ARCO vs. Costco gas

[Durango]

Hello to all and a good Mothers Day to you,

Please settle a small issue/opinion between myself and two of my co-workers. As far as quality of gasoline is concern they both say ARCO gas is tooo watered down and burns too fast from theirr tanks during the regular workweek. They say "Costco brand is much better and would rather use that instead"!!!! I for myself believe the opposite BUT must admit I haven't had any issues with either brand. In my truck it takes regular and my car supreme.

What would you California guys/gals say-opinion.


Durango

 

[rshaw125]

The only way to know is to do regular checks of actual mileage. As opposed to what you think it maybe. Otherwise it's just anecdotal.
Where I live it all comes out of the same pipe line near I-95.

 

[Johnny248]

I don't know what ARCO gas is. However, I can tell you that I have consistently seen 40-50 miles per tank less when using Costco gas over the other brands. I try to use Shell gas (if I can find a station when I need to fill) but also end up using BP and Mobil quite a bit because station location. Anyway, my gf who works at Costco tells me that the trucks that fill their gas station say BP on the tankers. That is at least here in my area. No idea what fuel is actually in the trucks. I'm sure they are filled with what ever fuel the Costco orders from the supplier. Don't know enough about gasoline to be able to explain why one brand fuel would provide better fuel mileage, but I have seen this happen at least 8-10 times using the Costco fuel. Driving habits are pretty much the same will all fills. I drive to work, drive home, occasional trip to the store. All I know is I get more miles per tank not using Costco fuel.

 

[Boomer]

Almost all gasoline in a given area comes from the same tank farm/supply line. As such there is NO difference in the base fuel. Additives do differ and they are added as a truck fills up. If the fuel is Top Tier (see their Web site), you are gettin a higher level of additives than required. Since the fuel is the same in an area,and only the additives differ, I always find these anecdotal stries of wild mileage changes to be on the side of urban legend.

I have kept very careful track of mileage in my cars and trucks and really don't see this. I do see a difference in my Nissan VQ 40 engine depending on octane grades as it is set up for running on 91+ octane fuel. It may be that some styations are having a lower octane fuel put into their super tanks but that is illegal.

 

[JHZR2]

There could be a different alcohol content, otherwise define "watered down".

Without statistically significant controlled testing little can be figured.

 

[MrBeachcomber]

Your experience is similar to mine. All our gas in my area of the country contains 10% ethanol due to air quality standards. The ethanol is mixed in locally as was shown when COSTCO and all the other local discounters ended up with too much ethanol (about 40% instead of 10%) in the local fuel a few months back.

When I was working with my brother and nephew in Knoxville, TN back in 2007/2008, I was able to fill my tank with ethanol-free gas. I averaged much better mileage in the city and Interstate driving during that time frame than I do now.

 

[ahoier]

More gas content to less adpack, results in higher MPG?

OR

Perhaps more adpack (better cleaning?) to less gasoline content (lower MPG?) results in the lower MPG rating for the fillup?

Though, if you believe the hype of gas marketing (those dirty fuel injector pics) - I'd think the "higher adpack" would result in more cleaning power.

I know in my experience of using Shell, my Shell fill ups tend to have lower MPG ratings than "other" stations I use....I'm not too familiar with the gas pipelines/refineries in my area, nor do I track which trucks drop off gas at each station, but something has me thinking it's something related to the first instance.

For example, Shell, claims they got their special adpack to keep the injectors and intake "cleaner" (to what? who knows...lol) - so perhaps their gasoline/fuel content is "less", which alters the burning rate of the gasoline to result in lower MPGs, but cleaner internals?

Who knows....lol.

But yea, alcohol/ethanol content plays a roll too...most stations here post signs "may contain UP TO 10% ethanol" - so one fill up could be 8%, another tanker could be dropping in 5%, etc.....though from reading around at gasbuddy, many posters have stated this circumstance highly unlikely, since the refineries likely get a higher "credit" for using the higher ethanol content in their gasoline....so it's more likely they'd "max out" that credit, than skimp out on the ethanol content.


For MPG there's just so many variables, warm up time, how you drive, oil weight/type/brand, etc.

 

[2oldtommy]

Durango, I was under the impression that all gas in CA was identical in that CARB dictates the chemical composition of all motor fuels. That said, whether you buy it at Arco or Costco it still will have an oxygenate, (alcohol 10%) in it. Am I missing something that CARB has now changed the rules to allow the use of alcohol as an option at the discretion of the retailer?-- Oldtommy

 

[Johnny248]

Originally Posted By: Boomer
Almost all gasoline in a given area comes from the same tank farm/supply line. As such there is NO difference in the base fuel. Additives do differ and they are added as a truck fills up. If the fuel is Top Tier (see their Web site), you are gettin a higher level of additives than required. Since the fuel is the same in an area,and only the additives differ, I always find these anecdotal stries of wild mileage changes to be on the side of urban legend.

I have kept very careful track of mileage in my cars and trucks and really don't see this. I do see a difference in my Nissan VQ 40 engine depending on octane grades as it is set up for running on 91+ octane fuel. It may be that some styations are having a lower octane fuel put into their super tanks but that is illegal.


I don't agree on your urban legend. I've never noticed any difference between a top tier such as Shell and just a name brand like Mobil or something. I remember watching something on Discovery maybe about how the fuel system works.

The fuel company deposits whatever grade fuel it may be (say 91 for instance) into the pipeline. They run through the pipelines and each unit is sepperated by soemthing thing called a "pig" that seems like a big plunger or sealed devider.

So Company "A" deposits 100 units for instance, and Company "B" deposits 100 units, and so on. Well, at the other end, company A will withdraw 100 units from the system, though it would not be the same 100 units that they deposited. But it does not matter, because at that point company "A" takes it's units, adds it's additive packs, and cleaners, or whatever their formula is into the fuel and then ships it out to the stations. So Mobil's end product would differ from Shell, and Marathon, or whatever company is shipping it to their stations. I'm sure at that point, one company prob has a higher quality additive package than another one.

Anyway, back to the original urban legend. My experience is totally unbiased, but I can tell you that I drive m-f ~30miles each way on the same roads, at the same time, with similar traffic. Again, I may make a run here or there to the store or something. But at least in my car, I consistently get aprox 380-400ish miles to a tank when I'm using corner station "house hold names". And I consistently get about 340-350ish out of my tank when I fill up at the Costco by my house. So to me there is something different. It may not effect everyone the same way, but for a fact which I have duplicated over and over, I just don't get the same distance out of the Costco fuel. As far as I knew, say here in Michigan, the fuel can't contain more than 10% Ethanol unless it is E85 or something. I don't see how some companies could double up, or add more ethanol and get away with it with with all the certification stickers I see all over the pumps that get updated.

Either way, to save 5-10 cents a gallon at Costco just means that I have to fill up a day or so earlier than I do when I'm using other stations gas.

I supposed that is not totally scientific, but it also is not just me being so in love with a certain brand product that I try to always look and promote how much better it is, as some people like to do with their expensive oils and whatnot.

 

[Vizzy]

I tend to agree with the fact that for specific regions the gas that comes out of one pipeline is going to the ENTIRE region so the base fuel is EXCACTLY THE SAME. Where the differences come into play are :

1) The condition of the individual stations tanks, pumps, and filters....thesedays it is VERY unlikely that water enters into fuel because of the tight controls involved.

2) The detergent additive packages and any other proprietary chemistry that is added.

Those might play a role in economy, but my guess it that overall it is usually insignificant.

 

[Durango]

2oldtommy,

I believe you are correct regarding California standards but my issue is not a scientific one at all. It's just a generalized opinion of what my co-workers said.

Again they believe you won't get as good of MPG using Arco because they saif it's "watered down" gasolinebut another co-worker said he'd rather use Costco over Arco due to the same belief. Personally I've never had any issues using Arco at all in MPG or engine performance.

Durango

 

[Thomas34]

Originally Posted By: Vizzy
I tend to agree with the fact that for specific regions the gas that comes out of one pipeline is going to the ENTIRE region so the base fuel is EXCACTLY THE SAME. Where the differences come into play are :

1) The condition of the individual stations tanks, pumps, and filters....thesedays it is VERY unlikely that water enters into fuel because of the tight controls involved.

2) The detergent additive packages and any other proprietary chemistry that is added.

Those might play a role in economy, but my guess it that overall it is usually insignificant.


my dad works for Conoco Phillips. this is exactly what he says. the additives are what makes the fuel different from one another.

 

[BearZDefect]

I have noticed mpg differences too, and have another idea to add:

First, the difference in mpg seems far more significant when using premium than using regular unleaded.

I've noticed that around here, premium at some stations is 92 octane, at others it is 93 octane.

91 octane is recommended for my 1997 i30, so either 92 or 93 is more than enough. But there must be some difference, because I get nearly solid 10% better mpg with the 93. The 92 gives the same mpg as 87 in this car.

A friend of mine with a much newer car (2005 TL) that also requires premium reports the same mpg difference.

I doubt the 92 stations (many are corporate owned like Speedway and Pilot) are putting regular in their premium tanks.

My current hypothesis is that the 92 octane is achieved using cheaper gasoline and more ethanol than the 93.

 

[Ken2]

Quote:
the additives are what makes the fuel different from one another.

A few years ago I way buying about $500,000 of heavy fuel oil every five weeks. We hired a gauger to measure the quantity of the fuel both in the barge tanks and in the ship's tanks, and to take a fuel sample to the lab to see that it met spec.

One gauger we worked with frequently told about working for the local refineries. The refineries occasionally buy, sell, or trade product with each other, and he was often called on to test the product. He said that ARCO was the only gasoline that was below spec. The others re-blended the ARCO gas and adjusted the price paid to ARCO. This was before BP bought ARCO, so maybe things are different.

BP/ARCO is the only gas where I can see the gas gauge drop faster than any other brand including the supermarket brands...I haven't tried Costo.

I'm joining in the boycott of BP/ARCO/Castrol products. They did not use the best available technology in their drilling, and they hired the contractor with the worst safety record.

 

[Durango]

Hi Guys,

OK I understand all gas comes from the same pipe and the difference between brands is the additives. OK, Arco is one brand and it's additives "clean tech" is what makes Arco gas so unique. Where does Costco gasoline fall in???? This is discount gasoline so what additives are added in this gas?

Can you guys speculate why my co-workers prefer discount gas ( Costco) over Arco??? If brand name gas is important then why isn't Arco so liked?

Durango