Question about octane requirements....

[corneileous]

Since the factory tunes on vehicles are preset to work with a specific octane fuel, does this hold the same for the other diablo tunes, NOT the performance tunes? I realize that, with the 91 performance tune for example, has to be used with the minimum of 91 octane. So on and so forth for the 89 Perf tune and the 93 Perf tune.

My question is, the modified stock tune, the mpg booster tune and the towing tune, is there a specific octane of fuel that should be used? I realize that in a previous topic I made that I was informed that a minimum of 87 would work in all three of those tunes. But what I'm concerned about is whether or not there is still a specific octane of fuel that works best since the factory tune on the Hemi for example prefers 89 and the performance tunes require at least what they're named.

Also, why does zero mileage and performance gains happen when you use higher octane fuel on the factory tune? And most importantly, why doesn't that seem to be the case with any of the diablo tunes? Does the factory set the PCM to work specifically on a certain fuel and you guys don't or what?

Thanks.

[corneileous]

Nobody? Wow.

[mikel]

octane has little effect on mileage.

The mod stock tune has no chnages and will work fine with the min octane required for the vehicle.
MPG booster and 87 tune are optimized for use with 87 octane or better fuel.

[corneileous]

The mod stock tune has no chnages and will work fine with the min octane required for the vehicle.
MPG booster and 87 tune are optimized for use with 87 octane or better fuel.

What all does the modified stock tune do, anyways?

So essentially you are saying there isn't a preferred grade fue recommendation for the mpg booster tune, correct?

[06MonteSS]

the modify stock tune doesn't change anything - it is just a copy of your stock factory tune that you can make your own changes to..

MPG Booster tune is for 87/89 octane...

[corneileous]

the modify stock tune doesn't change anything - it is just a copy of your stock factory tune that you can make your own changes to..

Hmm. I figured it was just only for those who didn't want to change anything engine-wise, but wanted to turn things off like the mds or something, or adjust for different tire sizes or gear changes.

MPG Booster tune is for 87/89 octane...

Thank you. I think I'll just stick with 89 since that's what my manual recommends.