Super poor gas milage help - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 04-01-2011, 09:31 AM   #1
Newb
 
Join Date: Apr 2011
Posts: 13
Unhappy Super poor gas milage help

I have a 1990 wrangler. I just bought it.2.5 liter 4cyl. Manual 5 speed trans. 31x10.5x15 tirers i think i am only getting about 10 miles to the gallon with this thing. It has a new tune-up on it. It runs great. Is this normal or do i have some other problem here? Thank you.

jpirrone is offline   Quote Quick Reply
Old 04-01-2011, 09:38 AM   #2
Jeeper
 
NHrubicon's Avatar
 
Join Date: Jul 2010
Location: New Hampshire
Posts: 844
Images: 1
You should be getting better mileage, but those wide/large tires are going to throw you off. The speedometer and odometer probably isn't geared for that large (31") so your math is incorrect. I have a 94 with the same engine, ran same size tires and took them off after 2 summers of fighting with it trying to get up to highway speed between trails. Went back to narrow tires and smaller rims (had rubicon MOAB rims, way too heavy).
Not sure what my gas mileage is-have only run it probably 12-15 trails locally and only filled the gas tank once! This summer when it comes out from under the tarp it will get filled up again and I'll try to track the mileage. You 'should' be getting 15 mpg or better if you aren't heavy footed on the skinny pedal!

NHrubicon is offline   Quote Quick Reply
Old 04-01-2011, 10:19 AM   #3
Newb
 
Join Date: Apr 2011
Posts: 13
Thanks for the reply.thats what i was wondering about,and your right about fighting to reach highway speed....
jpirrone is offline   Quote Quick Reply
Old 04-01-2011, 11:27 AM   #4
Jeeper
 
Join Date: Aug 2008
Location: Alabama
Posts: 86
Your speedo shouldn't be too far off, though. I have the same setup and my speedo is between 3 and 4 MPH off. Still, I get 18 mpg, (mostly city and back road driving), with 31's and the change from 30's was hardly noticeable. If you have a lift, however, I'm convined that driveshaft alignment can affect fuel mileage if U-joint angles are great. The more you throw the drive shaft off angle the harder they are to turn and I think it shows up in a reduction of mpg.
nzpete is offline   Quote Quick Reply
Old 04-01-2011, 11:41 AM   #5
Jeeper
 
Join Date: Mar 2011
Posts: 22
I only average 18 from my stock JK. With modifications
I can see where you would get much less, but you may be going much farther than you think on those big tires. If my math is right, you are going about 10 inches per tire revolution farther, about 10%. That at least bumps you up to 11mpg.
__________________
Whoa Black Betty... bam-ba-lam
Black 2010 Jk Sport...
2 door Auto...
Bone Stock
jp4fun is offline   Quote Quick Reply
Old 04-01-2011, 12:30 PM   #6
Newb
 
Join Date: Apr 2011
Posts: 13
The body also has a 3 inch lift.i never thought that would have a afect on gas milage..
jpirrone is offline   Quote Quick Reply
Old 04-01-2011, 12:43 PM   #7
Jeeper
 
jstone326's Avatar
 
Join Date: Mar 2011
Location: New York
Posts: 749
Quote:
Originally Posted by jp4fun View Post
I only average 18 from my stock JK. With modifications
I can see where you would get much less, but you may be going much farther than you think on those big tires. If my math is right, you are going about 10 inches per tire revolution farther, about 10%. That at least bumps you up to 11mpg.
Except bigger wheels = larger contact area with the road = more friction = less mpgs...at least that's how I understand it

__________________
Drive it like you rented it, not like you stole it. Cus if you stole it, you'd be driving 5 mph below the speed limit and using your turn signals.
jstone326 is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may 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
super 35 price nelson08 TJ General Discussion Forum 18 03-23-2011 09:08 PM
the '80s thread stangfreak Off-Topic 215 10-02-2010 04:56 PM
Sailcloth vs regular soft top & super doors? Loo TJ General Discussion Forum 5 03-04-2010 07:17 PM
for my next trick: a super 35 kit + regear brjeep TJ General Discussion Forum 11 11-16-2009 09:25 AM
Help with gearing, gas milage, what next?? 288sunny TJ General Discussion Forum 13 09-17-2009 12:01 AM



Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 01:50 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC