[Turbomini]

i only run premium or if i am broke i will run 89 but i can tell a differnce in fuel mileage, my sundance gets 24mpg with premium and with 87(long story) it will only get 17 to 18mpg, my mini doesnt care what it has lol dont know why but it gets 22 with all fuel grades. but i still run 89 or better, the only thing i run 87 in is my 90 2.5 dakota just becuse it get better with the cheap it will get 21mpg with 87 and the other grades do the same so not a big deal,

 

[Turbomini]

It is worth testing your fuel economy at each level, but with the 4 and 6 cylinder cars I have had, I have found premium fuel made a huge difference with regard to fuel economy, while the V8s showed no real difference. If you're just cruising around and not getting on it all of the time, the lower octane is probably fine, but run a tank or two of each and record the results to determine if it is worth spending a little more per tank at the pump. For me, it has paid off.

lol i only tested the fuel at differnt levels in my truck becuse i was driving 5 hours one way and i had nothing else to do! LOL and with my van i was curious becuse i ran 89 and it was good so i tryed 93 and it didnt change? my sundance my mom put a full tank of 87 in it! well it lasted 2 days of driving.. and was spark knocking alot while driving.:bang head