As opposed to grades, I mean.
If I fill up with Shell is that any better or worse than Esso? Or Petro Canada? I know that Husky adds ethenol to their gas - does that affect engine wear, or is it purely an emmission thing?
I’m told the gas is pretty much the same, but that different brands add different additives. A mechanic once recommended alternating between the major brands. Sort of a healthy diet for your car.
Pretty much all gas contains ethanol now, or has a disclaimer that it may in fact contain up to 10% ethanol.
Gasoline is pretty much the same, although the marketing geniuses would like you to believe otherwise.
Mr. Gas and other independents buy their gas from whatever major brand-name refinery they can source it, at the best price du jour.
No noteworthy difference in gases.
Some difference in additives.
Google “top tier gasoline” and “techron” for a start.
I worked on a software program to do scheduling for a pipeline company. This company had pipelines in the western US in which anyone could ship (any grade of) gasoline or diesel fuels.
The simple model was, Company A would deliver (usually by tanker trucks) X number of gallons of product at Station A. The pipeline company would pump it to Station Z where Company A could then pick it up (in tanker trucks again).
Of course, things are never quite so simple. The pipeline was actually a network rather than a single pipeline, etc.
But the feature apropos to this question was this: Companies could designate their product “Common Code” and get a cheaper shipping rate. By designating this, they were saying, "I’m giving you (say) 87 octane unleaded gasoline. I want to pick up 87 octane unleaded at Station Z – but it doesn’t have to be the same product I gave you at Station A. Any 87 octane unleaded will do.
Most companies DID designate their product Common Code. So it was very common for Chevron to pick up product that Arco refined, etc.
And in a very odd twist, companies were occasionally allowed to pick up their product at the destination station **before **actually delivering it to the input station!
The bottom line: it’s very likely that the gas you buy at one station was actually refined by a different company. However, note that “additives” were usually added to the gasoline after it had been delivered, so there is some difference between brands – but not as much as you might think.
J.
I’ve heard what jharvey963 said - that they basically all dump their gasoline into a pipeline down in Texas, and pump it up to the northeast. What goes in is definitely not the gasoline that the company takes out, as it just all mixes together. It’s the additives that affect things, though how much so I am not sure.
Our resident master automotive technicians will surely be by as soon as they see this thread to disagree. Rick, in particular, is fussy about Chevron’s Techron.
Around here, everyone blends in some amount ethanol for smog control purposes - this time of year, they run about 10-15% ethanol.
I only have to add the minor detail that some cars run like crap on certain “brands” of gas. I had a number of older cars that spit and sputtered whenever they were fed arco or astro (not imediately, but soon thereafter). I pretty much stick with certain brands for my new car, dont want to risk a tank full of gas and water.
Fry
Yes I am fussy about the gas I put in my car. Thanks for noticing (and saving me the search) 
Are the base stocks similar between brands? sure. Are the additive packages different? You bet. The additives are what make or break a gasoline.
Here in Minnesota, ALL the gasoline sold in ALL the stations comes from 3 pipelines into the state. So it’s all the same at that point.
After that, each company can add their own special additives to make the gas different. And some stations may keep their tanks cleaner, or sell gas faster so it spends less time in the underground tank.
You can decide if you think any of that makes the brands ‘different’ enough for you to pay more or make efforts to always buy a particular brand.
Hmm. Have you tried those “bad” brands in other regions and get the same results?
I have no idea what your personal situation is like, but I have been living in the same apartment for 12 years now. I, too, sometimes experience a noticable difference in quality amongst the major brands. (I seem to be doing ok by Shell.)
But it could also be the individual stations that you are using have old tanks that have sediment in them, or some other site specific issue.
Actually, there is not that much ‘mixing’ happening in the pipe it self. Diesel can go in after gasoline and they know pretty good when all the gas has arrived and can switch the line to a different tank. The loss is very small. If the supplier wanted their particular product, they can do it, it just costs a bit more. All kinds of product was pumped through the ‘Explorer’ (big line that runs through Tulsa more or less N/S) and the ‘OMR’ ( Okla. to West Memphis) etc. that I used to patrol.
A station with good clean tanks, never using from a tank that was filled that day and staying with one grade in that particular vehicle has allowed me to avoid bad fuel problems in my wheels for a long time now. When out of my area, I stick with a few major brands and I never use the little independents, they may be just fine, as I do not know them or how fresh their fuel is.
YMMV
!Is these some sort of movable plug between the different liquids or do they just not mix that much? I find that surprising.
(Warning: Science content… )
No, there is no movable plug. One of the requirements on our pipeline scheduling system was to always ensure that the product was being pumped through the pipe fast enough to create a “turbulent flow” situation, rather than a “laminar flow” situation. In turbulent flow, the product is actually moving around in the pipe a lot (in relation to its position in the pipe). Paradoxically, this prevents wholesale mixing of large parts of the batches.
In laminar flow, the product flows smoothly through the pipe and doesn’t change it’s position in relation to its position in the pipe.
In turbulent flow, you get a little mixing at the boundary of 2 different products, but not much. In laminar flow, however, the product is moving smoothly through the pipe, but the pipe walls exert some friction on the product touching the pipe wall, slowing it somewhat. The product touching the wall exerts some friction on the product right next to it, and so on. So in laminar flow, the product at the center of the pipe is actually moving faster than the product at the edge, producing a large “plug” of product that mixes into the batch in front of it. Hence: laminar flow = bad. Turbulent flow = good.
J.
So, if the fuel is essentially the same, but the additives are different, how does one determine which gas to purchase?
Is there one brand that’s better than the others? Do experts recommend a particular brand? Just to complecate things, I’m in Canada - does anyone know which Canadian brands of gas are considered “best”?
Look at the big signs outside the stations, which give the price. Pick the one that’s lowest.
:rolleyes: :smack:
::: Sigh:::
Delivered where? To the tank beneath the last consumer pump that fills a typical car? If so, who adds it? The tanker driver, the filling station or the pump to the car? Or did you mean at an earlier distribution point?
Distribution point