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View Full Version : Arco, or Shell?



aostling
03-10-2009, 08:19 PM
I just saw a TV ad for Shell gasoline, which now has an additive for "nitrogen enriched cleaning power." Me, I'll continue to buy the cheapest gas I can find. Usually, that's Arco (but not always).

Is there any difference between petrol brands?

JCHannum
03-10-2009, 08:29 PM
Around here, most pull from the same terminal. The driver dumps a bucket of magic elixir in when fillling the tanker.

I wonder just what nitrogen adds to the mix that gives cleaning power, and how the bucket of nitrogen is added.

loose nut
03-10-2009, 09:11 PM
Gas is just a specific "cut" of naphtha, whoever makes it.

The difference is in the quality (purity, amount of gunk thats in it, octane etc). The main difference is the additives. Some have octane boosters, cleaner for injectors and such. Some of the small independents that buy on the spot market will sell whatever they can get cheap.

saltmine
03-10-2009, 10:12 PM
Gasoline comes in bulk, three "grades" unleaded regular, regular, and Premium.
This rating is based on their "motor octane" from lab tests. When they get ready to ship out a tanker full of fuel, the guy at the distribution center (bulk plant) dumps in whatever brand's particular blend of additives and boosters that make that brand unique into the outbound truck. On generic gasoline, like the load going to Wal-Mart or some "no-name" gas station, they take whatever the last tanker load had for an additive package, and call it good.
Like Loose Nut said, whatever they can get cheap. The worst additive you can get these days is ethanol (alcohol). Federal law specifies that it has to be marked "Gasohol" if it's 10% ethanol by volume. Of course, the stations are not required to mark it if it's more than 10%, but they have to label the pump dispensing it as "containing ethanol". Some stations used to dump as much as 60% ethanol into their storage tanks, when ethanol was cheaper than gasoline...Now, it's more per gallon, so you don't see ethanol added much, unless it's mandated for cleaner operation in colder or emission sensitive areas. If the pump states "This fuel contains ethanol" count on a 10% reduction in fuel economy.