3 ms·

And just to highlight and explicitly explained the weird edge case that GP mentioned... On many modern cars, high octane gas gives you more boom. They are des

• mrguyorama 3y ago
  This is probably not true of modern naturally aspirated cars. Maybe they could lean out the mixture a little to get a bit more efficiency on higher octane, but they largely can't leverage the higher octane fuel as well as a car with an electronically controlled turbocharger system. >They are designed for high octane gas The vast majority of modern engines are designed for 87 octane, and not downrated to 87 octane, because that would give you poorer performance than a clean sheet 87 octane design, and single digit percentages matter here.
  • mlyle 3y ago
    > This is probably not true of modern naturally aspirated cars. There's a whole lot of cars that say "Use premium fuel only" with compression ratios of >10.5:1, but rely upon anti-knock sensors to retard timing (and adjust mixture) to avoid detonation with 87 octane fuel.