don't have a mini but seriously thinking about getting one as my next car. What octane rating does the mini use? Im guessing the S uses premium but not sure about thebase mini.

 

All modern Mini's use premium gas. Once I absent mindedly filled my base Mini with regular (All my other cars use regular, and I just spaced out on what I was doing until the tank was full), and the effect was immediate and obvious. The engine was noticably less powerful & the mileage went down the drain. I added octane booster and it didn't seem to make it run much better. I just ran the tank mostly out and went back to premium. Even at that it seemed to run lousey for another tank full or so. I have been told that the Mini can sense detonation that occurs when you run regular, and automatically retards the timing to prevent it. That is just what it felt like it did. I am not sure how it knows to advance itself again, but it eventually did.

I had a guy tell me that the intermediate grade works OK in his base Mini, but I am not even going to try it.