Originally Posted by Jonesin
I live up the street from there, (St. Laurent) and I just can't trust gas that cheap. Maybe I'm paranoid, but all I use is Sunoco's (Petro's now) Ultra 94.
Waste of money using anything but the required octane rating. In fact, it can be bad for your engine to do so.
Octane rating (in very general layman's terms) tells you how hard the fuel is to burn. The higher the rating, the harder it is to burn. Thus, using more than is specified for the car means you are using gas that doesn't burn as well, thus potentially leaving unburned fuel in the combustion chamber. It can lead to buildup of what is often referred to as crud.
They put a bunch of cleaners, et al, in higher end premium fuels, but you should be fine with 91.
And if you're worried about the Olco, ask them who supplies their gas. The cheap station near my cottage is supplied by Shell.