[Phaeron]

Originally Posted by alex2364

How can you afford a new BMW but not premium gas?

GOAL!

[Cyberdemon]

The irony is the person who wants to save a couple bucks on the fuel will probably then go and spend $1400 on a brake job at the dealer.

Reminds me of the guys you see in the hood filling up their escalade with $5 worth of gas...lol

[jasnh]

Originally Posted by dwalls90

The difference between 89 and 91/93 is often $.10 a gallon. You're only going to save $1.50 at full fill up. Scratch the candy bar and treat the car you bought.

But but..I gots to have my Milky Way!!

[Elk]

Run 89 AKI if you would like to save a little money.

Run 91 AKI if the 1% to 2% increase in power (perhaps 5 BHP at best) is important to you. As a data point, those cars with turbos which will run on 87 AKI to 91 AKI (such as the Hyundai Genesis) loose roughly 3% running 87 AKI.

You choose. The car does not care.

It is astounding how often this topic is raised.

[BavarianFanatic]

I really don't know what octane the gas I'm siphoning out of the cars on the block is. Is there are way to test it? I usually tap the nicer cars, but reading this thread has me questioning whether these folks are actually spending the $$ for good gas or if they're filling up with the cheapest crap they can find.

[1bad335]

Originally Posted by Elk

Run 89 AKI if you would like to save a little money.

Run 91 AKI if the 1% to 2% increase in power (perhaps 5 BHP at best) is important to you. As a data point, those cars with turbos which will run on 87 AKI to 91 AKI (such as the Hyundai Genesis) loose roughly 3% running 87 AKI.

You choose. The car does not care.

It is astounding how often this topic is raised.

Originally Posted by Yay-Z

I don't want to say the typical statement of "how can you buy such an expensive car and worry about gas" (guess I said it).

But typically high performance engines show lower efficiency with lower octane ratings. The savings you gain from the cheaper gas is eaten up by the higher gas consumption of the engine.

Originally Posted by Michael Schott

Who cares what the pumps are marked? BMW recommends 91 octane fuel for the 328 and 335 in the US. You can use 93 if 91 is not available but you earlier said they recommend 93 octane and that's wrong.

89

Originally Posted by Phaeron

GOAL!

There are some good points raised here and some points are made without really thinking them through. 89 is what BMW recommends as min octane rating. If you choose to run higher than that is great. If you choose to run lower, than you absorb that risk. As for the question of if you can afford this car you should be able to buy the higher octane fuel. I will simply say, read the post on this site concerning ownership and who is buying these cars. The point is you do not need ANY money at all to buy this car, you just need good credit to secure a lease or a mommy and daddy who buys the car for you. I don't care to debate how folks obtained this car but in the end let's not fool each other into thinking that if you own and BMW, gas prices are not an issue for you. The bigger question is if you can not afford fuel why are you driving a BMW and not a Prius. For me, I have run 89 in my e90 for 3+ years and I run 89 in my f30. Not a single issue to either car for 10's of thousands of miles. I throw in some 91/93 every now and again. It's not about saving the 2 or 3 dollars per fill up, it really comes down to the fact that I feel absolutely no difference at all using either grade. I stick to name brand fuels which tend to have better formulas and mixes. I don't track the car and don't really feel the need to wring out every last pony the car has. She is plenty powerful for me.

[Elk]

Originally Posted by 1bad335

It's not about saving the 2 or 3 dollars per fill up, it really comes down to the fact that I feel absolutely no difference at all using either grade. I stick to name brand fuels which tend to have better formulas and mixes.

An excellent plan and completely viable option.

[btbossman]

I have done some testing on my new 335i. A friend and dealer owner I know refuses to put anything but regular in any of his cars including M6. So on a trip to NY from DC last weekend I filled up with regular. The car felt great as usual and the gas milage looked good as well. On the way home I filled it with premium. The car felt the same from a power perspective, but the fuel range said about 20mi more range from the regular fill up. I will surely be doing some more research, but my friend said the recommended amount is 89 because the real minimum octane is 87.

[Mark_K]

What is REALLY curious to a detached observer is that this discussion comes up regularly and heats the spirits very easily - all in a country where "bigger is better" , "two is better than one" , "I don't need 7 seats but I might need it" ... and so forth. Each one of those above has more serious consequences (monetary and otherwise) to a person making them and society as a whole, but that doesn't matter. No, we will debate to death something that has minimal impact and is actually a no - brainer.

See vitamin C, for example. It is one of the rare substances that you can abuse all you want without consequences. Recommended intake is around 1.5 grams a day, but if you take 5 grams a day, you'll just p|ss it out without damage to any organ. HOWEVER, taking chronically LESS than 1.5 g/day might give you scurvy at the end. Same with octane. If in doubt, premium's extra octanes will just go out of the pipe without consequence, but lower than optimum octane might seriously damage your engine in the long run.

Why are we discussing this for 1,000 th time again?

[bizzyqu]

Originally Posted by BavarianFanatic

I really don't know what octane the gas I'm siphoning out of the cars on the block is. Is there are way to test it? I usually tap the nicer cars, but reading this thread has me questioning whether these folks are actually spending the $$ for good gas or if they're filling up with the cheapest crap they can find.

you win

[AstonKarim]

I have been using 94 octane, but just recently found out that there is 10% ethanol in it. Is this still ok to use? I think ethanol is being added to all fuel mixtures and will be hard to avoid.

[BavarianFanatic]

Originally Posted by AstonKarim

I have been using 94 octane, but just recently found out that there is 10% ethanol in it. Is this still ok to use? I think ethanol is being added to all fuel mixtures and will be hard to avoid.

You won't be able to avoid the ethanol-laced fuel. There's no harm other than a shortened shelf life.

[Blacked out 2013]

Originally Posted by CirrusSR22

The F30 owner's manuals are up on BMWUSA and the section on fuel gives no "recommended" fuel octane. It only says the minimum is 89 and do not use less than that minimum.

We need someone with the actual car to tell us what the fuel door says.

In the specifications section of the manual it does say that the listed power outputs are based on 91 octane.

I have a brand new 2013 335, and the fuel door says "minimum 91 octane" premium gas.

[overkill1125]

I always used 91 since day 1 and after reading this thread I filled up from empty with 89 for my own testing just to see if there was any difference. 2 days later I can hear the engine sounds different at idle during traffic hours. Not sure if its knocking sound but it sounds different from the usual since i had the car since march.

I can't wait to finish this tank and refill it with 91 and I HOPE that it will go back to how it was before.

[Kowboi]

Originally Posted by alex2364

How can you afford a new BMW but not premium gas?

+1

[bavarianboar]

Chevron Supreme. Like no other.

For me the test is, how much the car revs in lower gears and on cold start. I notice a significant difference even between Shell and Chevron. Costco gas is a joke in our cars.
Always filling premium but still the difference is quite noticeable, owing to the cleaning agents if I believe ALL Oil is born the same.

87 to 89 to 91 to 93, I would expect significant difference in lower gears, maybe not so much at highways speeds.

Just my 2 cents.

[AstonKarim]

Originally Posted by BavarianFanatic

You won't be able to avoid the ethanol-laced fuel. There's no harm other than a shortened shelf life.

thanks, good to know!

[Kabrich]

Originally Posted by BavarianFanatic

You won't be able to avoid the ethanol-laced fuel. There's no harm other than a shortened shelf life.

Actually, I have only put non-ethanol fuel in my 335 in the few fillups since I have had it - and it is A LOT more expensive than normal premium.

Anyone looking for "Pure Gas" can find a "Pure Gas" iPhone App (perhaps Android as well) which can show you where "Pure Gas" is available near you.

I was about to ask the question, but since you posted this here, is it better performance (engine and mpg) for non-ethanol "pure gas"?

Second question, as someone else posted in the previous 4 pages, in the USA is 91 AKI = 91 Octane or is 91 AKI = 93 Octane?

[Elk]

Originally Posted by Kabrich

. . . is it better performance (engine and mpg) for non-ethanol "pure gas"?

Gasoline has a higher energy content than ethanol. Thus, the car will get slightly better mileage on 100% gasoline than on a 10% ethanol mix.

. . .in the USA is 91 AKI = 91 Octane or is 91 AKI = 93 Octane?

91 AKI is 91 octane. AKI is the measure method used in the States.

[jelecroy]

Originally Posted by CirrusSR22

It says the minimum octane is 89 which is mid-grade. You do not need to use "premium" which is usually 91 octane. Basically, just don't use regular 87.

Atually, the OM also says:
Engine specifications
The rated power outputs are established on the
basis of fuel grade AKI 91.

So the engine will SURVIVE on 89, but will make rated performance on 91 or better. Where I live, most regular gas is 87 AKI, and mid-grade 89. I buy 91-92 AKI premium, and find about a 10% improvement in gas mileage when I can fill up with ethanol-free gasoline.

[Kabrich]

Originally Posted by Elk

Gasoline has a higher energy content than ethanol. Thus, the car will get slightly better mileage on 100% gasoline than on a 10% ethanol mix.


91 AKI is 91 octane. AKI is the measure method used in the States.

From that, you seem to be saying that putting 93 Octane Premium Gas in is overkill and just wasting money, compared to 91 Octane, correct?

[Elk]

Yes.

There is no benefit to running higher octane fuel.

Originally Posted by jelecroy

So the engine will SURVIVE on 89, but will make rated performance on 91 or better.

The engine will more than survive on AKI 89; it will run perfectly happily.

The power loss is minimal, 2% to 3% at most on a turbo charged engine - nothing a street driver is going to feel by butt dyno.