holy_crap

I switched to 89 octane a few months ago and I can tell you that using the same driving I get and average 1.8 MPG more on the 89 octane. I ran 10 fills with each type and measured the MPG, not what the comp tells me. Here the price difference between 87 and 89 is about 15 cents per gallon, from 89 to 93 is about 9 or 10 cents per gallon depending where you go. I'm using 93 octane on this tank to see what I get, if it's significant improvement from the 89 I will run 9 more tankfuls to compare the 3 grades. BTW, on the 87 and 89 I used Shell gas. On the 93 I'm using Mobil (I get Upromise on Mobil)

tslewisz

If the Jeep will advance its ignition timing to take advantage of the added octane its possible that a little more MPG is possible. Some vehicles use their knock sensors to determine what tune to use and will take advantage of the octane. I've never heard that our Jeeps do this.

mr.brav90

are you also tuning your jeep computer to run on that octane level i believe thats whats made the diffrence for me i noticed 1 or 2 more gallons but i used a flash pack on the computer

tslewisz

That makes perfect sense.

ndenardo

I tried both octanes again on the same trip. 89 is defintly giving me close to two more mpg. I dont have a tuner to adjust any of the settings

birdiecat

Just returned from Key West and all along the I95 i ran 87 octane ,I set the cruise control at 75 to 80 mph and the computer says 20.4 mpg and did that from Daytona to Virgina and for full tanks of fuel and reset the computer a number of times. The jk is stock except for tires that are 265/70/18 ,

largo

I run the mid range 87 Octane and it seems fine to me. Not sure if super would change my MPG, but no worth the cost to me.

Tuto

Do you have a SuperChip or other type of programmer?

SuperChip has different tunnings for each Octane grade. Performance 87,91,93. (adjust Timing)

MiliageX -My gas Mileage 125 miles X 2= 250 miles (80 Highway -20% city) got 19.5 mpg(87 Octane) using the MileageX -Driving at the posted Speed limits. Using 87 Octane. Before it was 17.4 MPG.
I also notice it at the pump !! Every little helps but only time will tell.

dadgummit

LOL you are correct. I always think it is funny when people think higher octane means more power. Octane just raises the temperature the gas explodes. Nothing else. In higher compression engines if you use gas with too low octane it can explode too soon (From the heat of compression) so you need higher octane. If you put high octane in a vehicle that does not need it you are just throwing money away.

ndenardo

Say what you want, but after many tests it proves to give an extra 1.5 per gallon every single time. As it has for many others.