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Discussion Starter #1
Has anybody used Premium in the 3.6R any Mpg boost or acceleration?

crm
 

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2016 3.6 Limited with ES
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I've done mid grade on very hot days in the Vegas area and there was no zing or zippity doo dah.

In mountain areas you'll see 85 and in hot areas higher octane held but as a general go by, 87 is fine.
 

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2017 Outback
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you are asking the wrong question
premium costs substantially more, for example, if it costs 20% more, it better give you 25% more mileage or it isn't worth it
no, using premium gas is not cost effective


on the other hand, some people might be willing to pay 70 cents a gallon for gas that gives them a 1% boost in HP, even if the boost is in their head


but keep in mind burning premium in your 3.6 allows you to demonstrate to 2.5 owners that you have money to burn
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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It's not tuned for it, so unless you get your car retuned (here's look at Ed from XRT) there is no real benefit under normal conditions.
 

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2015 Legacy 3.6R ES, 2014 Forester Touring ES, 2005 Jeep Liberty Limited
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It's not tuned for it, so unless you get your car retuned (here's look at Ed from XRT) there is no real benefit under normal conditions.
^
What he said.

Laughing at oneself and with others is good for the Soul!
 

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2017 3.6 limited Outback
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Premium gas isn't a better gas, it offers an engine the ability to burn quicker timing or higher compression with less chance of knock. The fact is regular gas has more available energy potential than premium. The question then is, can your engine gain anything from running higher timing and or more compression. Compression is not changeable, timing is a variable if you are willing to get into your ecu and do some warranty destruction. Your Subaru Outback is tuned to run on regular gas. Using premium is not going to help your engine unless there are issues with your engine. The best thing you can do is be sure to run top tier gas. And that is only because you can be certain you are getting well-engineered detergents. From what I have heard all major gas (within octane rating) is the same, the difference is the detergent packet added when the tanker leaves the distribution supply yard. Apparently each Major runs a specific detergent which might do a specific job of "cleaning". Unfortunately, one cleaner might not be the only one your engine needs. It's suggested you vary the gas Brand you use occasionally.
 

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2015 Outback 3.6R Package 23
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The whole point of me buying a 3.6R was that it runs on 87 octane fuel. I spent 14 years driving European turbos where the knock sensor would kill the boost if you ran anything less than 91 octane fuel. That was fine in 2001 when the price spread between 87 and 91 octane was 20 cents. It's now 50 cents at most gas stations around me.

91 octane will not improve the performance of a 3.6R Outback. It doesn't have high enough engine compression to knock even climbing hills under load. I don't have 85 octane fuel where I live so I don't know how that performs. 87 is what I use.
 

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Outback 1: 2015 2.5i Limited. Option 23, PP5, Hitch. Ice Silver. Outback 2: 2015 2.5i Limited, Option 23, PP5, Carbide Gray.
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I second what Bbb said above relating to Top Tier Gas. Do an internet search for brands that are Top Tier Certified.
 

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2017 3.6R Limited with Eye Sight
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And, unlike the 3.6's wimpy little 2.5 brother, it doesn't require synthetic oil.
 

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It would be possible to see a slight mileage gain with premium gas but it wouldn't have anything to do with the octane rating. At many stations the premium gas doesn't contain any ethanol so compared to the 87 octane with 10% ethanol there could be a slight increase in mpg. Probably barely noticeable and certainly not enough to offset the higher price of the premium. In another thread someone pointed out that it isn't automatic that premium doesn't have ethanol. If it isn't labeled on the pump as ethanol-free it probably isn't.
 

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2016 3.6 Limited with ES
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Well there's also the winter vs summer gas blends.

Winter gas has either butane, propane or isotane or some sort of 'tane in it to improve the gas but all of those have pretty poor BTUs compared to gas.

I think we switch to summer gas in a couple of weeks so your car ought to run better.
 

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Actually,if I understand correctly the opposite might be true! Ethanol boosts the octane level.

It would be possible to see a slight mileage gain with premium gas but it wouldn't have anything to do with the octane rating. At many stations the premium gas doesn't contain any ethanol so compared to the 87 octane with 10% ethanol there could be a slight increase in mpg. Probably barely noticeable and certainly not enough to offset the higher price of the premium. In another thread someone pointed out that it isn't automatic that premium doesn't have ethanol. If it isn't labeled on the pump as ethanol-free it probably isn't.
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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And the overpowered 3.6 owners get to crawl under their car to change oil filters. No wait, they don't want to get their hands dirty.
I like crawling under my cars. I like to get my hands dirty on the undercarriage. There is no better monitor than to get to know your car well enough to see the changes. Kinda like having kids.

If you just want to look at a pretty engine cover and that's it, then bring on the electric automation.
 

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2015 Outback 3.6R Package 23
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From what I have heard all major gas (within octane rating) is the same, the difference is the detergent packet added when the tanker leaves the distribution supply yard. Apparently each Major runs a specific detergent which might do a specific job of "cleaning". Unfortunately, one cleaner might not be the only one your engine needs. It's suggested you vary the gas Brand you use occasionally.
Where I live, all gasoline comes from the same set of tanks at the port. I'm in a 10% Ethanol state. The additive package really doesn't matter much since E10 is a perfectly good solvent to keep your injectors clean.

E10 is a PITA with boats where the fuel tends to sit for months. Ethanol absorbs water. ~50x more than Ethanol-free gasoline. That causes all kinds of issues because bacteria breed in the water and gum everything up.
 
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