Ive been running the 87 tune but from what Ive read on here the 91 is the way to go. Problem is that maybe one gas station around here offers 91. I just switched to the 93 tune with 93 octane. Can I run the 91 tune on 89 octane or 91 tune on 93 octane for better performance?

 

My suggestion - fill up half with 87 and half with 93 (or slightly more 93). If you notice, prices are usually not fair for midgrades (is not priced linearly by octane). Stations only have two tanks and pump mixes for mid-grade anyway. Its a ripoff, basically. I always "self mix" for midgrade to save money but as much as a matter of principle!

 

you can run 91 tune with 93 octane runs fine.

I wouldn't run 91 tune with lower octane it'll run rough after a couple of tanks.

I was using 87 tune (87 octane) but after comparing costs I changed to 91 tune. Most stations here are 93 octane but no issues with 91 tune. My cost/mile is cheaper using the higher octane.

 

Hmm thanks for posting this. I think I might switch. So is it best to use 91? With the 91 tune?

 

I am new to the superchips flashpaq because all previous jeeps had standard transmission. I just recently bought a 2007 with auto transmission and i immediately bought a flashpaq. I have the same problem in my area. We have either 89 or 93. I went ahead and did the 91 tune but used 89 octane gas. Only half a tank just in case the engine started pinging on heavy acceleration. On my first test driver she took of like a bat out h*ll with no issue. Drove her two weeks that way with no noticeable issues. I just recently decided to start buying 93 octane and do not really notice much of a difference. Very glad i bought the flashpaq. Obviously my results mean nothing. Just what i have observed.

 

So would it be best to use the 91 or 93 tune with the 93 octane?

 

I would assume 93 with 93?

 

i was running 87 and flashed with 87 tunning. I was getting 16.7 MPG. I switched back to stock to get my oil changed. When I flashed it after the oil change, i used XS (fuel saver) with 87oct and am only getting 15.2 MPG now. I need to fill up tomorrow or saturday, I am thinking of trying 91oct. What should I expect with that octane and that tunning mode?

 

We have the same problem in Texas. I tried 89 octane on the 91 tune, and there was a small amount of knocking. I did what JKPier did - filling up with half 93 and half 89 octane. Works great with no knocking.

 

While I haven't tried the XS tune (I run the 87) I have read in other threads on here that it's anything but a fuel saver. I believe the consensus is that the XS tune is junk. I have only had the 87 tune for a few hundred miles (I don't drive the Jeep daily) and have to say it's a huge improvement over stock. I may try the 93 next with 93 fuel. I'm in Maryland and our stations generally have all 3 grades of gas.