Originally Posted by DJ Apex
so aside of this he said she said bs who know the truth u say one thing i say another so who knows. And do u have headers? Have u done the off road tune or this new AA tune? Ive done the math and driving non granny style i get 11 mpg so i really have a hard time thinking raising my oct 5 points is gonna give me 10 more miles per gallon! ive ran 87 oct befor this mod and still avg 18-19 mpg that was with the AA tune! So i just put a full tank of 93oct today and guess what avg 16.6mpg! lol not useing the cars mpg reader thing this is doing the math after filling up again!
so since i see no imporvment in mpg i dont see the need to spend 40 cents more per gallon when i get the same millage eather way. its not about being cheap but if i get the same millage from 87 oct and 93 oct kinda makes me think its not fule. thats why im leanin to something else might be wrong witch is what im dealing with now.
smiles high five
I am quite sure the higher octane gas is stipulated by BMW for internal components of the engine. It was explained to me beforehand but I can't remember the exact reason. Using a lower grade will have a bad effect on your engine over time. Call BMW and ask a SA or a tech. They should explain it. This would mean tune or no tune, good mpg or bad mpg the higher octane should be used.