Well, I guess I am the guinea pig for this. I will be getting new pistons/rods when I go 12psi boost turbo, but until then, I guess I don't really care THAT much. I mean, yes engine maintenance is important, and I agree with the whole gas price to engine part replacement thing.
But since I'll be completely replacing the pistons/rods (which is where detonation would occur), I'm not that worried, especially after reading some articles on it (read further below). But since I've been driving since like... day 2 on 87 octane, I havent felt that much of a difference. I did switch to 91 for a couple tanks, and I can seriously say that 91 would have to strictly be for engine life.
But hey, maybe because I started on "sucky" fuel, my engine got used to it.
I looked at gas prices and realized that it's actually a much larger difference than I thought. It's a $.36 difference, so basically $4/tank. and I never get under 25mpg (hover between 25-27) I've had my car since june, and have 11k miles on it. Mostly with normal grade fuel. From my understanding, if you kept switching back and forth between premium and normal, that hurts the engine more than just sitting on normal grade all the time. And it makes sense too.
Here's an article I'm refering to
Basically timing will be retarded if knock is sensed, and engine will slowly push timing back to "normal" when octane changes. Well, if you keep switching back and forth, there will be more knock because it'll push it, and then all of a sudden you're back on crap fuel. If you stay on "crap" fuel, then your engine doesn't push the timings (as much) because the octane is the same, so the jumps in differences are all relatively the same.
So until I boost my SI, there's no need to put in premium. I'm not racing my stock SI, I use it as a DD. So the 5% loss in power is negligible. Sure I vtec sometimes, but as I said, I dont race (yet). I know what my car can/can not race.
So I guess my question is: Is my train of thought correct. I feel like my arguments are there, and can be inferred as correct, but I'd like some more opinions/ actual numbers. If you need any number off my car, I'd be happy to provide.