So, is the increased fuel economy that you're experiencing worth the increase of price of Premium vs Regular? In other words, are you saving money by doing this?
it's hard to tell...i would realistically need a scientific example to determine the real improvement (assuming there is one), but our routines are fairly consistent, as has been the fuel economy over the last few years, so seeing numbers in the mid 10s is a new thing...assuming a 2L/100km improvement, and a 65L fuel tank (?), that means i can go about 100 kms more on a tank of fuel...assuming fuel economy numbers of 10.5 with premium and 12.5 with regular, over a 65L tank, that would give the following numbers:
Regular (price made up for example):
$1.20/L x 65L = $78 tank of gas
65L / 12.5 FE = 520 km total range
Cost per km = $0.15 per km
Premium
$1.32/L x 65L = $85.80
65L / 10.5 FE = 619 km total range
Cost per km = $0.1386 per km
let me know if my math is wrong (it may be), and keeping in mind, this still isn't a scientific experiment, but as i suspected, the cost difference (assuming you do get improved fuel economy) is likely negligible...in this example, it's actually cheaper to use premium, but i don't want to say this is actually true in case it isn't...my guess is, even if it isn't 100% accurate (it won't be), maybe i break even or the extra cost is minor enough to just use the best gas possible.