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What octane and brand?

5K views 28 replies 25 participants last post by  05 llbean 
#1 ·
So I am curious, if you have seen another post of mine, you will see that we have not been getting the mileage has hoped in our 2013 2.5 limited outback. So we are trying to think outside the box. We are typically filling up at Kroger grocery stores when possible or inexpensive gas stations (Racetrack, etc) I do not fill up at Costco or Walmart. We are using 86 octane. I am curious, what brands of gas are you typically seeing to have the best mileage. What mileage are you getting with that. Also, have you noticed if going with a higher octane improves the mileage enough to justify the extra cost? Obviously, summer and winter blends and levels of ethanol can impact this, I was telling my wife that maybe kroger's gas might have something to do with our mileage and to try something else. She was concerned about the price increase and I told her that if we got 2 more mpg by spending a little more per gallon, we could actually see a total monthly gas savings that could be worth it given how much we drive.

What do you say?
 
#2 ·
the base gasoline used by most retailers in an area all comes from the same terminal - but which and how much ethanol, detergents, etc. are put in can vary. Most likely, you'd be better served by staying with a high-voluime retailer like Kroger and throwing in some off-the-shelf Techron or Seafoam every 6 months to 2 years or so.

'most' of our gas actually comes from Kroger or Costco too. The other day my wife got 60 cents per gal off with her kroger card! She drives an 03 and we have always used premium as suggested by the manual. I doubt you'd see even a remote improvement by using a higher grade gas than recommended in your manual. That would be a waste of money.
 
#5 ·
Octane rating has zero impact on mileage with the 2.5 it was designed for the cheap low octane fuel. The higher the octane the more stable the fuel which is why hotter harder running performance engines require higher octane. Your car is new doesnt have very many miles on it and its winter time. Shelve your mileage expectations till you have 15,000 miles or more on your car!
 
#3 ·
Costco is the cheapest around here but I refuse to sit in line for 15-20 minutes waiting for people standing at the pump digging around in their purse or wallet looking for a card they knew they would be needing to get out the last 15 minutes while they were waiting in line so I buy almost exclusively Arco 87 because it is the 2nd cheapest around here and I never have to wait in line, my average is 28.7 probably a 70 highway 30 city mix
 
#8 ·
Based on the time of year it is, your mileage is probably being hurt by starting the car and letting it warm up in the mornings..


The only time I notice much of a difference in my gas mileage is if I can find a station that has gas with no ethanol in it, which is nearly impossible to find around here anymore. So, I usually run QT Regular Unleaded..

There's a Valero gas station a little closer to my house than the QT, but the car (and the truck I had before the car) seems more likely to clatter with Valero's gas. So, I skip Valero (at least that Valero) these days..

Running higher octane than the manual calls for probably won't net you anything at all and even if it does net you a slight increase in mileage, it probably won't be enough to offset the cost-per-gallon difference..
 
#10 ·
Top Tier Gasoline

I try and use a top tier gas, if possible, but it shouldn't give better mileage but it could help the fuel system stay cleaner with fewer deposits - or you could just use the Chevron Techron cleaner on occassion with any brand. I once heard - probably somewhere on the internet so might be questionable - that auto makers use Chevron when they certify their vehicles with the EPA.
 
#11 ·
Chevron, Shell or Texaco (the cheap stuff) for me, my OB (3.6) gets almost 28 on the highway.

Vince
 
#12 ·
The issue for MPG improvent is ethanol or no ethanol in your gas, not octane. Ethanol has lower BTU energy that gasoline so it will negatively affect gas mileage (in additon to being corrosive to engines not designed to handle it). But at least we divert our food supply to produce a crummy government mandated and subsidized, environmentally harmful fuel additive (note sarcasm). In the rare case I can find no-ethanol premium fuel I will use it. In Wisconsin about the only way to avoid ethanol is to go to dedicated premium fuel pumps that are outside of southeast Wisconsin. When I use ethanol free premium gas I document a 2-3 MPG improvement. Not a huge improvement but noticable.
 
#13 ·
I don't know your stations in the US but all I can add is stick with regular, here it is 87 octane. Stepping up won't net you anything but more fuel cost. I don't think we can get any fuel here anymore without ethanol, for a few years now, at least I haven't found any.
 
#14 ·
I've almost always used Costco gas in my '11 3.6 since getting it (and even before that with my T4R), and have never had a problem. If you get to the station early in the morning or late at night there is usually no line. Even with a line, I've not waited more than a few minutes, even in Medford Oregon, the busiest station I've been to. This morning in Citrus Heights, I was one of only three at the pumps at the time I arrived.

I use Costco because of the rebate I get for using AMEX (paid in full each month). I tried Chevron for a couple of tanks because others on this forum indicated better mileage. At the price/mileage difference there was no benefit in overall cost, and I didn't notice any improvement in performance. Besides, Chevron put a $100.00 hold on my card each time I used it (meaningless, since i don't come close to the balance, but it was the principle) Ok, you say, use cash--I could, but I chose not to.

JMHO
 
#15 ·
try synthetic oil to boost MPG

I switched to synthetic oil this past summer. I compared my last 10 tank fulls of gas to the 10 tank fulls over the same period last year (to eliminate any seasonal variance) and I documeted a 1 MPG or 3% improvement overall. Not huge but when you factor in the better cold weather starts and longer oil life I find it a net positive. Note: I change my own oil so the cost difference for syntheitc oil is a couple bucks a quart versus regular oil.
 
#17 ·
I use regular. I have many times sat at a restaurant that looks over a Citco sub station watching the barges pump gas off into storage tanks. In the panhandle where I live we get all our gas by barge. Every brand of fuel tanker is there get refueled. I can only guess that the detergent additives and other additives for each formulated fuel is mixed into the fuel pipes filling the tankers. All fuel goes into 2 tanks so clearly the manufacturers must have "their" formulation which goes into the various company tankers. I always assumed each company had their own sub station but here that isn't true.
That said I have noticed no difference in mpg using various fuels in my area. However now that the OB is up north for a few months and it is 30F out from 70F I have noticed a 3 mpg loss. Maybe it is the fuel formulation or the temps or most likely both that caused this.
I don't know what higher octane would do to my mileage. I suspect nothing since higher octane isn't needed to reduce knock...
 
#18 ·
I'm not really a bargain shopper when it comes to gas, I buy from whatever is closest to me at time I need to get gas. As an example I always try to fill the car up for my wife so she doesn't have to. So she will come home for work and say Ohh I need gas for the car, so I end up going to fetch gas just before I call it a night so to speak, basically I'm always going to the closest station to the house. There are at least 20 stations near me and they are all within 10 cents of each other +/- so I don't lose sleep over that.

With that said, my car struggles to pull of more than 27 mpg, and will if the highway is flat as a board and cruise is set 68-70. But it will easily get at least get 27 mpg. In the cars defense, we do have two fork mount type Yakima bike racks on the roof, so not sure if that is causing the drag.
 
#19 ·
76 Ethanol Free for me. It's only half a mile further than the Shell near my house so it's worth it. I have seen a slight bump in fuel economy since switching to the ethanol free petrol. If I can't find that, I go with Shell.
 
#20 ·
I buy 87 at Costco, runs just fine.
Costco always has fresh gas too, trucks make a dump at least twice a day at my busy station.
 
#21 ·
My 2013 6-cylinder Outback is 7 weeks old with 3,900 miles and has been averaging 23.8 on the MPG Display (22.8 actual) with a lot of short trips (50% city / 50% highway).

Have recently upgraded engine, trans, and differential fluids to Group IV & V synthetic fluids and run 38 psi in front tires and 35 psi in the rear with 87 Octane Mid-grade fuel from Chevron. Average temperatures range from 30*F to 15*F.

Merry Christmas!
 
#22 ·
Ventura to Mammoth Lakes w/ 1000 miles on the ODO, I averaged 26MPG. Shell Gasoline

Mammoth Lakes to Ventura w/ 1400 miles on the ODO, I averaged 29MPG. Gas from an Indian reservation in Bishop.

I drove 70MPH on the way up, and ascended from sea level to around 8000 feet. On the way back I drove around 65MPH and descended to sea level.

It's either your driving style and MPG expectations are incongruent, or you've got something wrong with your car. Good luck with it.
 
#23 ·
Costco is 20-40c cheaper per gallon in our area, and has their 'clean power' detergent additives, similar to the brand name stations. I always try to purchase from the highest volume stations to reduce the chance of water contamination. We don't have ethanol-free gas available in my area.

There are 134 operating refineries in the US. Some gasoline is also imported (mostly from Europe). If you take away California (16) - especially with the wide variety of formulations required so you might see some variations there- each state except maybe Texas (27) is served only by handful of refineries. The Congress mandates ethanol mixtures most areas too. There is no way that there can be any significant variation based on any sort of additive mixture, unless the additives are insufficient to keep injectors clean. Every branded oil retailer has a effective additives and quality assurance procedures to keep contaminants out of their products. Many are identical (e.g. Speedway/Marathon).

This whole discussion is all about the power of marketing and branding. I'd just buy from whoever is cheapest and most convenient. Gasoline of a particular octane is a commodity with one price. If there was a difference, it would be graded like agricultural products.
 
#24 · (Edited)
I deliver gas for a living and I recommend only tier 1 gas

Most of the gas comes from the same places what makes it different is the amount of cleaning additives that is put in. no brand name gasoline is tier 2-3 gas with the minium amount of additives required by federal law.
Tier 1 gas has roughly twice the cleaning additive as low price gasoline. phillips 66/conoco gas has 2 1/2 times the cleaning additives a low price gasoline. I would contact subaru and see if you can obtain a list of tier one gasolines that are available.

If you are at higher altitude I still would not go below 87 octane because it you go to a lower altitude it could cause your car to ping and pull timing causing worse fuel economy. I also recomend that you avoid gas with ethanol in it if you have a choice to get 100% gas. 100% gas will get you 10% better fuel economy. Absoultly avoid gas with more than 10% ethanol. If you car sets a lot or you use e 10 use a additive like stabil ethanol gas treatment. Ethanol is hydroscopic meaning it pulls water out of the air over time and can carode your fuel system from the inside out because the water turns the fuel acidic.
 
#26 ·
Sorry for my ignorance, but how do you find a station that doesn't use Ethanol? The only way I know of is to go there and look at the pump. Is there an easier way than searching the hundreds of local stations one at a time?
 
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