Originally Posted by Colorado700R
What elevation are you at? It may have an effect on your octane requirements. I.E Higher elevation requires less octane.
I live in ND, so the highest I would probably see would be no where over 3500 - and that's pushing it.
Edit: Just did a google search, our highest point is 3,506 to which a part of the state I don't travel! So I'd say around 2,200'ish.
Originally Posted by snrusnak
The 87 tune is still a good performance gain over stock.
You MIGHT be able to get away with the 89 octane on the 91 tune. If your truck is lighter, say 2wd, reg cab, short bed, you could probably get away with it.
It is a quad cab 4x4 short bed, so I doubt I would. Suppose I can just play with the 91 with the short time I'm off, then switch it back to stock with the MDS off to get my moneys worth.