Gas station mileage

[K85 Octane]

Daily commuter. 74 mile round trip, every day, very consistent with about 70 miles on highway, similar traffic. I'm sure there's other trips for groceries etc. This car "requires" 91 octane.

39,310 miles before test

ARCO 89 octane empty at 39,884. Used 21.197 gallons to go 574 miles. 27.08 mpg

COSTCO 91 octane empty at 40,498. Used 21.277 gallons to go 614 miles. 28.86 mpg

CHEVRON 89 octane empty at 41,014. Used 19.80 gallons to go 516 miles. 26.06 mpg

I wouldn't mind giving Chevron another try to make sure traffic/fast food stops were equal. I really believe they were already though.

Price comparison. Because Costco doesn't advertise, I can't get an equal TODAY price. I will list what I paid and when.

3/30 ARCO = (I don't have this receipt, I filled up again on 4/23) $85.04 for 19.80 gallons

4/7 Costco = $97.49 for $21.197 gallons

4/16 Chevron = $112.75 for 21.277 gallons

FYI

 

[K85 Octane]

$.158 cents a mile for ARCO and Costco
Costco being better for my 91 octane car
Interesting

 

[imiceman44]

$.158 cents a mile for ARCO and Costco
Costco being better for my 91 octane car
Interesting

Costco does have better gas, I know because I know personally the manager for my Costco gas station and we talk all the time.
And I have seen it and so did anyone who listened to me and wanted to check.
And in general, they are the cheapest in my area

 

[dyeager535]

I once drove out of my way to get non-ethanol fuel to test if the mileage gain was worth it. Over a few hundred miles I saw no difference. FWIW I religiously (zealously?) calculate MPG every tank.

Since 2004, 140k on one car before selling, 110k on present car, almost exclusively Arco gas, not a problem one, except when the car sat a year...it needed new gas mixed in, octane had clearly dropped, and the newer high compression engines REALLY don't like that. Truck in various iterations has always had Arco gas too. I don't have a Costco nearby but if I did, and the lines weren't ridiculously long, I'd probably go there.

If the car drinks it, I'd buy off price. Me being cheap, but I can't pay $.20-.40 more per gallon for the gas across the street if the cars apparently can't tell the difference. I can't simulate driving conditions good enough between tanks to think that even a 2-3MPG difference (in a vehicle that will do 40MPG+) is attributable to the gas vs. all the other factors I can't control.

 

[Blue85]

That's what I was going to say. A single tank doesn't give a very good picture of actual MPG. Even on the same route, there are differences in the wind, traffic patterns and where exactly "tank full" happens.

As for E10 vs Ethanol free, unless it's a flex fuel car with the fuel composition sensor, it takes a while for the fuel trims to relearn. It would be more fair to disconnect the battery between fuel types, or reset trims with a scan tool.

 

[imiceman44]

That's what I was going to say. A single tank doesn't give a very good picture of actual MPG. Even on the same route, there are differences in the wind, traffic patterns and where exactly "tank full" happens.

As for E10 vs Ethanol free, unless it's a flex fuel car with the fuel composition sensor, it takes a while for the fuel trims to relearn. It would be more fair to disconnect the battery between fuel types, or reset trims with a scan tool.

I don't do 1 tank full calculation for anything, I do keep the numbers but in the end I only rely on results of at least 10 tank full.
The reason is that a lot of factors affect the mileage but also not every time you can guarantee that you filled up to the same level of full, by adding it up you divide that difference by 10 so it becomes negligible.
I also did the same with diesel in my big rigs and those are more sensitive to quality of fuel, when you're pulling 80k lbs, the difference becomes more obvious.

As for non ethanol fuel, I did a trip to the east coast and as I got to states in the Midwest that carry it I only ran non ethanol and I did see a consistent 3mpg gain in range on a 35mpg car.
The cost was just under mileage gain so it wasn't enough to justify, but the te longer range meant fewer stops and the biggest reason for non ethanol is the lack of water condensation in the tank and the damage to older fuel lines, and of course small engines that don't do well with ethanol fuel

 

[Blue85]

I've run a bunch of grades through flex-fuel cars and the $/mile always comes out pretty close, which is pretty much how they intentionally price it. Years ago, E85 was locked at $1 less than E10, so the better buy depended on the price of gas. Then in 2014 gas dropped under $2/gal and they revised that model! You know what I was putting in the FF cars at that point:


I do buy Ethanol-free 91 Octane over E10 91 Octane here, because they are the same price. Plus, I always keep gas cans full of Ethanol-free for all of the small engine stuff and that's only offered in 91 (for the herds of snowmobiles and SxS). I have no issue putting E10 in any FI car.

 

[centexk5]

Daily commuter. 74 mile round trip, every day, very consistent with about 70 miles on highway, similar traffic. I'm sure there's other trips for groceries etc. This car "requires" 91 octane.

39,310 miles before test

ARCO 89 octane empty at 39,884. Used 21.197 gallons to go 574 miles. 27.08 mpg

COSTCO 91 octane empty at 40,498. Used 21.277 gallons to go 614 miles. 28.86 mpg

CHEVRON 89 octane empty at 41,014. Used 19.80 gallons to go 516 miles. 26.06 mpg

I wouldn't mind giving Chevron another try to make sure traffic/fast food stops were equal. I really believe they were already though.

Price comparison. Because Costco doesn't advertise, I can't get an equal TODAY price. I will list what I paid and when.

3/30 ARCO = (I don't have this receipt, I filled up again on 4/23) $85.04 for 19.80 gallons

4/7 Costco = $97.49 for $21.197 gallons

4/16 Chevron = $112.75 for 21.277 gallons

FYI

Was bored and whipped up a quick cost table.

Brand	MPG	Gal/Yr @15k annual miles	Cost/Gal	Total Annual Cost
Arco 89	27.08​	553.91​	$4.29​	$2,376.29​
Costco 91	28.86​	519.75​	$4.59​	$2,385.65​
Chevron 89	26.06​	575.59​	$5.29​	$3,044.90​

	Cost Difference
Arco to Costco	-$9.36​
Arco to Chevron	-$668.60​
Costco to Chevron	-$659.24​

 

[K85 Octane]

While the math is solid the "average" is missing because I only did it once. The motivation behind even trying was the constant rumors that ARCO gas yields terrible MPG. When it was easier for me to afford gas, I would religiously use Chevron. In the town I grew up in the price difference wasn't so astronomical though either.

I wanted to see for myself. It's good enough to call the rumor BS, I don't need more.

 

[dyeager535]

I remember when the gas station chains got smacked down for trying to make people think they needed higher octane gas. Their marketing for "quality" is similar, it makes sense people start believing it at face value, and thus justify paying the higher price.

I figure if I can get upwards of 300k miles on multiple vehicles with no issues, gas brand isn't a real concern.

 

[imiceman44]

I remember when the gas station chains got smacked down for trying to make people think they needed higher octane gas. Their marketing for "quality" is similar, it makes sense people start believing it at face value, and thus justify paying the higher price.

I figure if I can get upwards of 300k miles on multiple vehicles with no issues, gas brand isn't a real concern.

Well Costco has the cheapest gas so I am not fooled into paying more

 

[K85 Octane]

You know how they say history fades away with people's memory and things change all the time without the population really knowing.

At some point, I'm calling it 20 years ago, the red and blue switched their octanes. I got fooled the moment they did it but quickly changed back. This might have been a Chevron only thing but RED 87 used to be on the left, BLUE 91 was on the right. It even made a lot more sense back then (RED WHITE and BLUE) Furthermore, Chevron's color is BLUE, so wouldn't they have the "best" octane with their color? Was there a problem or did they just try to get buyer's to buy 91 for the first few fill ups after the switch?

Can anyone verify? (I should say, "remember") cause everyone around me looks at me funny when I bring this up.

 

[Blue85]

Have no Chevron, Arco or Costco around here, so I can't help you.