Anyone using Premium
JK Enthusiast
Joined: Apr 2007
Posts: 373
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From: Seattle, WA
Always use 87. Jeep always recommend to use only 87 octaine gasoline.
Owner's Manual P.321 says the engine is designed to use 87 octaine gasoline and says NOT to use premium gasoline. It says "The use of premium gasoline is NOT recommended... in some circumstances may result in poor performance..."
Owner's Manual P.321 says the engine is designed to use 87 octaine gasoline and says NOT to use premium gasoline. It says "The use of premium gasoline is NOT recommended... in some circumstances may result in poor performance..."
JK Enthusiast
Joined: Dec 2006
Posts: 176
Likes: 0
From: Southpark, CO
Premium fuel is a waste of money in vehicles that do not require it. Premium fuel has a higher octane content required by high compression engines. Octane resists the auto-ignition of fuel.
Octane levels here in Denver are 2 points lower than most places because standard octane levels are not required due to the elevation. Less air = more resistance to auto-ignition = lower octane requirement.
Octane levels here in Denver are 2 points lower than most places because standard octane levels are not required due to the elevation. Less air = more resistance to auto-ignition = lower octane requirement.
Last edited by Old_School; Apr 22, 2007 at 06:18 PM.
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JK Enthusiast
Joined: Sep 2006
Posts: 344
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From: lake worth fl
here 2 posts from our own fourm.I think this will say it all..
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I run exclusively 87 octane. Higher octane gas is not cleaner and in fact is slightly less powerful than lower octane gas. This is because more alcohol is mixed to give it the higher octane and alcohol is less powerful than gasoline. This is why ethynol cars get less mpg than cars that run on gasoline - alcohol is an inherently less powerful substance.
You will know if you need a higher octain if your car does one of two things: pings or knocks after while your engine is running (gurgling sound) or diesels after you durn it off. If it runs smooth, the octane is just fine. My '02 Thunderbird didn't like 87 octane, and it would run good on about 90. However, I was too cheap to use 90 octane, so I just put up with a slight "gurgling" on acceleration in hot weather. The Jeep JK runs on 87 no problem.
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04-20-2007, 02:27 PM #12
berg
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Join Date: Apr 2007
Location: Southern NJ
Posts: 15
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I have worked in refineries for 17 years. There are a lot of misconceptions about gasoline.
Higher octane does not mean more powerful. It is a indicator of it ability to resist detonation. Which means it can be compressed more before you get engine knock. An engine designed to run on 87 octane gains no additional power from a higher octane. In fact with computor control and engine knock sensors you may ("MAY," I said) get satifactory performance from a lower octane than recomended.
85 octane is not to be confused with E85 ethanol blend. E85 designates a percentage of ethanol alcohol. The octane of E85 can be 87 or higher.
This next statement will most likely get me some arguments.
"All gasolines are the same". Refineries routinely ship gasoline stocks from one producer to another as each has its needs. I originally thought that that being the case, then each manufacturer alters the gasoline mix with their particular additives.
I found out differient when working at an oil terminal where Sunoco, Gulf, Exxon and some independant gasoline companies were filling their tankers at the same loading rack. At the rear of the terminal were smaller additive tanks labeled with each companies name. I thought "there's the diffierence" until I saw that each tank had the same chemical abstract (CAS) number. So all of the additives were the same. A terminal operator showed me that mixing rate of the additives to the gasoline was the same for each brand.
So, in a nutshell, buy the octane that is recommended at the best price you can find. Gas moves so quickly that nobody has old gas lying in ther tanks.
Biggest warning that I can provide is don't buy gas from a station while it is getting filled up itself from a tanker. The filling process can stir up sediment in the storage tanks and if the station does not have proper filters on their pumps, some can wind up in your tank. Come back a few hours later to allow it to settle.
Now sombody ask me about motor oil.
__________________
Berg from Jersey
Steel blue 2 dr X
Soft top, Auto
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I run exclusively 87 octane. Higher octane gas is not cleaner and in fact is slightly less powerful than lower octane gas. This is because more alcohol is mixed to give it the higher octane and alcohol is less powerful than gasoline. This is why ethynol cars get less mpg than cars that run on gasoline - alcohol is an inherently less powerful substance.
You will know if you need a higher octain if your car does one of two things: pings or knocks after while your engine is running (gurgling sound) or diesels after you durn it off. If it runs smooth, the octane is just fine. My '02 Thunderbird didn't like 87 octane, and it would run good on about 90. However, I was too cheap to use 90 octane, so I just put up with a slight "gurgling" on acceleration in hot weather. The Jeep JK runs on 87 no problem.
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04-20-2007, 02:27 PM #12
berg
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Join Date: Apr 2007
Location: Southern NJ
Posts: 15
--------------------------------------------------------------------------------
I have worked in refineries for 17 years. There are a lot of misconceptions about gasoline.
Higher octane does not mean more powerful. It is a indicator of it ability to resist detonation. Which means it can be compressed more before you get engine knock. An engine designed to run on 87 octane gains no additional power from a higher octane. In fact with computor control and engine knock sensors you may ("MAY," I said) get satifactory performance from a lower octane than recomended.
85 octane is not to be confused with E85 ethanol blend. E85 designates a percentage of ethanol alcohol. The octane of E85 can be 87 or higher.
This next statement will most likely get me some arguments.
"All gasolines are the same". Refineries routinely ship gasoline stocks from one producer to another as each has its needs. I originally thought that that being the case, then each manufacturer alters the gasoline mix with their particular additives.
I found out differient when working at an oil terminal where Sunoco, Gulf, Exxon and some independant gasoline companies were filling their tankers at the same loading rack. At the rear of the terminal were smaller additive tanks labeled with each companies name. I thought "there's the diffierence" until I saw that each tank had the same chemical abstract (CAS) number. So all of the additives were the same. A terminal operator showed me that mixing rate of the additives to the gasoline was the same for each brand.
So, in a nutshell, buy the octane that is recommended at the best price you can find. Gas moves so quickly that nobody has old gas lying in ther tanks.
Biggest warning that I can provide is don't buy gas from a station while it is getting filled up itself from a tanker. The filling process can stir up sediment in the storage tanks and if the station does not have proper filters on their pumps, some can wind up in your tank. Come back a few hours later to allow it to settle.
Now sombody ask me about motor oil.
__________________
Berg from Jersey
Steel blue 2 dr X
Soft top, Auto
JK Jedi
Joined: Feb 2007
Posts: 7,568
Likes: 3
From: Denver, CO
Wasn't this discussed like 3 days ago? Search people.
But to add to the conversation, I find it very interesting that people do this. I think its the perception that all new vehicles need the highest octane fuel. It's almost like the oil inudstry has duped the public ( in general) into thinking that new vehicles require it. Stupid public.
But to add to the conversation, I find it very interesting that people do this. I think its the perception that all new vehicles need the highest octane fuel. It's almost like the oil inudstry has duped the public ( in general) into thinking that new vehicles require it. Stupid public.
Last edited by JackMac4; Apr 22, 2007 at 06:36 PM.
