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2019 Forester Sport CVT
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Safe? Lead free? Ethanol content?

Anti-knock sensors adjust timing for octane but it takes several restarts to overwrite the adjustments. It is prudent to always use the same octane.

One can force a rewrite of the computer settings by disconnecting the battery for a while.

10% ethanol, or less, led free 100 octane? Go for it. Can’t hurt. It’s the switch back to pump gas that will hurt as the computer will have adjusted to the higher octane by advancing the ignition timing.

Track day? Go for it, just rewrite the switch back to pump gas by disconnecting the battery.
 

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2017 Forester XT CVT (High Torque)
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I found a local 76 dealer with "racing" fuel. :surprise:

This isn’t worth it without a tune, unless you run it all the time. It takes the computer a while to adjust to new fuel, and it will never take full advantage without adjusting the map.

The one exception is if you don’t have access to 93 octane (California has 91). Then you can mix in some higher octane to bring the average closer to 93.

I’ve done this with 105 racing fuel, just a few gallons before filling with 91. It was great for one tank for getting over the mountains with a packed Foz and roof rack with two bikes on the hitch. However, when I switched back to straight 91 I had stuttering and hesitation for a while.
 

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Huge waste of money. You have a a grocery getter that is in the upper (but not top) tier of power. ..rd a nice sporty vehicle....period
 

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2016 Forester XT
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The one exception is if you don’t have access to 93 octane (California has 91). Then you can mix in some higher octane to bring the average closer to 93.

I’ve done this with 105 racing fuel, just a few gallons before filling with 91. It was great for one tank for getting over the mountains with a packed Foz and roof rack with two bikes on the hitch. However, when I switched back to straight 91 I had stuttering and hesitation for a while.
Agree with this. I live on the west coast and can usually only do 91 or 92 octane. In Vancouver, BC, I was able to buy 94 (I think it was 94) octane gas (much pricier than their 91 though..). That was the smoothest my engine ever ran, but also remember I can never usually even run with 93 octane. The downside was after my next fill up of 91/92, I had knocking and stuttering for a tank or two until the engine downtuned again :(

So, it is a fun experiment, but the results afterwards and cost of using higher than 93 might not be worth it.
 

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2015 Forester 2.5i CVT
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Safe? Lead free? Ethanol content?

Anti-knock sensors adjust timing for octane but it takes several restarts to overwrite the adjustments. It is prudent to always use the same octane.

One can force a rewrite of the computer settings by disconnecting the battery for a while.

10% ethanol, or less, led free 100 octane? Go for it. Can’t hurt. It’s the switch back to pump gas that will hurt as the computer will have adjusted to the higher octane by advancing the ignition timing.
X2

This isn’t worth it without a tune, unless you run it all the time. It takes the computer a while to adjust to new fuel, and it will never take full advantage without adjusting the map.

The one exception is if you don’t have access to 93 octane (California has 91). Then you can mix in some higher octane to bring the average closer to 93.

I’ve done this with 105 racing fuel, just a few gallons before filling with 91. It was great for one tank for getting over the mountains with a packed Foz and roof rack with two bikes on the hitch. However, when I switched back to straight 91 I had stuttering and hesitation for a while.
Agreed.

Nope, they have Sunoco 105 at a 76 station in Woodside. Lots of venture capital types with exotic cars around there.

Kings Union 76
975 Woodside Road
Redwood City, CA 94061

There is another 76 station in Saratoga Sunnyvale Road, too. Here’s the fuel finder:

https://www.sunocoracefuels.com/fuel-finder?city=&state=California&zip=94061&fid=&range=300
I know where that station's at. Good to know, thanks! :)
 
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