older cars, because as gas prices rise I am sure all of us want to save money.