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What fuel octane do you use?

I've always put Shell 93 octane in mine, wondering if I switch to 87 would MPG be any better since the manual recommends it. What octane do you run and what’s your MPG?
 

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I've always put Shell 93 octane in mine, wondering if I switch to 87 would MPG be any better since the manual recommends it. What octane do you run and what’s your MPG?
These are the threads we already have on octane. Should find your answer in them. If you use the search feature in the future you can get your answer faster. Everything about the Commander has been asked and answered on the Forum.
By the way if you have a HEMI use 89 octane ( or 87) just like the manual recommends. Using anything higher actually gets you poorer mpg and can cause other problems.

http://www.jeepcommander.com/forums/showthread.php?t=11494&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=3373&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=6860&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=1782&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=932&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=765&highlight=octane

.
 

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I'm running 91 in my Hemi but I have it tuned with the flashpaq.

I haven't been very impressed with the gas mileage so I'm going to retune it and start running 89 again to see if that helps. Depending on how that goes I may even try 87 again....

Only reason I bumped it up to 91 is really to get a more consistent octane. I'm not sure if its true or not but I've heard the intermediate octanes at the gas stations are just a mixture of 87 and 91. Could be a complete rumor but I haven't found a direct answer...

I'm getting 12.5 MPG around town now.. and that's after a fresh plug change. I do have the 2" RC and 245/70/17s so that doesn't exactly help my mileage..... but it seems like I'm getting worse than others claim they're getting with similar or more aggressive setups, and I don't exactly drive like a bat outta hell with my 1 year old in there either.
 

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If you use the search feature in the future you can get your answer faster. Everything about the Commander has been asked and answered on the Forum.
.
While that's true.... this site also seems to have a very low daily post count. I've been around forums a long time and now my commander is my primary vehicle.... I'm trying to make this forum my main area of interest but its very difficult with a lack of new threads/discussions.

In the interest of growing the popularity and freshness of the site, it may be a good idea to welcome new members and their posts as opposed to the typical "don't post any new threads, do research and find your answer so we never hear from you" type message that I've been seeing on a consistent basis.

$0.02
 

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I've had an interesting experience lately...

Last week I had half a tank of 87 octane and went to fill up before a trip. At the gas station I guess they were having trouble with their pumps, but the guy could only sell me premium 91 octane (for the price of regular). It thought, OK, that will mix out half-and-half to give me around 89 octane for my Hemi. Now, I've been running regular for quite some time without any issues. So driving around that day I got the impression that the engine was running a bit smoother. Mileage was unchanged. This is very subjective, but it just seemed like the Hemi preferred a little more kick. BTW, I'm also running iridium plugs, if that makes any difference.

BTW, Matt, what's your mileage, when did you last change your plugs, and what kind are in there now?


:eek:rangehat:
 

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Discussion Starter #7
These are the threads we already have on octane. Should find your answer in them. If you use the search feature in the future you can get your answer faster. Everything about the Commander has been asked and answered on the Forum.
By the way if you have a HEMI use 89 octane ( or 87) just like the manual recommends. Using anything higher actually gets you poorer mpg and can cause other problems.

http://www.jeepcommander.com/forums/showthread.php?t=11494&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=3373&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=6860&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=1782&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=932&highlight=octane

http://www.jeepcommander.com/forums/showthread.php?t=765&highlight=octane

.
Okay thanks will search next time around

I'm running 91 in my Hemi but I have it tuned with the flashpaq.

I haven't been very impressed with the gas mileage so I'm going to retune it and start running 89 again to see if that helps. Depending on how that goes I may even try 87 again....

Only reason I bumped it up to 91 is really to get a more consistent octane. I'm not sure if its true or not but I've heard the intermediate octanes at the gas stations are just a mixture of 87 and 91. Could be a complete rumor but I haven't found a direct answer...

I'm getting 12.5 MPG around town now.. and that's after a fresh plug change. I do have the 2" RC and 245/70/17s so that doesn't exactly help my mileage..... but it seems like I'm getting worse than others claim they're getting with similar or more aggressive setups, and I don't exactly drive like a bat outta hell with my 1 year old in there either.

While that's true.... this site also seems to have a very low daily post count. I've been around forums a long time and now my commander is my primary vehicle.... I'm trying to make this forum my main area of interest but its very difficult with a lack of new threads/discussions.

In the interest of growing the popularity and freshness of the site, it may be a good idea to welcome new members and their posts as opposed to the typical "don't post any new threads, do research and find your answer so we never hear from you" type message that I've been seeing on a consistent basis.

$0.02
Thanks for the feedback Matt and the indirect warm welcome!
 

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When I first got my Commander I ran 89 but when gas went up considerably, I switched to 87. I didn't try to compute the change in mpg's if any.
 

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I have the Superchips flashpaq with the 91 performance tune installed so use either 91 or 93 octane (whichever the gas station has that I go to). However with gas prices soaring, I might switch back to the 87 performance tune and use 87 again and see what happens. I didnt really notice that much of a difference in gas mileage, however my mileage has always sucked. Just more power with the 91+ octane on the performance tune.
 

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Book calls for 87 for my 4.7, but I have used Amoco Silver 89 since day one. I have had zero issues with my engine - now about 46K. The only $ spent on my engine was plugs @ 30K. :eek:rangehat:
 

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I run 87 on my 4.7 V8. It runs smooth and power is adequate. I tried running higher octane fuels, but really couldn't feel a difference. I tow with mine and still couldn't feel a difference with a higher octane fuel.
 
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