Ok so my Superchips is on the way. I am running a stock 07 unlimited. The question that I have is, is will I see a bigger performance gain and/or mpg increase by running the 93 octane mode instead of the 87? Or would it only be beneficial to run 93 mode once I install an exhaust and intake because of the chance of engine knock from the added air into the fuel mixture?

 

are you planning on running 93 octane gas? If yes run the 93 tune. If no then don't run it.

 

My findings were that I experienced the best performance gains with the tow tune, the best efficiency with the 93 tune (although cost/value led to the determination that fuel prices needed to be above $3 a gallon for it to be cost effective) and I am currently running the 91 tune. I don't have very solid numbers yet as the weather has been changing, but I suspect that the 91 tune is going to offer nearly all of the efficiencies of the 93 tune and power that I wouldn't be able to differentiate in a blind test.

One thing I can offer is with both of us living in similar climates, don't waste the cash on higher octane fuels in the winter. Run the 87 tune Halloween to Easter so you aren't wasting more expensive fuel while your vehicle takes longer to get up to operating temperature. Until you reach operating temperature you are running in open loop, which means a pretty rich A/F ratio. This is where the myths about winter gas come from, and it's really just that it takes the engine longer to warm up.

 

I would only run 93 octane gas if their are benefits from it, IE. better fuel economy or better performance, otherwise I am just going to run 87 octane. May have no other choice to run a higher octane gas after i put on exhaust and intake?

JPop, thanks for the info, especially about the winter fuel. Seems like you know a thing or two about the superchips from what I have read in other threads. Looks like I may just run a couple tanks of each octane and see how it goes. Can you run the tow tune with any of the octane gases?

 

Tow tune is for 91+ octane.

Also, keep in mind that you need to get some time logged with each tune. A tankful at minimum, or 40 normal driving cycle key on/off cycles. I have charted efficiency improvements through 3 tankfuls before the PCM is really dialed in, but after the first tank it's not going to be perceivable.