my buddy sent me an email about which gas stations get their oil from *******s and which ones dont. suppposedly thats why arco is so cheap, that and they cut costs other ways too, like accepting only cash and charging for debit use, and its prepay only, and the ampm store helps bring profits to cut the costs of the fuel. but you always hear people talking about it being watered down or "my truck only likes chevron" i think thats a bunch of bull ya know? i think gas is gas and it all goes through the same refining process. that advertisement shell has with the picture of the gunky valve looks like the biggest crock of bull i've ever seen. i dont buy it one bit. what are all your opinions on gasoline brands?

 

One thing I know. Gas station owners make very very little profit from fuel. Only a couple cents a gallon. That is the reason they have stores attached to them. That is where they make the money.

As for the quality, all I can say is that some gas works in my truck and others don't work as well. Dieseling can be a problem for me with some kinds of gas. I currently use the cheapest gas station in town and have not had the problem since.

 

I use BP. My vehicles get the best mileage as compared to other brands around here.

 

wow they bleeped out the nonpolitically correct term for an arabian person

 

There was a thread going on in another forum here, maybe the general automotive, anyway someone also listed which gas stations are owned by who and it helps me avoid buying gas from creeps like Chaves who owns all the Citgo stations.

Opinions are like...well you know, any everybody has one. You should try to back up your ideas with some kind of proof or reseach. I know what I've experienced and that's all. My Alfa didn't run worth a darn on the gas from Costco. When I put Shell in it, it runs way better and gets up near 35 mpg. My Ford doen't seem to care one bit what gas is in it, it runs strong all the time.

 

What the sign says by the street isn't the same as what should be in the tank. I used to haul what ever was cheapest into Shell stations. The customers sure let us know when we did that!

 

Yes, it does go thru all the same refining process....but they all have their own "secret additives". You can take a small amount of fuel to the lab and you can tell which brand it is by its "DNA". If you had a contract to only purchase and retail Shell fuel for example, Shell inspectors could come to your stations and test your fuel. Non-Shell fuel and you were busted! Fines and loss of contract.

As to the valve story...maybe Shell has more detergents or a special formulated detergent. They won't say to much due to competition.

 

Don't know about your area, but around here there's only two tank farms, everybody gets there fuel from one of them.... Casey's General Store is the only station around here that hauls their own oil with the exception of a few of the rural stations that have a bulk plant and service the area farmers......

I suppose life is different in the big city.....??????

 

I work on an Air Force base. A while back I was filling up and there was this fella replacing the fuel filters in all the pumps. The filter looks just like the oil filters that go on our trucks. Anyway, I asked him about how often he changes them and a whole buncha other stuff. He says that there is a maintenance schedule for the pumps but almost nobody changes the filters like they should except for the Army and Air Force bases. He said if he was gonna buy gas he'd get it from the bases. He said most of the service stations almost never replaced the filters.

I was talking to another guy the other day. I've known him for a number of years but not real well. We were drinking beer and got to talking about what we did and it turns out that he works for the state testing fuels at service stations. When I told him where I buy my gas (cheapest place in town) he said that the guy there was mixing his own mid grade octane fuel by adding ethanol to the low octane stuff. This guy saw that as cheating but I guess that's legal becaue the place is still in business. It didn't matter to me because I buy the low octane stuff anyway. So I guess I'm being long winded with something that goes to show that eventhough they all get the same gas, there are ways of looking it that gas isn't always the same.

 

It varies by region. Anyone running a blown or high compression engine can vouche for the fact that there are differences. Up in Virginia Citgo gas did the best out of the 3 brands I ran. Here in Georgia Citgo runs a close 2nd to Chevron and BP. Shell is horrible in my truck and causes it to ping at WOT just before shifts. Murphy (Walmart) gas was the same way, caused ping at WOT just before shifting. Recently they've either changed formulation or suppliers because now I'm getting some of my best results from their gas. None of this is speculation... its based on data logging in a new truck watching the knock sensor signals. Now, obviously results vary by region, and sometimes by vehicle. Shell may be great in another region but its lously here. BP may be lousy in another region but its great here.

Now, what does this mean for an older truck with a distributor and a somewhat stock engine (ie, not a high compression engine) running 87 octane? (Disclaimer: my tests were with premium because the blower requires it) Well, with better gas you might be able to run an extra degree of timing at 87 octane. It won't make a huge difference in power or mileage but it will make a little difference, and its free.

 

It also depends on the time of year also. March is the change over from winter blend to summer blend. November is when they switch from summer blend to winter blend. Terminals let there tanks get as low as possible before they get in the next shipment. They try to co-ordinate this so there isn't too much of a carry over of one product to another and waters down the blend. I heard of a story of stations getting their summer blend a little too early in Arizona. It got cold for a few days, below freezing and vehicles didn't run right. When it warmed up they ran fine.
Yes, gas does differ in regions, vehicles, time of year, stations and between drivers.

 

My grandpa was the operations manager for the Flying J refinery(Big West Oil) here in Utah. He worked there for over 40 years before he retired, so he knows a bit about the production of automotive grade fuel. We have had multiple discussions about this issue. All of these "special, proprietary additives" that companies market are either EXACTLY the same or vary very little. There are specific guidelines that they must follow regarding these additives and they must not deviate from these guidelines. Chemically, the gasolines that are supplied to these stations are nearly identical. The minor differences can be attributed to temperature, humidity, etc. Unlike we are led to believe, there are NOT any "special" trade-secret recipes out there because of the strict regulations put on ALL refineries regarding the production of gasoline.

Like mentioned above, SOME stations have contracts with certain suppliers, but other stations get it from whoever offers the best rate at the time. Specifically, the non-branded stations are part of this grouping. Of course a Shell station will distribute Shell, Chevron sells Chevron, Tesoro sells Tesoro, etc. However, in a 3 month period, I saw both a Flying J truck AND a Chevron truck supplying gas to one of the local Sam's Club pumps. So you may thing you are getting one brand of gas all of the time when, in actuality, you have been running 2 or more brands through your tank. Also, the tanks the gasoline is stored in can influence differences as well. This can be caused by excess sediment in older tanks as well as degradation of the tank itself. Older stations, unless recently upgraded, could be using tanks older than your car. All tanks storing gasoline, over time, will degrade. The alloys used in newer tanks are much more resistant to this.

If none of this was enough, last year one of the local stations took unlabeled gasoline to an independant laboratory and had them tested. None of them varied greatly from one another.

One last thing. It was mentioned that gasoline varies depending on the time of year. Gas made in July is different than that made in January This is even more so in climates like Utah where there is a drastic change in temperatures. It is produced this way because gasoline, though somewhat stable, is greatly affected by temperature differences. It is made this way to aid in starting in cold weather and reduce the rate of evaporation in hot. Stations tend to run through what they have on hand before they get more. If they are sitting on a large stock of "cold temp" gas, then the weather warms up, it is not uncommon to see gas mileage drop due to the reaction to the warmer temps.

 

around my house there aren't really any gas stations close, so you pretty much drive to the one in whatever area you are going to at the time, or whatever one is closest, which for me is like ten miles. I guess that isn't so far, but it sucks when you are sitting on empty

 

why would you want to advance your timing a degree or two based on octane? the truck needs to ignite at its optimum moment no matter what fuel you use so if its not knocking i dont understand

 

For the same reason ECMs on modern vehicles advance timing when they detect no knock: it results in slightly more power and better fuel economy. The optimum is to have it advanced as it can go without pinging.

The higher the octane the slower the flame front of the fuel is and the higher the flash point so you can advance ignition more. Why advance ignition? Because when ignited the air/fuel mixture expands rapidly. Because the expansion of the burning mixture happens before TDC at the same time the piston is on its way up, advancing timing increases the effective compression ratio of the engine.