[G80M3Noob]

I am in AZ it’s really hard to find 93 gas near me. Is Costco 91 good for G80 M3. Unfortunately it seems like the Costco has 10% ethanol

[ash_schwin]

My understanding is Costco 91 is ranked as Top Tier gasoline so I wouldn't hesitate to use it for my fuel up.

[SwankPeRFection]

Should be fine, these things will run on California piss 91 and all over the world without much issue, but if you tune, stick with 91 octane OTS maps when choosing which map to run. In a state where it’s hard to find 93, I wouldn’t even trust the 93 at those rare places as being good 93.

[G80M3Noob]

Will there also be a drop in performance

[SwankPeRFection]

Umm, yeah. Lol

The ECU will run less timing and possibly even slightly less boost, if necessary to keep things in check. That’s going to happen on a stock tune as well. It’s how things naturally work. Peak performance will only be realized if running good premium fuel, otherwise something has to be sacrificed so as not to damage the engine. Do remember that while octane is the important numerical value, QUALITY of said fuel is just as important. The same octane rating as some bullshit station may not be the same as another.

Don’t misunderstand, I’m not trying to scare you or discourage you from buying what you want, but if you’re going to buy a performance car (no matter what it is) and then put shit gas in it because it’s cheaper to do so, then I kinda feel bad for that car. Same rule for oil and oil change intervals. But ultimately don’t sweat it too much. Just buy gas from well known sources and I’m sure you’ll be OK, albeit a bit slower than peak performance out of the engine/tune you’re running, stock or otherwise.

[Mapper]

Originally Posted by ash_schwin

My understanding is Costco 91 is ranked as Top Tier gasoline so I wouldn't hesitate to use it for my fuel up.

except Costco 'waters' their premium gasoline fuel down with up to 10% ethanol.
I am lucky in my area that both 92 and 94 pure gasoline - no ethanol - is available from the pump from a few vendors.

[Mapper]

Originally Posted by SwankPeRFection

Umm, yeah. Lol

The ECU will run less timing and possibly even slightly less boost, if necessary to keep things in check. That’s going to happen on a stock tune as well. It’s how things naturally work. Peak performance will only be realized if running good premium fuel, otherwise something has to be sacrificed so as not to damage the engine. Do remember that while octane is the important numerical value, QUALITY of said fuel is just as important. The same octane rating as some bullshit station may not be the same as another.

Don’t misunderstand, I’m not trying to scare you or discourage you from buying what you want, but if you’re going to buy a performance car (no matter what it is) and then put shit gas in it because it’s cheaper to do so, then I kinda feel bad for that car. Same rule for oil and oil change intervals. But ultimately don’t sweat it too much. Just buy gas from well known sources and I’m sure you’ll be OK, albeit a bit slower than peak performance out of the engine/tune you’re running, stock or otherwise.

Bingo!
Further - 91/93 gasoline (octane achieved by adding ethanol) will produce less power than 93 pure gasoline.
Mileage - not that we care about it - also noticeably improves with pure gasoline. 3-5% more distance per tank.
Note that part of the issue is many stations will add UP TO 10% ethanol to achieve their octane- which will cause fuel Trims to have to constantly drift each time you fill up.

[M4Tejas]

https://www.toptiergas.com

ymmv

[Berzerker]

Originally Posted by Mapper

except Costco 'waters' their premium gasoline fuel down with up to 10% ethanol.
I am lucky in my area that both 92 and 94 pure gasoline - no ethanol - is available from the pump from a few vendors.

As far as I know, the vast vast majority of gas station you can find in the US (at least in the places I've lived) all say their gas "contains up to 10% ethanol" so it's not really that uncommon, and fairly difficult to find pure 93 or higher without getting it special.

[SwankPeRFection]

If you’re that hung up on trying to find non-ethanol containing unleaded fuel, go to a station that’s around an area where there’s lots of boaters. People that buy gas for their boats will usually have access to that and stations in close proximity to areas like this may carry it. This is easier said than done if you’re in a coastal state, maybe not so much in AZ, but it’s worth a check if you’re around a lake or something. Also, sometimes Sunoco will have options for non-ethanol fuels, but not always… depends on the station. I’ve had good success with Chevron and Shell.

[lilmanvc15]

I was shocked when I drove to New Jersey and they had 94 for premium. BMW had a little extra pep in its step thats for sure

[Autoaddict]

Do you guys like Sunoco fuels?

[mike@x-ph.com]

Originally Posted by G80M3Noob

I am in AZ it’s really hard to find 93 gas near me. Is Costco 91 good for G80 M3. Unfortunately it seems like the Costco has 10% ethanol

10% ethanol is normal. Costco 91 is fine.

Just keep in mind Arizona , California and Nevada 91's quality is lower than other states. if your tune offers ACN maps, i recommend you start with that. If the car is stock, you are fine, all 91 in the US are more than enough.

[Wtfitzvi]

you'll be fine with 91...if youre tuning and turning up the boost then you'd need to find 93 to higher octane.

[ryanm3]

Originally Posted by Autoaddict

Do you guys like Sunoco fuels?

Pump gas, probably not, my engine knocks after fueling with them (in Maryland), no noise when using Exxon or Shell. I'm sure there are multiple factors so cannot really say anything at the moment.

Race fuel, it is fine, or VP.

[Devils41]

Originally Posted by G80M3Noob

I am in AZ it’s really hard to find 93 gas near me. Is Costco 91 good for G80 M3. Unfortunately it seems like the Costco has 10% ethanol

I'm in PHX and you'll really only find 91 available since we share gas with California and Nevada. Tom's thumb sells 98 octane if memory serves and wild horse pass sells 100 octane.
I've run multiple trackdays on 91 gas just fine

[TopJimmy]

Our cars run fine on 91 Octane (91o) but they sure prefer 93o or higher, up to about 95-96o by my testing.

Ethanol is now the preferred octane enhancer used by the fuel industry because it costs less than other additives and works great at reducing knock. Many older cars had hoses and seals that were incompatible with alcohols but not modern cars like ours. Our adaptive fuel system can take advantage and add/trim without problems.

Reasons to like alcohol in your fuel:
-increased torque because of faster vaporization and a more complete burn
-alcohol produces water vapor during combustion, which absorbs heat, reduces knock, and also aids torque (denser exhaust vapor charge pushes piston harder)

Our stock tune can handle up to about 25% ethanol. I get best results at 20%.

___If you mix___ ___then you get___
14g 91o(E0)+1g E85 15g 91.67o E5.67
14g 91o(E10)+1g E85 15g 91.67o E15.0
13g 91o(E0)+2g E85 15g 91.67o E11.34
13g 91o(E10)+2g E85 15g 92.34o E20.0
12g 91o(E0)+3g E85 15g 93.00o E17.0
12g 91o(E10)+3g E85 15g 93.00o E25.0
**If you’re using 93o instead of 91o then ADD 1.6o to your “then you get” side.

[markoz28]

On my 2017 340i I’m on BM3 OTS stage 2. I run 10 gallons of 93 and 1 gallon of E85. Timing is clean and the car pulls. I just keep a 1 gallon container of E in the trunk at all times with a trash bag over it for smell.

[evidence]

If you end up getting tuned, plenty of places around the valley with E85-E99 paired with standard 91 pumps. Can easily make some spicy E50-E60 mixes at one stop.