I'm considering buying all my fuel from CostCo. (I don't have the membership yet, but I've been looking at one anyway.) 87 petrol is typically 10c cheaper around the 100c mark, and 91 would be closer to 12c cheaper. That's about 5$ off per fill, and I fill up about once a week. That would pay for the membership several times over ...

The ethanol argument does make me wonder, though. Seriously, Shell's the only one? How have the other companies not considered this?!

 

I was in my Air and Fuels class today and coincidentally they were talking about Ethanol and Methanol. The teacher I spoke with told me that there should be no significant difference in using ethanol gas since ethonal burns cleaner and has a higher octane rating then gasoline (110, if i remember correctly).

Im trying the Shell gas for the millage right now because i used to use Esso. I got 330-340 a tank on Esso, but i will post the results later. So far, since im running a midpipe, I noticed that shell gas doesnt stink like crap like the Esso gas.

 

If you're referring to gas mileage, energy density will play a major role. In this regard, Ethanol is significantly worse than gasoline. Overall effect on mileage shouldn't be more than 2-3% for a 10% blend, but a measurable difference is to be expected.

 

I've been using Costco Premium Gas, and supposedly they get there gas from Shell. I was an avid V-Power user, but from what i've seen i get around the same mileage on both 380-400kms/tank both hwy/city driving.

I can't believe when i saw Shell's v-power hitting 1.21/liter, where Costco gets me 1.09/liter. Helps the students pocket for sure!

The only thing i do not know is if Costco does buy from Shell, is their 91 a non-branded V-power gas? I would assume so, no?