Which tune for best mileage?

[lilgio68]

I just installed the diablo tune but will be driving about 190 miles today so want the tune that will save me the most gas. I have 91 octane gas in my car right now but which tune will be best for mileage? And will it take the car 50-75 miles to get used to the changes or will it start saving right away?

I have a 2005 gmc Yukon predatorU7193

[06MonteSS]

doesn't really matter... getting your fueling dialed in via the injector slope setting so that your average ltft's are in the 0 to -2 range is what's going to get you the best mileage...

but even with out doing that, you should get some better mileage with either one of those tunes.. 1-2 mpg....

[jcbst12]

Look at it this way, if you keep your foot out of it and gain 1/4 a MPG on average with 93 octane over 87 then you are saving roughly 6.5 gallons of gas each tank (with a 26g tank) which translates to roughly $19.5 a tank (for the 93 stuff). All the while this had cost you an extra $9 a tank which translates into 3 more gallons of fuel....not to mention the added fun factor. Now 91, I assume will get you less which if worst comes to worst you would break even I would think.