Originally Posted By: Patman
In an effort to save money, I've just switched to Pioneer 91, since it's a little more than 4 cents/liter less than Petro Canada's 91. The only thing with Pioneer is that you never know who the supplier is, they change suppliers every month depending on who gives them the best price. So one month you could be getting Esso's 91, the next month it could be Shell. In the old days when Sunoco was their sole supplier, they offered "Magnum 93" and it was actually Sunoco's 94 octane!
When I make a circuit of all the brands in my engine (BMW M52), I always end up coming back to Esso 91 E10 (92 in the past) for summer and Shell V-Power 91 E0 in the winter as having the best performance *AND* fuel economy. I don't like to sacrifice either (or both, as is the case with some brands).
I never found Sunoco 94 to be particularly high performance except for about 4 tanks purchased between 2000 and 2005 which were truly special. It has a high AKI which either you need or you don't. Those 4 special tanks were really special. The Porsche I had at the time called for 93 and immediately after fill up the idle was smoother, power was up 20% according to the butt dyno (I was quite in tune with it's typical performance and there was a few cases where going WOT had an element of fear in it on these tanks) and the fuel economy went through the roof. It was all undone as of the next Sunoco 94 fill up, even if at the same station but weeks later.