91 octane - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 07-16-2012, 04:57 PM   #1
Jeeper
 
lucky4075's Avatar
 
Join Date: Jan 2010
Location: NY
Posts: 119
91 octane

Im not sure if this has been answered before but:

Would there be any long term effects or damage from running 91 octane as opposed to the 87 the owners manual says? I ask because the local gas station has ethanol free 91 now, and its really about the principle of putting pure gas into my tank for me. A mechanic that I trust very much said that it would be fine and that the owners manual says 87 because thats just the minimum you should ever put in there. I'm still a bit skeptical tho.

thanks

lucky4075 is offline   Quote Quick Reply
Old 07-16-2012, 05:04 PM   #2
Jeeper
 
brendend's Avatar
 
Join Date: Mar 2012
Location: colorado springs
Posts: 889
Images: 1
Higher is fine just don't go lower

brendend is offline   Quote Quick Reply
Old 07-16-2012, 05:10 PM   #3
Supporting Member

WF Supporting Member
 
schnutzy's Avatar
 
Join Date: Sep 2009
Location: ring side seats to the the country's largest circus
Posts: 28,190
Send a message via AIM to schnutzy
Quote:
Originally Posted by brendend View Post
Higher is fine just don't go lower
not quite.
running higher then recommended octane is not just fine.
the 91 does not burn off as well in a motor designed to run on 87. as a result, it burns dirtier, and can cause carbon build up. that build up leads to a poor running engine, pinging, and all that fun stuff.
__________________
clinging on to sanity, one motorcycle at a time.
schnutzy is offline   Quote Quick Reply
Old 07-16-2012, 05:57 PM   #4
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 32,264
Images: 2
Higher octane is NOT fine. The higher the octane level, the harder the gasoline is to ignite and the slower it burns and the less well your engine will run with it. Not to mention higher octane level gasolines can leave more deposits behind since it doesn't burn as quickly or as easily as lower octanes do. The ONLY engines that can take advantage of higher amounts of octane are those that were designed for it with extra-high compression levels or who have excessive carbon deposits that raise the compression level which can make an engine ping.

What does octane do? The first thing it does NOT have or add is more power. Octane's SOLE purpose is to slow down/retard how easily the gasoline is ignited and reduce how easily it can be ignited prematurely from excessive compresson... which is why only higher compression engines require and benefit from higher levels of octane.
__________________
Gone wheeling, back late sunday...
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 07-16-2012, 07:16 PM   #5
Jeeper
 
zomby's Avatar
 
Join Date: Mar 2012
Posts: 157
here is some other info don't mix ethanol fuel with non ethanol fuel when that originally switched the mbte with e 10 the marine and small engine industry was in a panic with jelling in fuel tanks lines and in the carburetors. the stuff is nasty and still happens if you leave e 10 in stuff that is vented to the open atmosphere to long, if its vented to the open fuel is only good for no more then 3 weeks, it stinks and i hate having to clean it but i guess its my job and what id do
__________________
just got my fist jeep 3/3/12, we'll see how it goes
zomby is offline   Quote Quick Reply
Old 07-16-2012, 09:27 PM   #6
Jeeper
 
lucky4075's Avatar
 
Join Date: Jan 2010
Location: NY
Posts: 119
Yeah I'll stick to the regular 87 even though it has the crap in it. My gut thought it was a bad idea because of the slower/less complete burning etc.

I have mixed ethanol gas and pure gas before, all it would do is dilute it to almost no ethanol depending on how much pure gas you put in. When I do get the opportunity to get to the station near here that has pure 87 I usually wait until the jeep is below 1/4 tank.

lucky4075 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




Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 08:06 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