Same here - Premium Only for my E39 and E60. If you're looking for cost savings, use a credit card that offers anywhere from 3% to 5% cash back rebates for filling gas! Cheers!

 

But if you add that on top of the $0.30 I save by using regular gas or better yet... costco regular gas I'll be saving even MORE!

 

See this thread.

http://forums.e60.net/index.php?showtopic=56353

 

The higher the octane, the higher the resistance to igniting. Detonation, pinging, and knocking are all caused by a fuel mixture that is not waiting for the spark plug to fire before it ignites. Most cars can change their own ignition timing to account for users putting in cheaper fuels (lower octane) than are recommended.

 

Costco sells gas? lol where have I been

I can only imagine the lines there, which is why I never go there..

btw, premium buddy. Sorry , this is a BMW, unless you really hate your car or its a lease, do what you have to do to make ends meet..

 

my car is a lease and i treat it as if were going to be mine to own. Lease or Financed, spend the money and get premium. For those that are leasing, that's no excuse to skimp on the gas, think of it as karma. Would you want a fellow e60 member posting about his/her newly acquired CPO's/used e60 only to find out the engine and performance is all jacked up because it's previous owner really couldn't afford to maintain it. As stated before, if you can't afford to maintain it, why are you even driving it?

 

I did a pretty long test on the diff on 87 89 93 in the chicago area. outcome. It all cost about the same. Less gas mileage on the lower grades, lower cost but more fill ups. More mileage on the higher grades Higher cost but less fill ups. This was a 4 month test.

 

Interesting. I think I will do an experiment over the next couple of months with 92 versus 94 and see mileage/cost. Although if I feel any increase in performance with 94, the test will end immediately regardless of any cost benefit..