More MPG at the pump

[Flandry]

A little while back, Brooklyn Bay posted an email he received from a friend on increasing fuel economy at the pump on Aldive's Quest thread. I thought I'd give this one a try:

4. If you look at the trigger, you'll see that it has three delivery settings: slow, medium, and high. When you're filling up, do not squeeze the trigger of the nozzle to the high setting. You should be pumping at the slow setting, thereby minimizing vapors created while you are pumping. Hoses at the pump are corrugated. The corrugations act as a return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapor which is being sucked back into the underground tank, so you're getting less gas for your money.

It's taken me several tanks to confirm the results, but this does seem to work. Near as I can tell, pumping gas at the slowest setting gave me an apparent average mpg increase of around 0.6%. My previous best mileage was 20.13 mpg. With no other changes, but the way I pump gas, I've achieved a new best of 20.32 mpg. Obviously this is a very small gain, and not a measure of actual increased fuel efficiency in my truck (I just got more of the gas I paid for). But it's free and easy and looks like it allows me to keep a little of the money I'd otherwise be giving to Big Oil.

 

[BrooklynBay]

Some states like NJ don't allow you to pump your own gas, so I guess this is good for most of the other states. Did you try any of the other things in that post?

 

[Flandry]

No. I always try to evaluate things individually to get the most reliable data and #4 was the easiest. However, I've always practiced #2, "If a tanker truck is filling the station's tank at the time you want to buy gas, do not fill up."

Thanks for posting the tips!

 

[bisjoe]

I've been running the first 10-12 gallons on fast, then slow it down because on my Ranger it will sometimes shut off before it's full at full speed. I'll have to try this suggestion and run slow all the time to see if it makes any difference. It does make sense.

 

[Charlie]

I always just go slow anyway, because it feels like you are getting more. And now, apparently actually are.

 

[Bill Kemp]

When its below 20 degrees I pump it as fast as it will go and where ever it stops...thats enough. Personal comfort doesnt know mileage. Warmer weather is the time for mileage considerations.

 

[Flandry]

Well, I've been testing number one:

1. Fill up your car or truck in the morning when the temperature is still cool.

And this seems to make no recognizable improvement in my gas mileage. I have to say, I'm surprised. I kept expecting to see a positive result but it never happened. Perhaps it takes a day/night temperature differential greater than the weather in my area has been capable of producing.

 

[Ranger Al]

Awesome idea, I'll give it a try when I fill up my tank. I just hope you are not doing that when I am waiting in line...

 

[sloppy2nds]

There is no way to know for sure using this method...too many variables. A slight variation in weather, taking roads with more hills etc will change gas mileage....often more than .6 %.

The only way you would even have a chance at knowing would be to fill up jerry cans, one full speed, one medium and one slow and see what the result is.

 

[Flandry]

There is no way to know for sure using this method...too many variables. A slight variation in weather, taking roads with more hills etc will change gas mileage....often more than .6 %.

You're right, there are unavoidable variables with this method. But I can tell you what I did to make things as consistent as possible:

• I tested using my work commute, driving the same roads with the same hills. My work schedule does not require driving during the rush hour periods.
• I drove below the speed limit, so slowing and speeding up was limited. I tried to keep my speed consistent as checked at the same waypoints I've used for prior testing.
• My driving style didn't involve hard accelerations or decelerations.
• I tested several tanks then averaged the results (in this case 6 tanks over six weeks).
• I used the same pump at the same gas station at about the same time of day each time I filled up.

I'll also say the weather was mild during the time of the testing.

I compared my previous averaged mpg figure with the averaged mpg figures from this test.