lol i only tested the fuel at differnt levels in my truck becuse i was driving 5 hours one way and i had nothing else to do! LOL and with my van i was curious becuse i ran 89 and it was good so i tryed 93 and it didnt change? my sundance my mom put a full tank of 87 in it! well it lasted 2 days of driving.. and was spark knocking alot while driving.:bang headIt is worth testing your fuel economy at each level, but with the 4 and 6 cylinder cars I have had, I have found premium fuel made a huge difference with regard to fuel economy, while the V8s showed no real difference. If you're just cruising around and not getting on it all of the time, the lower octane is probably fine, but run a tank or two of each and record the results to determine if it is worth spending a little more per tank at the pump. For me, it has paid off.
You aren't likely to do either, really. Depending upon where you drive, you will have higher or lower octane for premium anyway, so if you were to drive across the country, you may come to a point where premium is 90 octane. If you're driving the car hard, the higher octane will help performance, but if you're just cruising, you may find the lower to work.So still kinda up in the air, again like I said not much racing around town, just cruising and what not, and mileage still sux!
But worried about knocking and blowing it up if I run less than 92-93!!!