Ok so I have question if your running a FI setup could you run it on 87 or 89 with water-methanol injection instead of 91 or 93? I would figure that it Would give you a funny octane but it would work in my mind.

 

I'm sure you could but not sure why you would. Unless you're running high boost which would require high octane and methanol. So theoretically it would work but probably not worth the trouble of just using a higher octane.

 

Not high boost not any higher than 10 psi for now but when your paying 4.50 for 91 I'm just trying to figure out the most bang for my buck

 

Yeah but you're looking at purchasing a water or meth kit and trying to get the tune correct. Not to mention buying the meth if you choose to go that route. $6k easy for a blower kit and you're concerned about gas prices? C'mon man just bite the bullet at the pump for $5 more on a fill up. Although a good custom tune may allow you to run 89 octane on a safe tune I really wouldn't worry about gas prices on a charged mustang. Meth injection may still be a good option but I would still be running 91 octane with it.

 

Very good point I was trying to figure out the math but it just didn't seem right Iv got the power itch but I only have 6k miles on her and the warranty Wont be up for another 93k or 4.6 years and I don't think I can wait that long