[hornedav]

Hello,

Can 2015 BMW 320is run fine on Standard unleaded fuel (91). Any implications with long term use of this octane rating?

Or use only premium unleaded (95 and 98) only?

Thoughts?

Thanks in advance.

[x328x]

I would use whatever is recommended by BMW. Usually its stated on the fuel cap. Unfortunately not sure what it is

Personally i have always used 98. But now that i am running a tune with higher boost higher octane is really important.

However you need to put things in perspective

if you do 20,000 km a year, and you average 9L/100km that ends up being 1,800L per year (20,000/100 x 9)

98 octane is about 10 cents to 15 cents more than 91 Octane. Lets say 15 cents

thats an additional 270 bux a year in fuel.

[hornedav]

Thanks x328x. Cheers.

[chet82]

98 every time , my non franchise local fuel station stocks 91 or 98 and its always cheaper fuel at them . knowing the place the tanks have been replaced about 4 years ago so its all good .

BMW recommends 95 and above or Ethanol based 91 if remember correctly .

[bradsm87]

No. Do not put 91 RON in a 11:1 compression ratio boosted engine.