Would we get better mileage runing 1/4 tank than always filling up? - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Go Back   Fuelly Forums > Fuel Talk > General Fuel Topics
Search Today's Posts Mark Forums Read Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 11-09-2007, 06:36 AM   #1
Registered Member
 
DarbyWalters's Avatar
 
Join Date: Oct 2007
Posts: 376
Country: United States
Would we get better mileage runing 1/4 tank than always filling up?

Just wondering what the weight of the extra, in my case 15 gallons, fuel does to our mileage...? If diesel fuel is 7.206#/gallon...would the 108# savings benefit mpg much?
__________________

__________________
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter



DarbyWalters is offline   Reply With Quote
Old 11-09-2007, 08:48 AM   #2
Registered Member
 
zpiloto's Avatar
 
Join Date: Mar 2006
Posts: 1,225
Country: United States
Quote:
Originally Posted by DarbyWalters View Post
Just wondering what the weight of the extra, in my case 15 gallons, fuel does to our mileage...? If diesel fuel is 7.206#/gallon...would the 108# savings benefit mpg much?

I don't think it quantifiable in terms of the equipment we have to measure. The EPA says to remove excess weight to increase FE but I don't think 100# on a 3000# will show up. The lighter the car the better I guess. It definately helps with acceleration. Might want to do a search. I did some playing around with this in a Mazda 626 which has a 15 gallon tank and did several tanks with 4 gallons. No noticeable increase if FE. Plus it was a hassel to fill every 2-3 days. YMMV
__________________

zpiloto is offline   Reply With Quote
Old 11-09-2007, 09:11 AM   #3
Registered Member
 
Join Date: Nov 2007
Posts: 1,460
Country: United States
Location: north east PA
I had noticed that I got better milage towards the end of a tank with the Prius, so I tried only filling it part way. It seemed to help, but my technique was also improving, tires wearing, etc. I may try it again with the Ranger.

A co-worker that moved up from the south pointed out that they couldn't partially the tank. The humidity could lead to rusting in the tank.
trollbait is offline   Reply With Quote
Old 11-09-2007, 09:13 AM   #4
Registered Member
 
skewbe's Avatar
 
Join Date: Jan 2007
Posts: 771
Country: United States
It really depends how you drive. If you are good at staying off the brakes (including engine braking) it won't make much difference, you will simply glide about 1/30 farther than normal for a given car (and have to accelerate 1/30 more).

If you are wasting a lot of energy braking then you will get about 1/30 worse mpg with a full tank. Note the 1/30 is 100 lbs of fuel in a 3000 lb car. A smaller car/fuel tank will have a different ratio.
__________________
Standard Disclaimer
skewbe is offline   Reply With Quote
Old 11-09-2007, 09:24 AM   #5
Registered Member
 
Join Date: Aug 2007
Posts: 313
Country: United States
what skewbe said plus hills of any size...
__________________
2TonJellyBean is offline   Reply With Quote
Old 11-09-2007, 09:54 AM   #6
Registered Member
 
Hateful's Avatar
 
Join Date: Nov 2007
Posts: 321
Country: United States
Send a message via AIM to Hateful
I did see a gain carrying less gas,but after all the other measures taken since then, I didn't see the same loss when I filled all the way up again. It's cold now and I don't like getting out of the warm car to pump gas. Also the pump stops are just adding to low FE parking lot driving.
Hateful is offline   Reply With Quote
Old 11-09-2007, 10:03 AM   #7
Registered Member
 
Danronian's Avatar
 
Join Date: Aug 2007
Posts: 652
Country: United States
Quote:
Originally Posted by Hateful View Post
Also the pump stops are just adding to low FE parking lot driving.
That's what I was thinking. Most times during rush hour there is also lines at the pumps where I live, so that would just make mores stop-go driving. I think on a car with a large tank, this issue of not filling up all the way could be helpful, but with a mere 10 gallon tank on my civic, I don't think there would be much difference.
__________________


On the never-ending quest for better gas mileage...
Danronian is offline   Reply With Quote
Old 11-09-2007, 10:14 AM   #8
Registered Member
 
Join Date: Aug 2007
Posts: 313
Country: United States
Just do the math on if the weight affects things...

6.2 pounds per gallon (premium is 6.35 PPG)

Added mass affects acceleration and climbing. As a heavy cyclist I can tell you for a fact, that mass and hills is bad. What you lose going up always exceeds what you gain going down, both in time and energy.
__________________
2TonJellyBean is offline   Reply With Quote
Old 11-09-2007, 10:25 AM   #9
Registered Member
 
palemelanesian's Avatar
 
Join Date: Apr 2013
Posts: 364
Country: United States
Analyzing my commute since April (270 data points)yields these results:

Full tank: 54.5 mpg
3/4 tank: 54.7 mpg
1/2 tank: 54.7 mpg
1/4 tank: 54.5 mpg
empty: 53.8 mpg

I try to run the maximum per tank, and minimize the number of fillups.
palemelanesian is offline   Reply With Quote
Old 11-09-2007, 10:57 AM   #10
Registered Member
 
1993CivicVX's Avatar
 
Join Date: Aug 2007
Posts: 1,066
Country: United States
Send a message via AIM to 1993CivicVX
Quote:
Originally Posted by DarbyWalters View Post
Just wondering what the weight of the extra, in my case 15 gallons, fuel does to our mileage...? If diesel fuel is 7.206#/gallon...would the 108# savings benefit mpg much?
No, but you might get worse due to increased vapor loss.
__________________

__________________
three stripes the charm!

Car mods are overrated. Just gotta adjust that nut behind the wheel for best mpg.



Forget about World Peace...Visualize using your turn signal.
1993CivicVX is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
API - Revisted? shaneeckert Fuelly Web Support and Community News 1 09-25-2010 03:41 PM
CRX HF Transmission Rebuild GasSavers_DaX General Fuel Topics 35 09-15-2010 04:37 AM
Competition Averages rh77 General Fuel Topics 16 08-06-2007 10:45 AM
Funny comments from women I know. Compaq888 General Discussion (Off-Topic) 10 02-11-2007 10:29 PM
"active" aero grille slats on 06 civic concept MetroMPG General Fuel Topics 21 01-03-2006 01:02 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 12:23 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.