Quote:
Originally Posted by Groovy Chick
 Don't do it... 
The answer is that TECHNICALLY you can run 93 octane with an 87 calibration. However, you run the risk of detonation even with retarding the timing. Also, your 87 calibration was written with a particular timing curve. By backing off the timing of a 93 octane program, you are affecting the whole timing curve and will be sacrificing fuel economy.
Ask yourself, "Self, is it worth it? Am I feelin' lucky?" 
Yay! I knew the answer!  |
Corey,
respectfully, I'm not sure you're right on this and I think we need an opinion from the Mad Doctor.
I believe you can ALWAYS run higher octane fuel in a low octane fueled vehicle. (OK to run 93 octane in an 87 octane tuned truck). And, since the octane is higher, you should be able to bump the timing a bit to at least recover most of what you would lose by using the higher octane fuel in a lower octane tuned vehicle.
The reverse is probably not true. I wouldn't try to stick 87 octane into a 93 octane tuned vehicle, because, as you say, you still run the risk of detonation under certain conditions (unless you backed the timing WAY off).
But, he won't get the full benefit from using high octane fuel unless he has a custom high octane tune - we agree on that - 100%.
- Jack