# What fuel do you use?



## NC BMW Driver (Feb 1, 2008)

Starab said:


> Quote:
> Originally Posted by NC BMW Driver
> I fill up with 93, when I've used 1/2 the tank, I fill with 89, then when at 1/2 tank again fill up with 93 octane again.
> 
> Nice, But how do you keep track....


I just remember what I filled up with last. 
I suppose you could work up a system to help you remember, but so far that has not been an issue.


----------



## steveaccord (Mar 25, 2008)

*Octanes etcetera*



335i Driver said:


> I'm sorry but I'm going to ask you to prove that statement. There is absolutely no evidence that Top Tier is nothing but a marketing ploy no different that the internet bubble. It's my understanding that XOM does not want to be branded and Top Tier because they do not want to be restricted to specifications that are not up the par with their current standards. To state that Top Tier has 4x the additives of XOM is absurd.
> 
> If Top Tier is so great then why don't they release the specs required to be Top Tier? I would like to know their specs are for lead (ppm), Sulfer (ppm), Benzene %, Aromatic %, Olefin %, Hydrocarbon %, Oxygenate %, Heat of Combustion (MJ/kg), RVP (kPa).
> 
> ...


I absolutely second your position on the above. The benefits of premium gasolines are overrated in many ways. While I perfectly understand that BMW recommends the use of grades with octanes above 89 everything else id marketing fodder. Just to be as detailed as possible on the topic, the same BMW owners manual states that is possible to use even lower grades without sensible degradation of the engine performance save the occurrence of "knocking".
It is perfectly sensible that especially during hot days 'knocking' may occur using the regular grade (i.e. 87 octanes) rather than using the medium (generally 89 octanes) or premium grade (in excess of 91 octanes) because the higher the octanes specification the higher the 'anti-detonation' behavior of the gasoline/air mix in the combustion chamber.
Once again the 'knocking problem' as indicated in the BMW owner's manual is not addressed as a source of excessive wear and tear and mechanical problems, albiet quite agreeably I would not like to capture the extra noise as I love the growl of my 335Xi as it is.
Should any of you still linger on quite surreptitious assumptions that fundamental differences do exists between different grades of gasoline let me address the technical aspects of the used nomenclature. OCTANES refers to the racemic composition of the aliphatic chain molecules composing the fuel. In other words reflect the chemical composition in which the gasoline is refined to. In the specific case of OCTANES it suggest that 87 to 91-3 of the fuel is provided in molecule whose carbon backbone length is 8 carbon atoms long. Why such exact size predilection? Because based on such lengths are the combustion characteristics of the fuel. Having too much of a shorter backbone would expose to risk of Explosive like combustion, having too many of longer backbones would slow down the propagation of combusting the fuels therefore degrading the performance of a combustion engine.
To my knowledge there is an handful of engines (I think Ford produces some) that have the ability to sense the Octane content and adjust spark plug firing etc to optimize performance. That is the only circumstance where higher Octanes per se could add some zest.
Finally, as already suggested in similar threads, if I have to give any recommendation of what to fill your tank with, my best advise would be ....whatever is convenient to you and if it saves you some money...all the better.
Truly,

Steveaccord


----------



## ua549 (Oct 22, 2007)

Starab said:


> 7.76% for entire USA or just for your State?


Nationwide. The requirement is on the EPA website. The regulation was effective April 2008.


----------



## Klamalama (Oct 6, 2007)

bmw2006 330i said:


> I just bought a 06 330i. First bmw I have ever owned. Ive only bought gas once and just went with the cheapest(silver min octane 89) Any downsides to this? I know it says use premium gas only min octane 91.


As you have read herein, some folks bought their BMW for money. I bought mine for VALUE (I bought mine used). Having been endowed with the "thrifty" gene I can make the following recommendation:

Fill it 50% each of 89 and 93 octane... you get 91 exactly <<< genius!

If you have the "cheap" gene then you can go with 50% each of 87 and 93... which gives you 90 and is probably fine unless you're driving on the edge.

Keep in mind that when I asked a BMW salesman (nameless) what he recommended, he said that his dealership (nameless) filled their customer's new car deliveries with 89 octane.

That's life: roll the dice, take your chances.


----------



## WINDonSKIN (Nov 23, 2007)

billygoat777 said:


> y fill a mower with premium??


gas is sooo crappy that regular breaks down in less than a month, so since it sits in a 5-gal can over the course of summer, well you get the idea :thumbup:


----------



## Starab (Feb 17, 2007)

ua549 said:


> Nationwide. The requirement is on the EPA website. The regulation was effective April 2008.


Please give the details of the EPA website. thanks.


----------



## worldsmart02 (Dec 18, 2007)

I am using premium right know might switch to 89 later. BMW didn't said that premium is required.


----------



## Bmwcat (Jul 30, 2004)

Isa7913 said:


> Mmmm.... I know I tend to put my nose where I shouldn't, but I'll say it anyway.
> 
> That was a bit mean to say, but on the other hand you are right.
> 
> ...


Hey, the BMW looks awesome in the Taco Bell drive-thru though.


----------



## Bmwcat (Jul 30, 2004)

My 328 manual states that 89 octane is the minimum recommended fuel.


----------



## merchantmariner (Feb 28, 2008)

this subject is being beat to death. As gas prices increase and decrease (mostly increase these days) people will look for a reason to spend less. Yes the argument that "you bought a bmw, why wouldn't you pay for the recommended gas?" makes sense. You can rationalize pretty much any argument in the world. If YOU think that 89 octane is better in your BMW your not going to listen to anyone else anyway. Regardless, BMW has top german engineers designing their vehicles and engines. When they tell me the engines work optimally with 91 octane I listen. When an engine is designed to use a certain number of BTU's in a certain volume to produce the most efficient work the engine can produce, I listen. But, if you think your engine runs just the same on 87 or 89, who are they to argue. I suggest you buy a vespa.


----------



## TZH (Apr 10, 2008)

shell


----------



## mvallido (Feb 2, 2006)

Navy Exchange Gas here in San Diego when I had time to swing by the base. Other than that, I use Chevron. But of course 91 octane.


----------



## TX Buzzard (Dec 5, 2007)

Only use Top Tier gasolines! PERIOD!!!

http://www.toptiergas.com/


----------



## jcatral14 (Aug 4, 2003)

TX Buzzard said:


> Only use Top Tier gasolines! PERIOD!!!
> 
> http://www.toptiergas.com/


Wow and all the while I thought BP was top tier :tsk:
That's it then, Shell V Power from now on.


----------



## cdm (Nov 4, 2007)

I rotate between Shell, Chevron and 76 brands. Seems to work well.


----------



## 335i Driver (Nov 29, 2006)

TX Buzzard said:


> Only use Top Tier gasolines! PERIOD!!!
> 
> http://www.toptiergas.com/


I question the validity of a website that offers no information about itself and is as vague as that one. A quick who is lookup shows the the domain is owned by:

National Products Group.
PO Box 3475 
Tulsa OK 74101 US

918 836 8551

A web search for National Products Group tosses up the website http://www.nationalproductsgroup.com which is a company based in China that deals with polyester yarns. I can see the petroleum connection but I doubt it is the National Product Group that owns the toptiergas domain. National Product Group is a rather generic name so I'm sure there are more than one.

However, a web search of the phone number comes up with something interesting. That number shows up from several different sources as a number for a Quick Trip Corporation. QuikTrip Corporation happens to be a convenience store chain (I think convenience stores sell gas). They also happen to have the same PO Box 3475 and just happen to be located in Tulsa OK.

www.quicktrip.com

Phone numbers come and go when it comes to large corporations, as do PO boxes but due to the vague nature of the site toptiergas.com and the uncanny coincidence that it could very well be owned by a company that sells gas, I'm going to just consider www.toptiergas.com and the information it contains as a marketing scheme.


----------



## Z4 Steve (Jan 6, 2007)

All of my vehicles require permium gasoline and I use Shell or Union.


----------



## TambourineMan (Jul 25, 2007)

Anyone know why there are so few TopTier gas stations in Massachusetts? The pols here have got to have their hand in someone's pocket (besides all the taxpayers' as that is a given.)


----------



## Isa7913 (Apr 2, 2008)

Bmwcat said:


> Hey, the BMW looks awesome in the Taco Bell drive-thru though.


:loco: Are you sure you are looking at the right pic? 'Cause my X3 is in my driveway at home not in a Taco Bell drive-thru. But if you want next time, stop by my house and come and eat some Tacos 

To get back in the subject .... at the end you don't save much because you do more milage with premium gas anyway. And here in Montreal, in all Ultramar gas station, on Thursday the premium gaz is 3¢ less. So guess which day I put gas?!


----------

