What octane do you run?
- Thread starter Ant's JK
- Start date
SteelBadger
New member
I was just going to ask the same thing. I normally run 87. Last fill from 3/4 empty I used 89. I am not sure but my mileage seems a tiny bit better. Could just be coincidence but I am going to run a few more tanks to see. Not sure it is enough of an improvement to offset the cost either.
MountainRambler
New member
I run 87 which is the cheapest in my neck of the woods, high octane ratings are not necessary except for high performance engines found in fancy sports cars. If I can find it I buy ethanol free gas, gives you better mileage and is easier on your motor.
SteelBadger
New member
I get the whole compression/ignition thing with higher octane, but just wanted to try it. Maybe I am just wasting money. The manual says 87 I believe. Guess I should stick to it.
JeepFan
Hooked
Basically if your engine is not experiencing pre-ignition (pinging) running 87, then you might be wasting money. I occasionally run 89 when the price drops because my Jeep gets slightly better mileage and seems to perform slightly better.
SteelBadger
New member
I thought so as well but didn't want to say for sure until I ran a few tanks for a larger data sample.
redpatchjeff
New member
I run 87 octane with no problems. I will say that the flashpaq did improve my mileage and performance and if I jump to the 91 tune I will run 91 or 93 octane.
^^^This.
If you are running a stock tuned engine there is no advantage to running higher octanes. There are some better/different cleaning agents in the premium fuels so I sometimes will fill up with premium for that purpose but not for performance gains.
I will also fill up with higher octane fuels when I know the Jeep will be sitting for awhile. Today's fuels all contain ethanol which looses octane over time. If it takes you over a month to get through a tank you might consider bumping octane so you still have 87ish by the tanks end.
The reality is that once the engine is warm and the control loop is closed, the O2 sensors are being monitored and the injector pulse width is being altered in a manner that the octane difference is negated. I think those seeing "slight" improvements are having a placebo effect but I could be wrong...
Jeeper Jr.
New member
I'd guess a Placebo as well. Octane has more to do with how resistant the fuel is to detonation, not its power content. Running a higher octane will not help you make power.
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JeepFan
Hooked
Maybe a Placebo but running 89 could trigger the computer to run slightly more advance in the timing which would translate into better performance and fuel mileage. Just my :twocents: Of course, your mileage may vary!
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jeeeep
Hooked
2010 JKU auto, Scream'n Demon coil and wires, stock plugs gapped wider.
I have mine tuned to run higher octane, I see better response and mileage if I drive normal.
When I change the tune to run 87 it's less responsive but mileage is about the same.
When I can find ethanol free gas I get the best response and mileage with either tune - better mileage with the premium tune.
Ethanol is a mileage killer and wish they would do away with it, it's getting harder to find ethanol free stations
unless you're tuned to run premium, you're better off running an octane boost every couple of tanks in humid climates -ethanol attracts water..
I have mine tuned to run higher octane, I see better response and mileage if I drive normal.
When I change the tune to run 87 it's less responsive but mileage is about the same.
When I can find ethanol free gas I get the best response and mileage with either tune - better mileage with the premium tune.
Ethanol is a mileage killer and wish they would do away with it, it's getting harder to find ethanol free stations
unless you're tuned to run premium, you're better off running an octane boost every couple of tanks in humid climates -ethanol attracts water..
SteelBadger
New member
I can't deny that. That is why I would have to evaluate it with a longer trial while keeping track of highway/city driving etc.
Not entirerly sure it would be worth the effort:bored01:
