Can this cause me problems? We only have 87,89, and 93 here at the pumps. I have been running the 87 tune, but I always put 89 in the tank so I thought I'd change to the 91 tune. It seems to run better, but will it hurt my jeep to run it this way?
Is it to lean? I live at sea level and I have a CAI and Exhaust.

 

You shouldn't run any tune at a lower octane. If you are worried about gas costs, run the 87 tune.

 

When you put a load in the Engine. You will get engine Pin/Noise. And if not careful and keep giving it gas you can cause damage to the engine.

 

Try running tow mode on 87... great notiable power. try it, you'll like it.

 

I run the 91 tune with 93 octane. I love the increase in power and mpg's over stock.
Realistically at the current prices the difference in a fill up of 87 and 93 is less than 5.00. For me its worth it. Just my thoughts.

 

X2. People cringe at the price per gallon difference, but realistically it is not much.
I run the 91 tune and always put in the 91 octane.

 

For those of you running the 91 tune, what kind of mpg's did you gain over the 87?
Agreed on the actual cost not being THAT much more in the end so I'm thinking of trying 91 on the next fill-up and changing the tune to go with it.
I'm guessing it would take a couple tanks worth to notice any real difference though while the computer re-adusts itself?

 

You'll risk getting a ping, or pre-ignition, which is bad for the ol' engine. I wouldn't run a higher tune than the octane. If you want to run the 91 tune, I'd go with the 93 octane. That should help run the engine a few degrees cooler as well - a nice side-benefit.


Same here. I definitely noticed a difference between the 87 tune and the 91, and so now run it (the 91) all the time now. Works even better with the SprintBooster!

 

Not much in the MPG's that I noticed, but I did notice a better sense of power when driving. However, I did need to run at least an entire tank of 91 before it "learned" the new tune. But that second tank seemed much better.

 

My mileage went WAY down with the performance 91 tune. Might have just been me getting used to it but I lost mpgs.