Originally Posted by Fuzzy Logic
i really didn't think 87 => 89 would make that much of a difference, but for only $0.10 more a gallon... i thought why not try it at least once to see?
i've been lucky to have a non-finicky dct which just got smoother as i put more miles on it, but switching to 89... i was looking at my tach and saw the rpm's changing when my car shifted... but this time, i couldn't feel it shift. now with the miles i put on it, it already shifted smooth; but if you paid attention you could feel the shifts.
89 in the tank, i just couldn't feel the shift / made the vehicle that much smoother. i'm impressed. as long as gas keeps falling in price, i'll go with 89 for the time being. using 87 wasn't BAD, but i like the difference i see with a tank of midgrade 89.
The thing I am seeing the most is the effect of the temperature on my car, specifically economy dives of a few mpg when it gets real cold. I don't know if my LRR tires are a factor in that and cannot imagine getting snow tires will improve anything but safety.
That said the highest economy I saw all over the last 3 weeks was on a tank of 88, trying 89 today, seeing if that will at least offset the colder weather somewhat.
I am not concerned about HP or performance so much as fuel economy, I bought an SFE after all. The car, no matter the configuration, has more than enough power to pass and merge, that is all that matters to me. Highest HP car I have owned anyways.