This is based on US fuel. Fuel in Australia is of less quality than the most developed countries overseas. I have tested a number of fuels over the last 15 years. I race and have tested various fuels in my racer and in my various DD cars over the years. Of all the fuel available in Adelaide at the time i found that Vortex had the best economy, as much as 10% above some 91s. I tested by filling to the top of the neck and drving 200km. I did this over a number of months and each time Vortex came out in top. 98 was the best but economy wise it was pretty much on par with Vortex 95, only marginally better. The cars i tested this in were not tuned for 95 or 98. One was a Jeep that no one can even tune using the stock ECM. The fuel thing has been debated 100s of times across 100s of forums and few people end up agreeing. I trust my testing over some mob who is going out of their way to disprove something. The issue with Aust fuel over other countries is the filtering, we simply don't get clean enough fuel in our 91. My bro in law blows out yellow - brown sludge from choked up fuel filters from customers that think like most, that all fuel is the same..... He was the one that opened my eyes. He told me BP is the best but i used the fuel that i get the best economy and is cleaner than the cheaper alternatives. Talking to other members and friends over the years and people that give it some thought actually agree that Vortex comes out on top economy wise. One of these people was an old girlfriend who told me to make sure i put Caltex 95 in her car when i fill it as she got better economy. This came as a shock to me as she was not a car person at all. As for improving fuel economy you need to make some changes. Fitting a Mace CAI improved my economy as much as 2lph. I can get 9lph on the highway in my V6 if i fit the cover and that's not trying to conserve fuel. I could do better if i tried. I wouldn't get this type of economy using 91. But hey don't take my word for it. Do some proper testing, using 95 for 4 or 5 tanks, then do the same using a different brand. True testing takes a few months as you can't just dump in 50L of 95 and expect results.
I use E10 in my LS1 but it's been tuned for it, its making 266 rwkw on it with a baby cam. I think I may have gained another 3 to 4 kw on 98 after seeing a online dyno comparison of different fuels. E10 is guaranteed minimum 94 octane and 20 cents a litre cheaper at my servo. I plain on upgrading cam later I think I will do same again and run on E10. Here's the link to the comparison.
