Quote:
Originally Posted by iphanatik
thanks for the numbers, very interesting

If you like numbers, here is something I posted on another thread. You can use your numbers for what you are paying.
Around here Premium is consistently 20 cents higher per gallon. Here is what I am figuring:
36 gallons of Reg at $3.57 is $128.52 and I average right now around 16mpg. So on 36 gallons I can go 576 miles, divide the price for tank and I am getting about 22.3125 cents per mile.
36 gallons of Prem at $3.77 is $135.72, only $7.20 more. If I can just get 1 more mpg, then taking the same caculations, it comes out to 22.1765 cents per mile.
Now .136 cents is too close to really measure so if I end up getting 1mpg more than its basically a wash. But if you can get 2mpg more than it seems it would be well worth it for 20.9444 cents per mile. Of course if I get exactly the same then it's 23.5625 cents and considering I usually fillup about twice a month that could come out to $14.40 more per month.
I figure for $21 over a month of testing to see if I get any better mpg, it's worth the money just to see. If not, I go back to regular gas.