[wagsoja]

What are you guys using? The manual says minimum 89 but are you guys using 91? Thoughts? I have to fill up for the first time soon.

[MA78]

Originally Posted by wagsoja

What are you guys using? The manual says minimum 89 but are you guys using 91? Thoughts? I have to fill up for the first time soon.

Better re-read that manual.

"Required fuel
Super Premium Gasoline/AKI 91 or AKI
89
BMW recommends AKI 91 or 89.
Gasoline with lower AKI
The minimum AKI Rating is 89.
If you use gasoline with this minimum AKI Rating,
the engine may produce knocking sounds
when starting at high outside temperatures.
This has no effect on the engine life."

In OR, our premium is 92. And that's what I use. Use 89 at your own risk.

[wagsoja]

I did see that in the manual which is why I asked. Texted dealer and she said to just use 91 so that is what I am going to do.

[MA78]

Originally Posted by wagsoja

I did see that in the manual which is why I asked. Texted dealer and she said to just use 91 so that is what I am going to do.

That's the safe bet. Some people will tell you that you only need to use premium if you have a turbo, but that's BS. Your car will thank you for it.

[Nahoa]

Use the highest available. This engine will appreciate it. Usually $1.75 difference per tank. If you can afford the car and a Morning latte, you can probably cover the $2 per tank. You get a bit better mileage, when you want to zip it zips better, and it burns a bit cleaner. But, if you wanna save about $104 dollars a year, then the lower grade is for you.

[kozzi]

I use 91 or 93...depending on which station I'm at.

[tuco44]

I use at least 91 in my BMWs, and used 94 in my previously owned M3.

[sfax]

Do you use the same RON octane ratings as the UK? Our premium is 97-99. Why is yours only 92?

Is that why we're paying so much more for our fuel over here?

[flash3]

So basically use the highest priced gas they have?

[Razel]

RON=Research Octane Number. Basically, a calculated value. Generally a higher number
MOT=Motor OcTane. Variable compression head motor that is indexed to show real octane performance with an internal combustion engine. Generally a lower number.
AKI= Anti-Knock Index. RON*MOT/2 (average) Method used in the U.S.
91 AKI is generally 95 RON, but as it depends on the MOT value, it could change.
Nice way to advertise octane numbers, but keeps everyone in the dark as to what's really happening.
If you hear knock, go to the next higher grade.

[Nahoa]

93 is our premium here (generally). 89 is often the next step down, sometimes 91.

[stlgirl]

Yes, that's exactly right. Use the highest priced gas they have.

[wagsoja]

Stopped at the local Mobil and had to go with 93 for the first fill up as 91 was not avialable. I did notice on the pump it said contains 10% ethanol. Even if it is 93 octane, should I stay away from that Mobil and the ethanol content as I noticed in the manual it says that? Thoughts?

[roders]

Are F25's able to take Ethanol bend's? Here is Australia we generally only use 98 Ron for our BMW's. We are not able to use Ethanol blends.

[MA78]

My BMWs and MINI have done very well on Chevron.

[Beyu]

Can you guys in the states even find non ethanol gas anymore? It's pretty much impossible to find stations without a "up to 10% ethanol" sticker on the pumps.

Also the price difference between the highest grade and lowest grade of gas is minuscule even if you add it up over a year. It's the same reason why I never understood people who buy a hybrid "for the fuel savings." The savings over using just a normal petrol or diesel engine takes years in order to recuperate the upfront costs of a hybrid. I can understand someone wanting to get a hybrid because it's better for the environment since they're burning less fossil fuel and price for fuel doesn't represent the true cost of production and harm towards the environment but not when someone buys it for the so called money savings.

[wagsoja]

Originally Posted by Beyu

Can you guys in the states even find non ethanol gas anymore? It's pretty much impossible to find stations without a "up to 10% ethanol" sticker on the pumps.

Also the price difference between the highest grade and lowest grade of gas is minuscule even if you add it up over a year. It's the same reason why I never understood people who buy a hybrid "for the fuel savings." The savings over using just a normal petrol or diesel engine takes years in order to recuperate the upfront costs of a hybrid. I can understand someone wanting to get a hybrid because it's better for the environment since they're burning less fossil fuel and price for fuel doesn't represent the true cost of production and harm towards the environment but not when someone buys it for the so called money savings.

I think you are right about the 10% ethanol content being in most pumps now. My CA said that on avg there is 13% ethanol in most gas, so using 91 at a MINIMUM is safest to protect the engine.

[Lotus7]

Originally Posted by Beyu

Can you guys in the states even find non ethanol gas anymore? It's pretty much impossible to find stations without a "up to 10% ethanol" sticker on the pumps.

Don't be surprised to see those stickers being quietly replaced with ones that say: "Contains up to 15% ethanol" soon. On Oct. 13, 2010 the EPA caved in to lobbing pressure from a major US ethanol lobbying group "Growth Energy" to allow all pump gasoline to be diluted by up to 15% with ethanol. This was passed quickly, with little debate even though there was strong opposition from the auto industry. The auto industry has warned that a 15% blend may cause problems with fuel system components for any vehicle built before 2001, and should never be used for industrial and small engine applications.

FYI - The actual amount of energy you purchase in a gallon of fuel:
Diesel: 130,000 Btu/gal
Gasoline: 115,000 Btu/gal.
Gasoline/ethanol(10%) blend: 111,070 Btu/gal.
Gasoline/ethanol (15%) blend: 109,105 Btu/gal.

Current (Gasoline/ 10% ethanol) blends typically yield a 4 to 5% reduction in gas mileage compared to pure gasoline. The new “ 15% blend” will reduce mileage by approximately 6% minimum.

The major contributor to the “Growth Energy” lobby is Archer Daniels Midland Co. The day after the ethanol regulations were changed to 15% ADM stock rose 2%. Coincidentally, exactly the same percentage that the new (15%) blend will cost consumers in the U.S. because of the reduced gas mileage they will be seeing.

[Beyu]

+1 Lotus7

Not only a guy who's car savvy but someone who knows his politics and keeps up with it.

[Lotus7]

Originally Posted by Beyu

+1 Lotus7

Not only a guy who's car savvy but someone who knows his politics and keeps up with it.

In my case it's more than just "politics". My "fun" and track car has a fixed eprom map-based fuel injection system. When it became impossible to purchase pure gasoline in northern Illinois, I actually had to burn a new eprom map for the car to properly run on 10% ethanol at a personal cost of many hundreds of $ (took considerable dyno time). I'm not happy about all that work probably going "down the drain" due to the latest changes, and having to do it again.

Anyway, I'm just stating the facts. Draw your own conclusions.

[kmarei]

Originally Posted by Lotus7

Don't be surprised to see those stickers being quietly replaced with ones that say: "Contains up to 15% ethanol" soon. On Oct. 13, 2010 the EPA caved in to lobbing pressure from a major US ethanol lobbying group "Growth Energy" to allow all pump gasoline to be diluted by up to 15% with ethanol. This was passed quickly, with little debate even though there was strong opposition from the auto industry. The auto industry has warned that a 15% blend may cause problems with fuel system components for any vehicle built before 2001, and should never be used for industrial and small engine applications.

FYI - The actual amount of energy you purchase in a gallon of fuel:
Diesel: 130,000 Btu/gal
Gasoline: 115,000 Btu/gal.
Gasoline/ethanol(10%) blend: 111,070 Btu/gal.
Gasoline/ethanol (15%) blend: 109,105 Btu/gal.

Current (Gasoline/ 10% ethanol) blends typically yield a 4 to 5% reduction in gas mileage compared to pure gasoline. The new “ 15% blend” will reduce mileage by approximately 6% minimum.

The major contributor to the “Growth Energy” lobby is Archer Daniels Midland Co. The day after the ethanol regulations were changed to 15% ADM stock rose 2%. Coincidentally, exactly the same percentage that the new (15%) blend will cost consumers in the U.S. because of the reduced gas mileage they will be seeing.

i had read this was blocked

http://www.autoblog.com/2011/02/22/r...lock-e15-fuel/

[Lotus7]

Originally Posted by kmarei

i had read this was blocked

http://www.autoblog.com/2011/02/22/r...lock-e15-fuel/

Thanks for the ""heads-up". Looks like the House of Reps. saw the light and effectively blocked the EPA's slipping this one through (but only by a procedural maneuver). It will be interesting to see if the ethanol lobbyists try to buy some House votes and get it re-introduced.

Somehow, the notion of stretching auto fuel by raising food prices, and using more net energy to distill ethanol than it provides (even if that energy is from electricity) does not seem very smart from any point of view, except that of the grain companies who will turn a tidy profit.