I searched a bit and saw threads comparing 87 octane to 89 and others, but not 85. Here is Utah, basic unleaded in 85 octane but the manual says to run 87. Most pumps are 85-89-91. Does anyone have any thoughts on running 85? I am not looking for better fuel economy, just looking for what is best for the engine. There is one chain that I am aware of that sells 87 (Maverick), but they are not everywhere.

 

personally I would go with 89 over 85. Or if you want to get fancy fill the tank partially with 85 and partially with 89.

 

Do you notice any ticking or knocking with the 85 octane? If not, you may be okay.

 

The reason they sell lower octane is because you're buying gas at higher altitude. That means lower octane is needed to prevent pinging. If you don't have pinging in your JK when driving it under duress (low rev's headed up hill, for example), then stick with the 85. My experience after a few days in Moab last summer was that 85 wouldn't cut it. My son and I felt the reduced horsepower, there was pinging under duress, and the gas mileage, which we diligently tracked for 5K miles of driving that trip, suffered miserably (well, part of that may have been because we were wheeling some!). Having said that, let me also say that from three different gas stations, using mid, then premium grades, we still suffered all those symptoms. I don't trust the stations in Moab.

mark d.

 

why not use premium??
does it realy matter that your(wasting)$4.00 or something more a tank
gas stations should have 2 fuels 1 prem unleaded and 2 diesel done no choice no problem

 

If I'm not mistaken, Higher octane fuel is slower burning. Because of this, sometimes using a higher octane fuel actually can cause damage to the emission system over time (I.E. clogging the catalytic converter, etc.) which can end up resulting in reduced performance with time.

There are no benefits to using higher than needed octane. There's no power increase. There's no increase in fuel economy. You're paying for nothing. Save your money for jeep accessories

 

your prob right
but i never used anything other than prem in anything that took gas
and i never had a fuel issue in anything
mabey its all in my head mabey not

 

x2
My dad sold gasoline for most of his adult life, and this was one of the first tips he shared with me.

 

yep my old acura required at least 91 octane.. i always ran prem in it..

The Jk tho, never anything over 87..

I never heard of 85...

 

When I lived in Montana the pumps were set up this way. I always ran 85. Because of the lower levels of oxygen at altitude you are supposed to run a lower octane fuel. As far as power goes I think I have heard that you will lose 10% of your engine power for every 1000 feet above sea level you go, so there aren't really any power advantages to using a higher octane fuel.