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What octane and brand?

4431 Views 28 Replies 25 Participants Last post by  05 llbean
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?
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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.
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
I do best with gas stations with oil company branding- shell, texaco, 76, Mobil etc. they usually aren't the cheapest, but I like getting more range, fewer stops.
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.
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!
Costco gas in the Seattle area has additional additives.

Gasoline Clean Power

Kirkland Signature Clean Power detergent additive (UltraZol 9888) is manufactured by Lubrizol and registered with the EPA.

Powerpoint on what is involved in adding the detergent to the gas

Costco gas additive presentation
87 octane from Exxon, Shell, Mobil, as long as there's no ethanol in it...Which is becoming harder to find.
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..
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87 octane from Exxon, Shell, Mobil, as long as there's no ethanol in it...Which is becoming harder to find.
I definitely had better mileage on the 100% gasoline, but the only station left in the area is far enough out of my way to negate the mileage boost.

:(
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.
Chevron, Shell or Texaco (the cheap stuff) for me, my OB (3.6) gets almost 28 on the highway.

Vince
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.
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.
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
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.
I get the lowest MPG at Kroger and the best mileage at Chevron.
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...
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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.
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.
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.
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