gas in South Dakota

[bommer]

Hi -

Just got a predator for my 2006 Dodge Durango with 5.7 Hemi.
My truck manual says 89 octane recommended, 87 ok, but not to run 91.

I understand that my truck engine is lower compression hemi, doesn't need the 91 octane.

We have three main gasolines here.
1. 87 octane
2. 89 octane with 10% ethanol
3. 91 octane premium which is 40 cents/gallon more

The predator has tunes for 87 octane, 91, and 93.

My question is why there isn't a tune for 89 octane with 10% ethanol. Runnng the premium 91 is going to cost me $10 more every tank of gas.

Thanks for anyones enlighenment in advance.

Paul

PS- does the performance tunes shut off the MDS or do I need to do that as a modify?

[bommer]

I found on the predator U7136 they have 89 octane tunes,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,for 300, magnum ect

U7136 Stock Vehicle Tunes:

93 Octane Performance Tune: Designed to add maximum power and torque using premium 93 octane fuel
91 Octane Performance Tune: Designed to add maximum power and torque using premium 91 octane fuel
89 Octane Performance Tune: Designed to add maximum power and torque using 89 octane fuel

[HESCO]

the tunes are basically the difference in the timing added over stock. the higher octane fuel you run the more timing you can run without it pinging....more timing= more power