Originally Posted by marlinspike
Where I am (both places) the difference in octane jumps is 10 cents/gallon, so that's $1/20 gallon tank saved if you mix it with 89...$1 buys half of a gallon of gas which is enough to go about 8 miles, or like getting an additional 0.4mpg. One could VERY easily get 0.4mpg more simply by doing the speed limit on the highway instead of the 10mph over everybody does.
That's part of my point exactly. In the old days (yeah, me and MM remember those) you could pull into a gas station, pop the cap, pump some from one pump and then go to another quite easily, then pay for both in one transaction. Certainly they were simpler times, more trusting, etc.
Now you would have to either walk in and give them cash for two pumps (assuming the clerk understands what you want and is in a mood to help out) or do two separate transactions, or run your credit/debit card twice at two different pumps, etc. I would think all this extra crap would probably double -- at least -- the time you'd spend pumping gas.
If you're really broke, then maybe your time is worth that small savings.
But if you're really broke, what in the world are you doing driving a premium
automobile that requires a higher pump octane?
Take care and enjoy the premium ride,