Gasoline, discount vs name brand, quality the same?

In My Humble Opinion
21

Do you have a cite for additive quantity being associated with octane?

Around here, most stations are Top Tier, and here’s what Consumer Reports says about them:

As for a relationship between price and additive package, I think you can see it in areas where there are run-down no-brand stations. Around here, the cheapest is usually Costco (if a member) and, otherwise, Conoco. Both are Top Tier.

I think there is more of a relationship between price and station appearance than between price and the additive package.

22

You’re correct to be skeptical about that statement I made. A quick googling shows that while that may have once been true, it isn’t now, most specifically when looking at brands that qualify for the Top Tier rating.

From Edmunds…

Years ago, premium gas contained more detergents and other additives to stop carbon deposits. But experts say that now, because of government regulations aimed at cutting emissions, most major brands of gasoline have plenty of additives in all grades to both protect engines and cut pollution.

23

I had the fortune (misfortune?) of working as an engineer for a large oil company in their pipeline department for a while when I was younger. The company pipelined gasoline into various markets either directly from a refinery or sometimes from a barge terminal or port. The place where a pipeline ended was called a truck terminal.

At these terminals would be a few gigantic above ground tanks (like 100,000-250,000 bbls) of gasoline, a big ethanol tank, a ‘rack’ (used to fill the tanker trucks), pipes, pumps, and a few smaller tanks of various chemicals, dyes, other additives.

There would typically on be one truck terminal in a geographical region, I was never aware of any competing pipelines coming into that region, and that terminal supplied fuel to all the gas stations in that area. I suppose it’s possible there could have been some independent gas stations on the fringes that trucked it in from somewhere else, but they would have been the exception.

There was typically a set of smaller tanks of chemicals close to the rack where the trucks were loaded. The trucker would pull to the rack (and there would be three or four lanes at the rack) and there was a computer where they would enter their order. Then a computer/PLC would activate various valves and pumps depending on which product was entered on the order. The additives, ethanol, and dye were all added to the fuel while the truck was being filled.

So for example, if a Shell truck was being filled next to a Chevron truck, they would both be getting their gasoline from the same giant tank (all refined by a third oil company), but they’re each getting their own ‘special’ blend of additives. Some of the additive tanks did have branded logos on them… Shell had their own, Chevron had their own, Marathon had their own, etc. But the the ethanol and gasoline all came from the same source. I couldn’t begin to tell you the difference between those additives, or whether they made any real difference to the consumer.

I do remember sometimes smaller no name trucks (I think they were called “jobbers”) and they often did not get any additives (or very few).

I can also say that the quality of underground storage at individual gas stations varied widely. Some older stations had leaky steel tanks. Some stations had issues with water intrusion into their gas. Some stations had accidentally contaminated their tanks at various points in time. Who knows what the history of a particular gas station’s tanks has been? You just have to take your chances unless you have some specific knowledge.

I would think there is minimal difference in ‘name-brand’ gas and other gas… Its probably the same gas, with slightly different additives. The only thing I ever avoid is buying gas while the tanker truck is actively filling the tanks at the station (I have no idea if this a valid concern, but it makes sense to me).

ETA - I should clarify, there were separate giant tanks for the various octanes of gasoline. The octane was determined at the refinery. and delivered back to back by the same pipeline, and directed to specific tanks at the truck terminal by a valve manifold.

24

My money, if I had to place a bet, would be on “c.”

25

@pyromyte two posts up …
Thank you for coming in and sharing the insider version of the facts. IMO that’s the best part about hanging out around here.

A question if I may ref this:

Is your concern fire hazard from fumes from open fill ports, fuel temperature, stirred up sludge in the fuel body caused by the turbulence of the filling process that would / should settle out later, or something else I haven’t thought of?

26

My concern is that if there is anything settled in the tank (like water, sediment, etc) it will be sloshed by the incoming fuel and then be able to be sucked up by the pump pulling it to the dispenser. There is another filter inside the dispenser which should catch things assuming the station operators change them frequently enough. Its a small concern and I avoid it if possible, nothing to lose sleep over. :slight_smile:

27

Makes sense. In any tank design there’s always the tradeoff of “how close to the bottom do you place the outflow offtake?” Especially in underground fuel tanks where water intrusion is inevitable and settles to the bottom in addition to any foreign matter.

The effective capacity of a tank is only the part above the offtake, but avoiding sending the inevitable debris downstream matters too. Not my area of expertise that’s for sure.


Now that I’ve cornered an expert :slight_smile: …

I’ve got a separate comment / question to the above:
I am a bit surprised that the additive package is added right at the tanker truck filling point. Makes total sense logistically, but that raises questions about how thoroughly the various additives get mixed into the fuel body.

If they are simply dumped in the tank first as a bulk slug you get some mixing as the fuel is poured in on top, but not a huge amount, and especially not late in the filling process. If you try to meter the additives in at the appropriate ratio during the bulk fuel loading, that seems to demand some pretty high precision metering valves as the percentages involves are (AFAIK) pretty darn small vs. the bulk fuel.

How does this work? Roughly what percentage do the additives represent within the completed product? Presumably the specific gravity of the various additives isn’t too different from that of bulk fuel. Is subsequent stratification a concern at any stage in the process? Or does it just not matter because the additives burn close enough to the way the bulk fuel does that even an very, very additive-rich or -poor blob of fuel is close enough for combustion purpose, and meanwhile the additives’ function is more a matter of their chronic presence within the fuel system and fuel / exhaust stream than it is matter of their contribution to each individual firing of the cylinders?

Any overall comments down this general direction you’d care to share? Thanks in advance!

28

I usually get my gas at the Murphy Stop and the car runs pretty good. They even brew up their own gasohol from locally grown corn.

29

You might find some of the discussion in this thread interesting. Specifically:

Virtually all additives that go into any fuel, as specified by the retailer, is done at the fuel terminal when the tanker is loaded. I used to haul fuels. It is interesting to swipe a card that lays out the specs for the end retailer, then watch various lights go on with different tanks as they inject additive into the stream being loaded in to the truck tanker.

What I did not expect was that some smaller retailers dump the additive pack directly into their underground tank just before the truck refills it. Sounds like that might be a practice specific to some of the unaffiliated, single location owners.

Also, it appears that Costco has an on-site system that is loaded by a separate delivery from the actual fuel truck. That system then meters the additives directly into the undersround tank.

I’ve seen a Brenntag Pacific or a Quality Carriers truck at the local Costco that wasn’t placarded for gas - they have an on-site injection setup to meter and dispense their additive which I believe is a Lubrizol product.

30

The additives are injected directly into the fuel stream being loaded onto the truck. I don’t know much about how they were metered, but It didn’t look ‘precision’. But based on where it was injected (just upstream of the flexible fill hose), I would think the mixing was pretty darn good.

Aside from ethanol, I am not sure, but based solely on how tiny the additive tanks and piping are compared to the giant gasoline tanks and piping, the additives had to be miniscule amount… like maybe a few gallons added to a 11,000 gallon tanker truck. I am just guessing. Googles says it could be in the PPM for some additives, up to a percentage point, but I am guessing most are more on the PPM side.

I think the additives stay pretty-well mixed in the gasoline, Its like adding food coloring to water, once it’s mixed in there, its in there. Maybe if fuel sits for a LONG time, maybe it could do something weird (not much of a chemist), but I’ve never heard of it.

On the other hand, gasoline/ethanol blends (which is the majority of gasolines sold nowadays) can do funky things if water gets in the storage tanks. Alcohol mixes with water better than it mixes with gas. And if enough water gets in the underground tanks, there could be a nasty, cloudy, corrosive water/alcohol layer near the bottom of the tank, and slightly reduced octane layer of gasoline in the upper portion of the tank. Neither of which are ideal.

31

Unless things have changed drastically in the last 20 years, @pyromyte is pretty spot on. Everyone gets the same gas, additives are the only difference.

I used to own four gas stations/truck stops and I could buy any branded name gasoline/diesel fuel I wanted. However, I couldn’t advertise it as the brand name. AFAIK, there is no generic gasoline. I usually bought Standard/Chevron/Amoco for my stations. Funnily enough, one of my places had an Amoco station across the street.

I will push back a bit about gas being a low profit margin everywhere. Location matters. My store were split between two cities 75 miles apart. The smaller city, I regularly made 25¢ + a gallon. The larger city varied a lot, from pennies to 10¢.

As for water in the tanks, unless you are trying to fuck over people, it just not a problem. In the old days, we had to measure the amount of gas in each 15,000 gallon tank by putting a 12 foot pole in each tank every morning. The bottom of the stick would be covered with a paste that changed colors if water was detected.

When I had modern tanks installed, they had water sensors as part of the tank and would shut down if water was detected. If you did have water for some reason, it was simple to get taken care of. Any tank supply/repair place has trucks that they will send over to suck the water from the bottom of the tank.

32

The presence and amount of additives are different, so everyone doesn’t get the same gas.

33

That was an interesting discussion, thank you. And included a true believer filled with STP woo. Fun.

One of the posts in that discussion contained a further cite to:

which is an article by a small consultancy / self-appointed expert(s) on gasoline distribution. He might be a wacko, but he doesn’t smell that way. Some interesting info. The pdf itself contains no date, but elsewhere his website says it was published in 2016. So fresh enough to be relevant to current industry practice.

Offered for our consideration, not as gospel.

34

I don’t want to put words in your mouth here but it seems you are concluding that octane matters for quality. Octane matters, but it is not an indication of quality.

35

Yeah. Octane rating matters for octane rating and only octane rating.

Might there be at some times and some places a marketing push to make higher octane fuels seem better in other ways? Sure. Actually better? Maybe.

But the only thing higher octane fuels are for sure is … higher octane.

36

We’re probably using the term “quality” differently. Using the wrong octane for your engine is using poor quality gas. That is, “quality” is relative to the requirements of a specific usage.

Going back to my first post:

The closer the gas’s octane rating is to 87, the better quality it is for my car. Too low is not good for the engine; too high is paying extra for no improvement.

37

That’s in the very first sentence of my post.

38

Great info shared thus far thanks all.

In a nutshell imo

All things being equal (atbe) all gasoline delivered to the truck terminal is the same.

What’s not equally the same is the gasoline each of us buys at the pump.

39

I am reminded of something someone told me once and I am dubious.

So gas stations will typically have three octane levels available. I was told that when you get the middle level, you are getting a mix of the lower level and the top one. There isn’t a storage tank for the mid grade. True?

40

As described upthread and in a few of the cited cites, both methods are used. Some stations have 3 tanks for three grades, some stations have two tanks for low- and high- then blend them at the pump to get mid-range octane.

For stations with 3 tanks, the truck delivers all 3 grades. But the fuel depot where the truck was filled created that mid-grade on the spot by blending their supply of low- and high- right then, just a couple hours before it arrived at your station.