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A comment on How does a gas pump know to shut itself off? (1981). Parent comment

Re:How does a gas pump know to shut itself off? (1981) by kortilla on Saturday October 10, 2020 @07:11PM (#24742580)
No, the main point of high octane fuel is to be resistant to higher compression ratios so it doesn’t pre-detonate. Spark plugs have no issues igniting it.

What op is referring to is additives that are added in by some gas dealers to the high octane fuel to upsell you. “Techron” is one I recall seeing at Chevron IIRC.

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Re:How does a gas pump know to shut itself off? (1981) by pxx on Saturday October 10, 2020 @07:39PM (#24742732)
You can sometimes buy the additives separately. e.g. for Techron: https://amzn.to/33LH1RN
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Re:How does a gas pump know to shut itself off? (1981) by herdrick on Saturday October 10, 2020 @07:32PM (#24742703)
The parent comment is right. It's not just the spark; heat and pressure are also part of what ignites your air/fuel mixture.
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Re:How does a gas pump know to shut itself off? (1981) by kortilla on Wednesday October 14, 2020 @12:42AM (#24773143)
Not with gasoline. A gas engine can ignite at temps well below 0F and low compression.

You might be thinking of diesel. Diesel depends on compression to combust and has heater coils to ensure minimum temps as well.

This is more obvious when you read engine specs and they have minimum octane ratings, not specific ratings.

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