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Discussion Starter · #1 ·
Just got a 19 Premium last week. Other than the driver’s seat, which I detailed in another thread, I’m loving it.

So there’s an Exon-Mobil less than 5 minutes from our house. Should I be using their Synergy Supreme + 93 rated octane? With a new vehicle, and given that the manual recommends 87 at a minimum (seems like they want you to go higher) I want to make sure I’m protecting my engine from jump.

87? 91? or 93?
 

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2019 Subaru Forester CVT
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43 Posts
My last car needed premium so my Forester with regular or mid grade seems like a downright bargain. I confess to have been using mid grade (89) most of the time. Old habits are hard to break.

Your engine will adjust timing to use what its fed, gas wise. If towing or driving up hilly areas, bumping up to the next grade or two will not hurt.
 

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2019 Forester Touring CVT
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57 Posts
I really don't know where I read it and I swear I read the manual a few times, but I thought I saw higher than 87 AKI which is what I've been putting in the car, but as Rawland pointed out, the manual does say 87. Awesome.

TS out (getting new reading glasses)
 

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2019 Forester - Touring CVT
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137 Posts
I run regular, 87-octane in my Forester with no engine knock. In my Forester "Quick Guide", pg 26, it says "regular unleaded gasoline with an octane rating of 87 or higher".
 

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2015 Forester2.5i Premium CVT
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1,301 Posts
So there’s an Exon-Mobil less than 5 minutes from our house. Should I be using their Synergy Supreme + 93 rated octane? With a new vehicle, and given that the manual recommends 87 at a minimum (seems like they want you to go higher) I want to make sure I’m protecting my engine from jump.
Exxon and Mobil stations sell Top Tier gasoline, and your engine will definitely benefit long-term from sticking to this detergent formulation. Most name brands are also TT these days, and it costs little if any extra to avoid off-brands that aren’t. See https://toptiergas.com/licensed-brands/ for the list.

Yes, 87 Octane is the requirement, as noted.
 

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Discussion Starter · #10 ·
If I use 87 regular from Exon, will I still need to add regular engine additives, etc? That initially was the appeal of using a higher octane.
 

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Discussion Starter · #12 ·
You don't need to add anything. Just pump the 87 and drive.
Thanks for all the advice. I was honestly super nervous making the transition to my 19’. My 09’ Altima was so good to me, and while I never had any major issues with it, I wanted to get some value for it while I could.

Subaru just seemed to me to be the type of brand that’s somewhat niche. Certainly not one of the big 3 of Nissan, Honda or Toyota. That smaller brand status scared me a bit at first, but I’m starting to see just why Subi owners are so fiercely loyal, and why Subaru overall has such great brand loyalty.

I don’t mind going with a smaller company if they put out competitive products. All the research I found told me that the CRV and Forester were 1-2 and you couldn’t go wrong with either. Just had a feeling the Forester would be a better car. So far, I feel like I’m right!
 

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2019 Touring
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In addition to using “regular” gasoline I like adding Techron (Chevron) for fuel injection system health. IMO it’s a good idea to run some through every 6 months or so.
 

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2013/14 2.5i-L CVT
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That initially was the appeal of using a higher octane.
It will depend on how many miles you drive and the difference in price between regular and premium fuel, but usually adding a bottle of injector cleaner to the tank 2-3 times a year will be significantly cheaper than buying higher octane fuel supposedly containing more detergent.
 

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2014 Forester 2.5i CVT
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87 octane gas is all you will need. At the risk of being attacked by The Faithful, I will tell you that Top Tier gas is not necessary nor is regular use of additives such as Techron nor injector cleaner.
 

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Sahuarita, AZ 2018 Forester Limited
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With direct injection engines, nothing you put in your gas tank will prevent carbon buildup on the backside of the intake valves.
 

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Sahuarita, AZ 2018 Forester Limited
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Interesting to me that "Top Tier" includes Costco but not Sam's Club (Walmart). I have both options near me, but the lines are typically much longer at Costco than Sam's Cub. Maybe that's why?
 

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Sahuarita, AZ 2018 Forester Limited
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But as you said it's DI so no gas flows past the intake valves.
Yes, but that only applies to the 2019 Foresters. All previous years were port-injected where the backside of the intake valves will benefit from the superior cleaning of Top Tier gasoline. Even on the direct-injection 2019's Top Tier gasoline will keep the overall fuel system cleaner.
 
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