Anyone using Premium
JK Jedi Master
Joined: Mar 2007
Posts: 14,800
Likes: 374
From: Midwest City, OK
That is the strongest argument that I've read in this thread that 87 octane is fine. But, is it 87 octane at the pump? Media reports suggest that the number on the pump all too often has little bearing on what's actually in the tank.
JK Junkie
Joined: Jan 2007
Posts: 2,710
Likes: 0
From: AT LARGE somewhere in CT
I am with all of you on this thread that say 93 octane in the JK is a waste of money. My last car, a WRX, HAD to have 93 octane because of its high compression (due to tuning and turbo). I performed an experiment with the WRX once, where I ran 87 in it... the result? Piss-poor performance (and I mean BAAAAADDD). Never did it again.
The JK runs great on 87, is specifically tuned for 87, and will see no appreciable benefit in power OR fuel economy by upping the octane level... it's just not "efficient" enough to grab the extra energy potential of higher-octane fuel. Now, if you run a reprogrammer and make some significant mods to the engine, maybe that'd be a different story...
Just my $.02 (per gallon, x15).
JK Newbie
Joined: Mar 2007
Posts: 77
Likes: 0
That is the strongest argument that I've read in this thread that 87 octane is fine. But, is it 87 octane at the pump? Media reports suggest that the number on the pump all too often has little bearing on what's actually in the tank.
That is an entirely different argument and I doubt it's much to worry about if you stick to name brands and not Bubba's gas and go. Hopefully your state is regulating and inspecting accordingly. But I guess it is like that with anything you purchase and can't see it being made in front of you....ever wonder what goes on in the kitchen when you order a burger???
That is an entirely different argument and I doubt it's much to worry about if you stick to name brands and not Bubba's gas and go. Hopefully your state is regulating and inspecting accordingly. But I guess it is like that with anything you purchase and can't see it being made in front of you....ever wonder what goes on in the kitchen when you order a burger???
JK Jedi Master
Joined: Mar 2007
Posts: 14,800
Likes: 374
From: Midwest City, OK
...ever wonder what goes on in the kitchen when you order a burger???
As for octane--there has been plenty of media attention to the issue of octane rating of gas being lower than stated on the pump, despite state inspection systems and regardless of brand. If we are to accept that some JK-forum member(s?) experience improved gas mileage by using mid-grade or premium, it might explain why that happens for them. If the JK-forum member(s) who state that they experience improved mileage are mistaken or are just fabricating it, it's their loss only. I say leave them be.
JK Jedi
Joined: Jan 2007
Posts: 5,350
Likes: 2
From: Lacey, WA
From the Federal Trade Commission Consumer website:
Facts for Consumers:
The Low-Down on High Octane Gasoline
Are you tempted to buy a high octane gasoline for your car because you want to improve its performance? If so, take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual.
Again, the 14-yo is steering the Forum with bogus information. The feds would never lie to the public???
Trust us.....
Facts for Consumers:
The Low-Down on High Octane Gasoline
Are you tempted to buy a high octane gasoline for your car because you want to improve its performance? If so, take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual.
Again, the 14-yo is steering the Forum with bogus information. The feds would never lie to the public???
Trust us.....
JK Junkie
Joined: Dec 2006
Posts: 2,123
Likes: 1
From: Chattanooga, TN
It's unfortunate that you don't wish to share the details of your testing. ...Let me ask a few rhetorical questions,
1. What actions were taken to isolate the change in octane as the only change in the test configuration? IOW, were temperature, humidity, engine condition, etc. all controlled to ensure that they were identical during each pass of the test? A simple example of where a problem could occur: Run the test the first time with a cold engine using one fuel, then with a warm engine and the other fuel.
2. How many pass-throughs were made for the test? When there is no specific reason to determine a number, three is a generally accepted minimum number. Therefore, was each test repeated at least three times, and were idendital results obtained each time?
3. How were the fuels certified as to octane rating? Ideally, an independent lab would have tested and certified each fuel. If the rating was determined by layman simply buying fuel from two different pumps, then the results are suspect.
4. What specific controls were in place to ensure the accuracy and precision of the test measurement apparatus, including the elimination of environment factors impacting test measurements?
This is just a sampling of some of the issues that a proper, scientific testing regimen would consider. And, bottom line is, it won't provide real world results! That's because during real world operation, factors that are held constant in the laboratory test are in fact changing.
So, I'm not going to argue with someone who says he has measured his gas mileage and gets better with this octane or that. It's his dime (per gallon). I don't seriously accept that he's doing harm to the engine unless the octane is so low that he has serious knocking. And, at that, I believe that the JKs engine will adjust itself on the fly (again, I'd be interested in a technical description from someone knowledgeable of what's going in in the engine as the octane level of the fuel changes).
1. What actions were taken to isolate the change in octane as the only change in the test configuration? IOW, were temperature, humidity, engine condition, etc. all controlled to ensure that they were identical during each pass of the test? A simple example of where a problem could occur: Run the test the first time with a cold engine using one fuel, then with a warm engine and the other fuel.
2. How many pass-throughs were made for the test? When there is no specific reason to determine a number, three is a generally accepted minimum number. Therefore, was each test repeated at least three times, and were idendital results obtained each time?
3. How were the fuels certified as to octane rating? Ideally, an independent lab would have tested and certified each fuel. If the rating was determined by layman simply buying fuel from two different pumps, then the results are suspect.
4. What specific controls were in place to ensure the accuracy and precision of the test measurement apparatus, including the elimination of environment factors impacting test measurements?
This is just a sampling of some of the issues that a proper, scientific testing regimen would consider. And, bottom line is, it won't provide real world results! That's because during real world operation, factors that are held constant in the laboratory test are in fact changing.
So, I'm not going to argue with someone who says he has measured his gas mileage and gets better with this octane or that. It's his dime (per gallon). I don't seriously accept that he's doing harm to the engine unless the octane is so low that he has serious knocking. And, at that, I believe that the JKs engine will adjust itself on the fly (again, I'd be interested in a technical description from someone knowledgeable of what's going in in the engine as the octane level of the fuel changes).
JK Freak
Joined: Sep 2006
Posts: 511
Likes: 0
From: Saint Petersburg, Fl
hey FR have you ever heard of a "Placebo"? If you havent then im sure you will by the time you're a sophomore in high school. Putting premium in the take of a jk and thinking that its faster is equivilant to taking a sugar pill for a headache and thinking you feel better, or pressing a magic button on your shoes to make you jump higher. Its all in your head buddy...
