I'm sure this may have been discussed before (more so on the hybrid forums) but I just wanted to get some opinions on they type of fuel people were using. Recently my wife bought a 2010 golf gti and i was just putting regular gas in it until she told me that it didn't seem to drive as quick as it used to when she first got it. I did some research and other owners had echoed the same thing when they switched from premium to regular.
I was always under the impression that the premium gas was for older high performance cars that might not have a knock sensor and couldn't adjust for the early combustion so there was a retardant of some sort added to the fuel.
Anyway, I check the gti manual and it specifies at least 91 octane. The pilot gas station that I was getting all my fuel at because they let me park my truck there has 91. I have noticed a few other gas stations have 93. I have started fueling at Racetrac because I get points for fuel purchases (unlike Pilot rewards which doesn't recognize fuel purchases).
Getting back on track, when I had a rented Chevrolet Volt, the owner told me it only takes premium gas. I then looked around the forums and some C-max hybrid owners claim they are getting better gas mileage when using premium fuel. At current prices, I don't mind putting premium fuel in the car if it means I have to fill up less often.
Now I see that there's a blue pump at racetrac with has ethanol free fuel. I asked someone at the gas station about it and they said it was for boats and smaller engines that don't have the same filtration as cars do. However, I see some people will only use "pure" fuel in their cars.
Then there's the mid grade or 89 octane. If I am to go by the fingermarks on the pump buttons, NOBODY uses mid grade.