Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now

Reply  Post New Thread
Submit Tools LinkBack Thread Tools
Old 06-22-2008, 09:05 PM   #1 (permalink)
Master EcoModder
wagonman76's Avatar
Join Date: Jun 2008
Location: Northwest Lower Michigan
Posts: 1,006

Red Car - '89 Chevrolet Celebrity CL 4 door
Team Chevy
90 day: 36.47 mpg (US)

Winter Wagon - '89 Pontiac 6000 LE Wagon
90 day: 28.26 mpg (US)
Thanks: 8
Thanked 17 Times in 16 Posts
Filling the tank with repeatabilty

People usually say to get an accurate reading, you gotta use the same pump at the same station all the time. I think it is because there is a huge difference in pumping speeds between stations.

So heres what I have been doing for years to get repeatable results over pumps from anywhere. And it works really well.

First of all, if the car is sitting considerably nose up or down, itll affect the fill. But I only know of a couple of stations like that, and it only affects me 1 mpg one way or the other. Next tank averages out. I tend to avoid those stations unless the price is better than the others.

Then what I do is always pump the same speed. Which is about 0.1 gallon per second, I just imagine a clock ticking in my head as I watch the gallons readout. Then when it kicks off, I pump about half that speed till it kicks off again, and it usually does in about half a gallon. Then I call it good.

Actually, this started back with one of my old cars, when I had a problem pumping the gas too fast or itd trip the spillover valve and stop the pump. Then I just got used to pumping slower and once I started really logging mpg it came in handy.

Does anyone else do this? Or does anyone else do anything better?


Winter daily driver, parked most days right now

Summer daily driver
  Reply With Quote
The Following User Says Thank You to wagonman76 For This Useful Post:
j12piprius (02-22-2011)
Alt Today
Popular topics

Other popular topics in this forum...

Old 06-22-2008, 11:51 PM   #2 (permalink)
EcoModding Lurker
threeta's Avatar
Join Date: Jun 2008
Location: Auckland, nz
Posts: 8

con - '98 Ford Falcon GLi
90 day: 18.6 mpg (US)

aye333 - '05 Audi a3 2.0
90 day: 23.78 mpg (US)

lego - '96 honda logo
90 day: 37.6 mpg (US)

del - '03 ford Falcon xr6T
90 day: 19.13 mpg (US)

jak - '08 mazda atenza sp25
90 day: 27.06 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
my car seems to suffer from this - sometimes the gauge is stuck way over full, and others at about7/8 full. It seems the load in the car stuffs up the fill as well. It makes for some great mpg numbers - good and bad depending on the previous fill. I always just stop at the first shut off - but i'll experiment with your slow fill method next tank or two and see if it helps - i'll be back in a month or 2 - only ever fill up every 3 or so weeks!!!
  Reply With Quote
Old 06-23-2008, 12:34 PM   #3 (permalink)
Ecomod noob
zjrog's Avatar
Join Date: Feb 2008
Location: Tooele, UT
Posts: 412

ZJ - '95 Jeep Grand Cherokee Laredo Upcountry
90 day: 20.57 mpg (US)

Neon - '03 Dodge Neon SE
90 day: 33.46 mpg (US)

S'Crew - '02 Ford F150 Supercrew XLT
90 day: 16.4 mpg (US)

Ranger - '90 Ford Ranger
Last 3: 28.02 mpg (US)

Not the Jeep - '03 Dodge Neon SE
90 day: 34.11 mpg (US)
Thanks: 7
Thanked 15 Times in 10 Posts
Sometimes my Neon tank needs to "burp". So I've taken to bumping the car pretty hard after the nozzle shuts off. Almost always good for another 1.5 gallons...
When it comes to Heroes, RENEGADES are mine!
  Reply With Quote
Old 06-23-2008, 01:03 PM   #4 (permalink)
Mr. Blue Tape
azraelswrd's Avatar
Join Date: Jun 2008
Location: Fresno, CA
Posts: 345

AzxA - '06 Scion xA
90 day: 42.72 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
Wow, I didn't know about this. I guess I've been lucky that I prefer to not only use the same station but the same pump. Does it matter if I pump the gas manually or use the clip on the handle? I usually leave the pump going automatically and wash my windows or check my tires in the meantime.

My 5 pillars of fuel efficiency:
  • driving style
  • aerodynamics
  • tires
  • weight reduction
  • engine maintenance
  Reply With Quote
Old 06-23-2008, 01:07 PM   #5 (permalink)
Join Date: May 2008
Location: Alexandria, MN
Posts: 684

Volt12 - '12 Chevy Volt base
Thanks: 0
Thanked 12 Times in 10 Posts
My car can't even take full speed on the nozzle.. it just clicks off right away.. so i do the following..

The nozzle always goes in a certain way.. otherwise it clicks off early on my car.. seems the filler neck is just slow draining..

I always use the same station.. when I can the same pump.. but all there pumps are the same type.. I set the gas nozzle "cruise control" to the first little notch on the nozzle... let it fill, then when it clicks off I just trickle it in (half of the first notch on the nozzle) till it clicks off again.. the i quit.. It never over fills it but I found that if i didn't trickle it in at the end id get off fills..like .5 gallons difference sometimes.. at 50 mpg that can be a big difference.

  Reply With Quote
The Following User Says Thank You to ebacherville For This Useful Post:
j12piprius (02-22-2011)
Old 06-24-2008, 05:51 PM   #6 (permalink)
Master EcoModder
Join Date: Jun 2008
Location: NorCal
Posts: 451
Thanks: 1
Thanked 40 Times in 26 Posts
I don't think we can 'learn' much from taking mpg readings from one tank of fuel... sure, we might get bragging rights that justify something to somebody (may only ourselves) but we simply can't do accurate enough filling in one tankful to defiatively learn weather or not that latest driving technique or do-dad made 1mpg difference or not... the sample size is too small, the equipment not accurate enough, and the environment is not controlled enough... that's the bad news.

The good news is this, so long as all the fuel from the pump goes into the tank, (not spilled on the ground) and the pump is measuring accurately (controlled calibrations performed (monthly?) by the State Board of Weights and Measures) averaging takes care of the uncertainty of 'how much fuel did I just burn?'. Through averaging you will always get an answer to the question "what's my mpg?" your real fuel usage, which is what you care about anyway.
  Reply With Quote
Old 06-26-2008, 07:09 PM   #7 (permalink)
EcoModding Lurker
Join Date: May 2008
Location: western Colorado
Posts: 59

ScabbySentra - '93 Nissan Sentra SE
90 day: 44.37 mpg (US)
Thanks: 2
Thanked 7 Times in 6 Posts
Keep in mind that the error is proportional to how much you put in the tank. In other words, an error of +/- 0.5 gallons will be 5% if you're putting in 10 gallons, as compared to 10% if you only need 5 gallons to fill it.

Temperature seems to make a notable difference, too. I try to fill at the same time (preferably when it's cool outside) so that doesn't make so much difference.
  Reply With Quote
The Following User Says Thank You to jim-frank For This Useful Post:
j12piprius (02-22-2011)
Old 06-26-2008, 09:45 PM   #8 (permalink)
cookie96civic's Avatar
Join Date: Jun 2008
Location: Zeeland, Michigan
Posts: 27

FumeSniffer - '96 Honda Civic DX
90 day: 46.19 mpg (US)

Big Gulp - '06 International 8600-375 Twin Turbo
90 day: 7.15 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Make sure you measure (roughly) the amount of nozzle in the filler neck. Some nozzles are more curved than others and some are straight, lastly don't jam the nozzle all the way in the filler, this really distorts the differences between nozzles. ---nozzle rolls off the fingers nice once you've typed it many times.
  Reply With Quote
Old 06-27-2008, 08:32 AM   #9 (permalink)
Master EcoModder
tasdrouille's Avatar
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 86 Times in 57 Posts
I use the same pump as often as possible, but it's not always possible. I just fill her till it clicks, and then I go for a second click just it case it clicked early. Usually the second click comes in almost instantaneously. But anyway, in the long run all those variations even up.

www.HyperKilometreur.com - Quand chaque goutte compte...
  Reply With Quote
Old 06-29-2008, 07:25 PM   #10 (permalink)
Renaissance Man
Formula413's Avatar
Join Date: Jan 2008
Location: In the Northeast dreaming of the Southwest
Posts: 596

Aegean C - '17 Honda Civic LX
90 day: 41.77 mpg (US)
Thanks: 20
Thanked 31 Times in 24 Posts
Originally Posted by azraelswrd View Post
Does it matter if I pump the gas manually or use the clip on the handle? I usually leave the pump going automatically and wash my windows or check my tires in the meantime.
In Massachusetts they took those clips way from us. We are not to be trusted! Some people figured out that they could stick their gas cap in the handle to keep the nozzle open, so gas stations put up signs saying "do not stick any object in nozzle for continuous flow".


  Reply With Quote
Reply  Post New Thread

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Filling Up Full Tank Adds Unnecessary Weight Thus Reduces Mpg. dsq EcoModding Central 54 02-22-2011 05:33 PM
How to put 14.6 gal in a 13.2 gal tank! Z28WTW EcoModding Central 18 05-14-2009 08:41 PM
The acetone test trikkonceptz EcoModding Central 88 06-16-2008 11:27 PM
Gas tank size on '93 Civic DX hatch ? Cd EcoModding Central 0 06-06-2008 11:44 AM
First tank w SG homeworkhome53 Instrumentation 3 04-14-2008 12:57 AM

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com