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Old 09-06-2002, 12:08 PM
Whack-a-Mole Whack-a-Mole is offline
Join Date: Apr 2000
Location: Chicago, IL USA
Posts: 19,381
Is there a difference between different brands of gasoline?

Basically, is there any benefit to going to a Shell gas station vs. Amoco (or Chevron or Exxon or whatever it is where you live)?

Maybe it would be better to compare a Shell station to any no-name station you can think of since Amoco is likewise a biggie. Advertising would have me believe there is some benefit to using a particular company's gas. However, I suspect it all comes from the same dozen or whatever refineries and gas is gas and should be bought strictly on who has the best price at the pump on a given day.
Old 09-06-2002, 12:30 PM
Amfet Amfet is offline
Join Date: Apr 2002
Posts: 105
I don't know the straight dope on this...
but it was always my understanding that while the gasoline is comparable the storage/transportation conditions are not always so. Not sure if there are standards set by companies or not but I have gotten tanks of bad gasoline before. Once after filling up at a Shell my bike would not start. Had it hauled to the shop they said there was water in the gas. According to the bike shop it is a pretty common thing especially in the early spring time (Chicago area) and is a symptom of poor or dammaged storage systems. Since motorcycles tend to have smaller more sensetive engines than cars do the effects of bad gas are more aparant. You can run a tank of contaminated gasoline through a larger vehicle and barely notice it. FWIW I have since filled up at a different Shell location and have had no problems. I guess what I'm trying to say is gas can be different from station to station but it depends upon your type of vehicle if you're gonna notice it or not..
Old 09-06-2002, 02:43 PM
Lure Lure is offline
Join Date: Apr 2002
Posts: 430
The only difference-this from a "Modern Marvels"segment is the additives different companies use.They probably-this IMO-all use the same basic types of additives-just in differing formulations.

Another did you know is-ALL the oil companies using the Texas big inch,as well as it's tributaries,use it on a one gallon in,one gallon out basis.This means that a Shell refinery in the NE tapping the pipeline is not necessarily getting Shell oil.

Add to that the practice of tanker trucks dropping off their leftover gas at other branded gas stations,so they return to the refinery empty,with all that load sold.

And mentioned previously some local gas stations'holding tanks may not be as clean as others.

Buy the cheapest is my motto,sometimes you're even getting the most expensive for that price.
Old 09-06-2002, 05:52 PM
David Simmons David Simmons is offline
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Join Date: Nov 2001
Posts: 12,684
Originally posted by Lure

Another did you know is-ALL the oil companies using the Texas big inch,as well as it's tributaries,use it on a one gallon in,one gallon out basis.This means that a Shell refinery in the NE tapping the pipeline is not necessarily getting Shell oil.
I'm not so sure about this. I think I remember reading that pipeline operators have the equivalent of an "end of message" signal. When the batch from one company is at an end, a dye is injected into the flud and the next company's stuff is then started. I'm don't think there is mixing of fluid from one batch to another in the line.

Or was that all in a dream?
Old 09-07-2002, 08:44 PM
Wonko The Sane Wonko The Sane is offline
Join Date: Jul 1999
Location: Outside the Asylum.
Posts: 2,115
The gasoline at different stations is made to different standards. Sometimes, they are made at a refinery owned by a different company (Tosco Oil is one company that does this*). I would assume that the gasoline is probably fine unless you buy "Johnny Trainer's mystery gasoliney fluid of doom". The Crude oil from different parts of the world has different properties, so one crude may give more gasoline, and less of other things, or vice versa.

*I used to work at one of their refineries, and they made gasoline for Exxon, Circle K, and other places. Each gasoline going out had certain criterea to meet. Even different parts of the same state can have different "blends" to meet EPA regulations.
Old 09-08-2002, 01:02 AM
mangeorge mangeorge is offline
Join Date: Mar 1999
Location: Berkeley, CA
Posts: 14,089
David Simmons's "end of message signal", IIRC, is called a "pig". It's a radioactive substance injected into the pipeline. The valving is automatic, and reads this marker.
Old 09-08-2002, 02:06 AM
octothorpe octothorpe is offline
Join Date: Aug 2001
Location: Lost Wages, NV
Posts: 229
Unless the terminology has changed, a pig is a device (similar to a torpedo) sent down a portion of the pipeline to clean the pipeline.

As to the color markings, they usually are used to differentiate the octane content of the gasoline. The common markings were, at one time, red, blue & white signifying regular, premium & unleaded respectively. With the advent of various grades of unleaded (including gasohol) and the demise of leaded gasolines, these colors have probably been reclassified to cover the unleaded grades. These same colors are generally used on the covers or caps of the storage tanks at gas stations to facilitate the unloading of the tankers. Next time you stop for gas, look for the lids, chances are, they are colored. Knowing which color corresponds to a particular grade of gas will allow you to determine which storage tank is used for which grade.

As to water in the gas, this is something that is easy for a service station to determine. Although new tank designs allow for electronic monitoring of the levels in the storage tanks, it should still be a policy of any station owner to 'stake' his tanks. This is a simple operation involving a long pole with english or metric graduations. You read the pole just as you would the dipstick while checking oil. Knowing the volume of the tank and using your handy conversion chart, you determine the amount of fuel remaining in the tank. To determine whether water is present, a 'water finding' paste is spread over the first six inches or so. The presence of water will cause the paste to change colors (basically like litmus paper). If you purchase fuel that contains water, the best bet is to no longer give that particular station your custom as they obviously don't care enough to provide a quality product.

Finally, in years past, Standard (and all subsidiaries) would not allow its gasoline to be sold by non-Standard branded stations. How it managed to control this i can't readily attest to on all accounts, but i can say that Standard had its own tanks at the terminals of the pipelines. Basically, when Standard sent a load of fuel through the pipeline, it notified its terminal and 'marked' the fuel with a particular dye. Thus, the terminal knew to look for it and it was diverted to the Standard tanks. From there, it was easy to control which tankers picked it up.

Old 09-08-2002, 02:45 AM
Tuckerfan Tuckerfan is offline
Join Date: Jan 2001
Location: Gallatin, TN
Posts: 21,676
Wonko, funny you should mention them. I used to work for Circle K (which is owned by Tosco) and the tankers that showed up at the stores all said Dupree.

I think that the major difference in brands depends upon the gas station owner more than it does the company that produces them. (i.e. how well they maintain the place and tanks). I've gotten gas at lots of different places and the only time that I noticed a difference was when I stopped at a Shell station and my car ran horribly until I got that tank out. Was it really Shell gas? Dunno. Did I ever stop at that station again? Nope.
***Don't ask me, I don't post here any more, and I'm probably not even reading this now.***
Old 09-08-2002, 06:32 AM
Mort Furd Mort Furd is offline
Join Date: Apr 2001
Location: An American in Germany
Posts: 1,432
My experience is that fuel from different gas stations is different. My father tells me that gasoline from one certain gas station where he lives is better than gas from other stations when it gets cold. Apparently, the gas station in question gets gasoline with a different blending of additives that causes it to do better in cold weather. I also notice that diesel fuel from Aral (here in Germany) does better (mileage wise) than fuel from DEA in cold weather - and that the DEA fuel does better (mileage wise) than the Aral fuel in warm weather.


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