Yes 87 is "acceptable" just as is riding on your donut spare. But it is not recommended. I don't believe any corporate advertising. I believe in the facts and it has nothing to do with BMW, any high performance engine will do better with higher octane gas. When I had a Honda Accord, I used regular. I will not use regular in the 550. "Regular octane is recommended for most cars. However, some cars with high compression engines, like sports cars and certain luxury cars, need mid-grade or premium gasoline to prevent knock."


So again, do what works for you. Or publish a controlled study that is accepted by the EPA and I'll roll with you.

 

I have a question about your 87 gas, Does it contain any ethanol? Does valero use ethanol to increase the octane rating of the higher level gases. I ask this simpley because ethanol does increase octane but does reduce the energy contained in the fuel. If your station has 87 without ethanol and the 89/9x does contain ethanol, that would be the reason for your increased mileage. I have filled up at gas stations near heavy boating areas which has pumps which specifically state there is no ethanol and is directed tward people with boats. Ethanol absorbs water and most boaters that I know make sure they get non-ethanol gas. Every time I use 100% Dino fuel, my mpg jumps a bunch.

 

so what part of "this has no effect on the engine life" do you find incorrect and/or unproven?

10% ethanol.

 

The only thing that proves to me, and probably others is how cheap you really are and the BS in your posts.
cheers
vern

 

I'm with Luigi on this one. I don't mind paying extra for 91 octane. If you're concerned about getting better mileage maybe this isn't the car for you. Perhaps consider a Toyota or Honda as your next vehicle.

Anyway, speaking of higher octane. How does everyone feel about 100 octane? I tried it a few months back at about $8 a gallon but didn't notice any difference.

 

When I fill up on 89 my digital cluster tells me that i have more miles available per full tank than on 93.

lol

Do you think EPA is not controlled by corporations along with everything else?


OP - Once my old Economics professor did explain the theory of gasoline and the octane ratings and also about the corporate hand in it and also the entities establishing the rules that govern it. I don't remember everything but i can tell you that much of the world is fooled. I personally have never used 87. The lowest we have in my area is 89 and I run that like once in every three tanks just to check it out. When I had my old E46 323i (which was a 325 renamed for BMW's advertising purposes....had the M52TU 2.5K engine) I used 89 after I noticed increase MPG and performance with the 89 Octane. It was also easier on my pocketbook.
I personally use 91 and 93 exclusively now because I do care about the car and the next owner to be quite honest. I've already given it tender care so might as well finish it off until it's no longer my vehicle. Really the car is metal, glass, plastic and rubber so who gives a shit? But I'd like to keep any issues down because I would like to retain my resale value. Fact is most of these people are brainwashed. I'm not one of them but when you're selling to a brainwashed person you have to understand them and find their angle. Personally I'm trying to let go of a lot of things that are material in nature.
So like I said before (I think I said) if you want to run 87 or 89 go right ahead, I don't think it really matters. For me, i don't care enough to educated myself in something that is never ending and very 'worldly' ....after all it involves primarily money right? How much money can I actually save in a lifetime? Or rather in this car's lifetime? Not much so personally I don't really care. I'd rather educate myself in things that will matter to me in life. And if i can get ahold of a late 80's pickup bare-bones this definitely will not help me. I have to agree with most of what you said especially after seeing the documentation around it....keeping in mind the facts about corporations etc.

 

the only thing I use is 93, honestly how much can you be saving with 89. If you have the money to buy a BMW than money spent on gas shud;nt be an issue

 

i don't mean to be rude, but that truly is not the argument. i do well for myself and money is not a concern, however in the 9 months i've had the car it has been in the shop for more reasons than are expected from a bmw. i truly just don't like the car anymore and do believe is prone to problems; simultaneously, the research i have done shows 87 may cause knock, but even knock won't hurt the engine. since i have lost the respect for my bmw, i really don't care about knock. saving money off of an expense that has already gone wrong seems like the totally logical thing for me to do.

adding 5-6mpg is an added bonus. some of you guys that fail to read or just like to be judgmental really come of as morons.

 

I did an experiment this week.

I did a lot of in town driving with a little long distance (~200 miles) of high speed freeway driving. I drove very spiritedly. I filled up with 93. Got 22 MPG.

Then on a long journey of high speed freeway driving (+200 miles) I filled up with 87. I drove like I used to with my old Prius: hypermiled as much as I could and eased on and off the gas. The only thing I noticed was a lack in get-up-and-go. I heard no knocking. My mileage for the trip (with 87) was 25 MPG.

RE: morons. The problem is that you've purchased a car that 90% of the folks here don't know how to/can't work on it. Their only answer is going to be "take it to X" which leaves a lot of room for opinions. There are other forums, like rv3 and pointedthree, where the focus is on older models and requires more *real* knowledge. Hang in there.

 

+1 well stated. Now let's move on.