gasoline - at the pump differences

[mikep]

I would love to get a discussion going about the various major gasoline brands widely available across North America and the differences in their additives/detergents. Mobil has always advertised their detergent qualities. I've read posts here that Shell has some good additives and Chevron supposedly has Techron in it's pump gas but I've not seen any real concrete evidence or posts to suggest this is all very real.

So is there any real data to suggest the majors are different given the same octane rating? Shell, Exxon, Texaco, Citgo, Hess, Amoco(BP), Sunoco, Mobil? We all know the gas flows through the same pipelines and is co-mingled but I was always under the impression that the additives are added at the terminals and loading racks?

Is there one best gasoline based on it's additives or detergents?

Mikep

 

[eljefino]

The differences are regional-- fiftysomething different regions IIRC. exxonmobil (?) has a nice map somewhere on their website. You've also got lowered vapor points in the summer, boosted in the winter. I'm sure the additive package must be changed to compliment these "base stocks" and everyone dips in everyone elses' pool for smaller "boutique" markets.

On worldwide/nationwide bbs's, this usually boils down to "use what works in your car/area", "MTBE/oxygenates are lousy and cut mileage" and "I like the techron that comes in chevron".

 

[MikeySoft]

I have a newer Honda Accord. I put over 650 miles a week. I buy gas at a local gas chain in CT and a different local gas chain in MA. I use these chains because they are convenient and have low prices. I was under the impression that all gas is the same.

However, on 3 occasions, after buying gas at the local MA chain, my check engine light came on between 1 and 30 miles after putting the gas in. The light goes off after 3 driving cycles. This never happens when I buy gas at the different chain. It was NOT a loose gas cap!!

The OBD code is P0420, "Catalyst System Efficiency Below Threshold (Bank 1)". I also look up this code in my shop manual. It said that this code could also occur by "Bad Gas". But it does not say what they mean by "Bad Gas"

Any comments if this could be the gas and what is "Bad Gas"?

I have an appointment with the dealer this week to look into it.

 

[JonS]

I found out that my Jeep doesn't like Mobil gas. It runs like crap on it. I tend to use Amoco because i feel it is better and is more convenient for me.

 

[mikep]

quote:

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Originally posted by JonS:
.....I tend to use Amoco because i feel it is better and is more convenient for me.

---

Exactly why I started this thread. Convenience is one thing and feeling the vehicle not running well, as is the case with your Jeep using Mobil, is another point. Both very understandable. But the "I feel it is better" is the kind of thing I want to get at. Why is it you feel it's better. Granted your Jeep runs well on it, not like the Mobil. But I'd be willing to bet your Jeep would run just as well on Shell or Exxon or Sunoco.

If there are 3-4 differnt brands of gas that ones vehicle seems to run well on is there any other reason to have a preference of one over another (politics and personal agendas aside)? There has to be some x-factor in additives and detergency

. If not then how can company X differentiate their fuel from company Y?

Mikeysoft.....getting a tankful of tainted fuel every now and then is not uncommon. But 3 times from the same station is very suspicious. Almost sounds to me as though they have a leaky underground tank which is letting moisture into the fuel. Either that or their tanks are sludged up with excessive condensation and every time they get a delivery all that crud gets stirred up and pumped into your car. The pump filters could also be suspect...or even missing? Given your experience there I would avoid that station like the plague!

 

[pinoy99]

My truck gets better MPG with Exxon/Mobil vs off brand like WaWa gas but otherwise runs the same. Does it mean that the other have better additive? Probably but the off brand one is a dime/gal cheaper so that justify the use of #131 which bump up the mpg. Convience in Jersey is not an issue since there is a gas station every corner. I use mostly the 2 mentioned above.

 

[MikeySoft]

quote:

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Originally posted by mikep:
... Given your experience there I would avoid that station like the plague!

---

I agree and will not use that gas station again. It may not be the gas but why take the chance.

They are 5 to 10 cents cheaper then the other stations so they have high volume. I hope it is not a leaking tank because I believe MA uses that additive (don’t remember the name) that is really bad for ground water.

Drivability and mileage does not seem to be affected by that gas or when the check engine light comes on.

 

[Whimsey]

Even though many brands of fuel start from the same delivery depot the differences supposedly come at the loading rack as Mikep pointed out. It would be interesting to find out what gas stations in a particular area share the same loading depot. I don't have any brand loyalty, just convenience and price when I need fuel. Having said that I have noticed that with certain brands in my area I do get less mpg. For me Amoco/BP, Getty and Hess give me the worst mpg on a consistent basis. For Exxon, Mobil, Gulf, Shell and Texaco it's pretty much a toss up for mpg. Every once in a while I'll get a tank of gas from one of the stations I frequent that causes the truck to run "not so swift". I think that from delivery to delivery at the same station the quality of gas can vary.

Whimsey

 

[Jimbo]

Here in the Los Angeles area, every major oil company has its own refinery, ChevronTexaco, BP(ARCO), ConocoPhillips(76), ExxonMobil, Shell, and a host of smaller names. Because of the air pollution requirements, the formulas are very much alike. My cars and trucks run pretty much the same on all of them. Shell's "higher mileage" is a joke. I tend to buy low price and convenience with a bias toward Chevron because of the Techron.

 

[edhackett]

A few years back when we were first getting our FTIR system set up, I looked at a couple of gasolines. I grabbed a sample of Chevron and one from a local no name mini mart. Both were 87 (pump) octane unleaded. Analysis showed the two gasolines to be very different. The no name stuff was composed mostly of straight chain molecules. The Chevron contained a high percentage of branched and aromatic compounds. The Chevron was blended from a higher quality distillation cut.

Shipments of gasoline, even though sent through the same pipe, can be separated by "pigs" and sent to individual tanks.

Ed

 

[TooManyWheels]

Let me mention a couple of points which I know from relatives who work in the fuel distribution business.

At the oil company level, refinery production often does not match retail demand. Since premium gas can be sold as regular, but not the other way around, the refineries always weight their production slightly toward the higher grades, then sell it as the lower grades where necessary. This is one place where you tend to benefit by buying from a major.

In the distribution to the stations, several things to be aware of when you talk about independent stations and convenience stores. The first is that the seal between the tank's filler neck's and the pavement are sometimes not good, depending on how well the property is maintained. Water collects there, waiting for the filler to be opened, and then does what it does when that happens. Also, store operators sometimes very deliberately order more Regular than they have tank capacity for, knowing that since the driver gets paid by the delivery, he may be able to be talked into dumping it into the higher grade tanks, even though he faces a stiff fine if caught. These two factors seem to relate directly to a general "sleeziness" of stations.

The morals of the story: Give some thought to where you buy gas, and don't blame everything on the oil company.

 

[Robbie Alexander]

quote:

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Originally posted by edhackett:
*-*-
Shipments of gasoline, even though sent through the same pipe, can be separated by "pigs" and sent to individual tanks.
Ed

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Sometimes and a lot of times with fuel, there are no PIGS, they are just butted up against the last shipment in line...

 

[mikep]

quote:

---

Originally posted by TooManyWheels:
Let me mention a couple of points which I know from relatives who work in the fuel distribution business.

At the oil company level, refinery production often does not match retail demand. Since premium gas can be sold as regular, but not the other way around, the refineries always weight their production slightly toward the higher grades, then sell it as the lower grades where necessary. This is one place where you tend to benefit by buying from a major.

In the distribution to the stations, several things to be aware of when you talk about independent stations and convenience stores. The first is that the seal between the tank's filler neck's and the pavement are sometimes not good, depending on how well the property is maintained. Water collects there, waiting for the filler to be opened, and then does what it does when that happens. Also, store operators sometimes very deliberately order more Regular than they have tank capacity for, knowing that since the driver gets paid by the delivery, he may be able to be talked into dumping it into the higher grade tanks, even though he faces a stiff fine if caught. These two factors seem to relate directly to a general "sleeziness" of stations.

The morals of the story: Give some thought to where you buy gas, and don't blame everything on the oil company.

---

Thanks for the info.....you made some good points.

BTW...did anyone in this thread "blame" anything at all on the oil companies?

Mikep

 

[Ken2]

A few years ago I was in a job where I bought about $500k worth of heavy fuel oil every five weeks. We hired an independent lab to gauge (measure) the fuel quantity and to run lab tests for quality. The lab guy I frequently worked with spoke of other assignments he'd had, sometimes working for Texaco when they bought gasoline from ARCO. This was a few years back when Texaco was still Texaco and ARCO was still ARCO. He said that the ARCO gas always tested below spec, Texaco adjusted the price they paid to ARCO, and reblended it up to spec before they sold it. Now that Chevron merged with Texaco and ARCO has been bought by BP, who knows what's happening...but ARCO is still the cheapest gasoline here, and gives me about 1 mpg less than even Safeway gasoline.


Ken

 

[TooManyWheels]

MikeP:

If I were to make that post again I would phrase the "blaming the oil companies" part slightly differently. My overall point is that there is more to fuel quality than just what happens at the refineries or in the pipelines. The process of getting it to the stations and through to your tank is a variable also. However, since most of these problems probably occur at unbranded stations, the producing company is probably never blamed anyway.

 

[mark pruett]

One thing to keep in mind is that US octane is measured via the Pump octane number, which is the average of the Research octane number (RON) and the Motor Octane number (MON).

They're similar tests, but not the same, so that any given 87 may be slightly different than any other 87 depending on how they came out on RON vs. MON.

I'd suspect this is the main reason different gas brands run a little different in individual cars.

Here's a link explaining RON vs. MON better than I did.

 

[mikep]

quote:

---

Originally posted by TooManyWheels:
MikeP:

If I were to make that post again I would phrase the "blaming the oil companies" part slightly differently. My overall point is that there is more to fuel quality than just what happens at the refineries or in the pipelines. The process of getting it to the stations and through to your tank is a variable also. However, since most of these problems probably occur at unbranded stations, the producing company is probably never blamed anyway.

---

Again, good point and I certainly agree with you.

Can you tell us anything about how the majors blend their fuel at the loading racks or depots? Isn't that where their "unique" additives and detergents are added? Any chance you could query your relatives in the biz to see if they know anything about the various brands and whether or not there is anything unique about their formulations once it reaches the pumps? Chevron w/Techron, Shell, Mobil and the detergent quality?

Mikep

 

[TooManyWheels]

MikeP:

I don't either relative will be able to tell me anything about formulation, but I will check.

On picking the fuel up at the depot - I was told, (or at least I understood) there are relatively few pysical connections to hook up to, maybe even just one, for all brands and grades. From the viewpoint of the relative, a trucker, the gas he picked up from a given terminal was "all the same", however he mentioned that he uses a different access code to access different brands. That indicates to me that there may very well be differing additives added automatically in the pumping process, depending on the code used.

I also remember getting the impression that not all brands were available from the same terminal. This would leave open the possibility that there could be differences in the refinery formulation that are more fundamental than adding or not adding additives.

I wish I could be more specific. I only see this individual periodically, and he isn't the best communicator, so I have to work hard for what info I get. If I ever learn anything to the contrary I will update the thread.

 

[MNgopher]

Already figured out where a good chunck of gas comes from here.

Four major refineries supply 90+% of the gasoline sold in this market.

One refinery and distribution terminal is on a dedicated pipeline and brings Mandan, ND, Tesoro refined gasoline to the BP/Amoco Terminal in the Twin Cities. BP/Amoco/Tesoro gasolines are all from that refinery here. Texaco and Kwik Trip tankers have also been seen commonly at this terminal.

Holiday gasoline is already low sulphur, and meets 2006 and beyond sulhpur regs. Only refined at one refinery in the area, Flint Hills Resources in Rosemount, MN.

Superamerica and Marathon gasolines are sourced from the Marathon Ashland refinery in Newport, MN. (Ashland owns Speedway Superamerica, along with Valvoline).

A small refinery in Superior, WI, also supplies gas to the market. Owned by Murphy Oil, they supply Murphy USA stations in Wal Mart parking lots and Spur stations.

Beyond that, its a crapshoot. General observations are occasional pinging on BP/Amoco 87 octane only. Best gas mileage of the bunch at +2% over the others. Superamerica/Marathon seems dirty and seems to leave extra soot in the tailpipe, as well as making the cats stink occasionally.

 

[DEWFPO]

All gasoline sold here in the US has to meet API specs (for a given region and octane rating), it can come from different crudes, and be better than the minimum spec but has to at least meet the minimum spec.

The biggest difference is in the additive package. Depending on the ownership of the terminals and who they sell to. The additives (such as Techron for Chevron) are added at the terminal when it it loaded into the tanker for delivery to a Chevron station.

That same terminal may sell Chevron API spec fuel to Stinky's gas station but if Stinky's is not a Chevron branded station, that load WILL NOT have the Techron added to it.

Chevron has people go out and sample fuel randomly and regularly to make sure that the Chevron fuel are indeed to spec with all the appropriate additives for the specific octane.

They are liable by law to make sure it is so.

DEWFPO

22 yr Chevron 'retiree'