[Tyler-98-W68]

4.25 years is... old... :laugh::wink:
Well 87 octane near 5000' is like running 89 at sea level. No alcohol is even better.

My 2014 has had 87 from day 1 as has my 2016, I've felt like lightening my wallet a few times and tried 91 and 94 octane and its really funny NOTHING was different except I was out a few extra bucks

 

[Bellingham Trailhawk]

My 2014 has had 87 from day 1 as has my 2016, I've felt like lightening my wallet a few times and tried 91 and 94 octane and its really funny NOTHING was different except I was out a few extra bucks

Well by 2018 at least the owners manual changed to say 87 is recommended and that using higher octane fuel provides no benefit, instead they recommend using Top Tier gas. So I only use 87 but I also only use shell, however shell accepts works Fuel rewards so i get a discount on it.

 

[sadatoni]

87. No pinging.

 

[roadrunner_clams]

I have used 87 since the car was new in January 2015 . I have a little over 60,000 miles on it now and just did a highway trip from the New York area south to Atlantic City and it showed 34.7 mpg on the trip computer.

 

[Good1Brian]

87 octane on V6

 

[Mark_]

I have used 87 since the car was new in January 2015 . I have a little over 60,000 miles on it now and just did a highway trip from the New York area south to Atlantic City and it showed 34.7 mpg on the trip computer.

Which day was this ? I'm looking at weather data to see just how good a tailwind you had there :wink:
Past few days I see winds from the North and NNE in the NYC area, which would definitely have helped produce that number heading to Atlantic City.

 

[RandyC]

89 Octane

I started using 89 octane a few years ago after monitoring my gas mileage against using 87 octane. I found a 14% increase in fuel efficiency. Even though the 89 octane was more expensive, the increase in price was less than the 14% increase in fuel mileage.

 

[brent]

Wow at 30 mpg a 14% increase is 34mpg. That's amazing!!!

 

[Jeepster1]

I started using 89 octane a few years ago after monitoring my gas mileage against using 87 octane. I found a 14% increase in fuel efficiency. Even though the 89 octane was more expensive, the increase in price was less than the 14% increase in fuel mileage.

Octane has nothing to do with mpg sad to say. It has everything to do with combustion ratio and fuel burn needed that is required by a particular engine. Using a lower than required octane will result in engine pinging which from what I understand is fuel combustion outside the normal combustion cycle in a cylinder. Not good for the engine.

Many different factors go into mpg increases and decreases including time of year. Using non ethanol gas or 100% gas typically will add at least +2 mpg. That is a direct easy factor. It does not change.

If your gas companies use ethanol blend and are not required to post % in the gas then that could be another factor.
A station I deal with has 87 10% and 92 premium no ethanol gas. If I used that gas my mpg would spike at least +2mpg. But that would be because of the no ethanol in the gas only. Not the octane.

Obviously you picked out a gas that is delivering you better mpg but I suspect its another factor you stumbled upon. With your calculations you found a sweet spot on cost vs mpg.

My sweet spot is a .25 cent(US) per gallon difference. When I find 87 octane 100% gas at that or lower its worth buying as my mpg does go up enough. But here in Illinois the pump for each grade has to be marked, though sometimes not clearly.

 

[fusseli]

Non ethanol gas or 100% gas has 2-3% higher energy than E10, thus you can expect a max. of 3% increased mpg which is 0.6 mpg max at a 20 average. They have this in the pumps around here for farm equipment but it's usually almost a dollar, or 30%, more than regular 87. Not worth it in the slightest.

I've tried using 89 and 91 on highway trips and haven't noticed anything. Terrain, speed, and windage are much greater effects on mpg... making it very difficult to measure a tiny improvement

 

[Venum29]

I was looking at the Owners app Jeep. It says on the PDF of the owners manual Fuel selection for 2.4L and 3.2L Engines 87 Octane, 0-15% Ethanol. I have a 2017 3.2L v6 4x4 Latitude, so... I have always used 87 Octane.

 

[JeffD]

2016 V-6, 87 Octane for 18K miles and a couple thousand towing and no issues or ping.

 

[Tyler-98-W68]

2014 3.2 87 Octane. Able to command the maximum timing tables in the PCM = higher octane would do nothing.

 

[sanghill]

Does 89 octane do anything useful to the valve timing? I was hoping valve operation would provide more torque.
I have factory tow, does that benefit from 89 octane.
I usually run cheap 89 octane locally and 87 octane on trips when I can't get inexpensive gas.
When I go off road in 4 low and pulling steep hills I like 89 octane and hope that maybe it helps.
Never had a problem with 87 octane and 89 octane makes no noticeable difference.
Maybe your scan tool can detect something?

 

[Tyler-98-W68]

Octane does nothing other than prevent knocking, its not for fuel economy its strictly to reduce engine knock. As i've shown my 2014 can run maximum timing and get max performance using 87 octane, a higher octane would do nothing.

You also aren't got WOT in 4-low very often so higher octane again would do nothing for performance. I run data logging software and what i've posted above explains it all. 87 Octane allows maximum performance on the 3.2 V6

 

[sanghill]

That is GREAT news, you just saved me a lot of money!

 

[RichBrew]

2014 3.2 87 Octane. Able to command the maximum timing tables in the PCM = higher octane would do nothing.

Is there any of this info around for newer models? I'd be curious if it is still the same for 2019+

 

[Tyler-98-W68]

Is there any of this info around for newer models? I'd be curious if it is still the same for 2019+

The 3.2 Pentastar has not changed, so nothing would have changed. I don't have access to a Turbo cherokee so I cant log with HP Tuners to find out

 

[RichBrew]

The 3.2 Pentastar has not changed, so nothing would have changed. I don't have access to a Turbo cherokee so I cant log with HP Tuners to find out

Thats what i was thinking, thanks for confirming.