Just to add to anecdotal evidence of one kind or another:
I have a M6/LS3 and I did the fuse thing a few weeks ago. The car definitely ran smoother, was more responsive, and even seemed to shift easier (though I still don't know if that was my imagination or not).
After a week of that, everything reverted to pre-fuse-pull days. I wondered if a recent fill-up (Exxon 93 octane) did it. Maybe I got some bad gasoline. Another fill-up, no change.
Last Saturday I filled up again, at the same gas station with the same octane. Within a day, all the smoothness and pep was back again, without the fuse trick. Yesterday I
accidentally spun my tires, pulling out of the driveway at work, with competition mode on.
Based on the above, I'm thinking:
- The Camaro defaults to the high-octane tune table.
- There's more to it, within the ECM, then just the tune table.
- The car is extraordinarily sensitive to octane.
The car really shouldn't be
that sensitive to the octane, IMO, or at least not make the driving experience so very different when switching octane levels.
That's my current theory, which is probably, in reality, as wrong as possible. But it explains my observations, at any rate.