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If there isn't any engine pinging, is there anything else that could cause a problem from using gas that is lower than specified by the manufacturer? I see a lot of threads in various places questioning whether it's ok to use a lower octane gas in an engine that the manufacturer specifies using a high octane gas. Modern engines make adjustments for lower octane. If there isn't any pinging, is there anything else that could cause a problem from using lower than specified octane gas?

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For modern day fuel injected engines, when the engine detects ping or pre-detonation, it pulls timing. When this happens, the engine loses power. There's a couple of things, though. The ECU can only pull so much timing and have the engine continue to run. When you get to this limit, damage may ensue. A large problem with ping is, you won't notice it but in the most severe cases. If you're running and ping is occurring, you could be causing damage to your engine and never know it until something catastrophic happens.

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  • As the ECU retards spark to stop ping/knock , engine power is reduced. As I have been driving little using little gas the last year, I have been using premium in my 2011 Murano. The increase in power is very noticeable. Mar 1, 2022 at 0:57
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    @blacksmith37 - Sorry to tell you, it doesn't work that way. Extra octane in a vehicle which does not require it, like your Murano, just burns expensive fuel without any benefits. If you're feeling any difference in performance its because your butt dyno needs calibrating ... IOW: your brain is making it up. Mar 1, 2022 at 1:36
  • fwiw, i don’t push it too much, but i don’t detect any reduction in power or pep using 87 octane! must be the quality costco gas! i will investigate if this car has some sort of warning if it computes that it can’t retard the timing enough. i hate to think that the low octane is causing a problem! i accidentally put regular in, and didn’t notice, so i tried a fill-up with it and still didn’t notice. it's a 2019 mini countryman-S I4
    – rebar
    Mar 1, 2022 at 5:47
  • @rebar - If you don't push it at all, you probably wouldn't notice it, however, the one time when you need to push it, you're really risking your engine. Your Countryman-S is supercharged (I believe ... could be turbo'd) requires the extra octane due to it being boosted. Without it, ping is a real factor under load. Mar 1, 2022 at 10:35
  • My interest is provoked; The VQ 35 DE engine may be unusual. The owners manual is not much help. Internet sites say the engine has been used for years in many variations; compassion is 10.1 to 10.5, HP varies from 225 to 300. With that much compression, high octane could be productive depending on how the ECU manages advance. Net sources say it should have high octane but my manual does not. I am inclined to trust my butt dyno for now. Mar 1, 2022 at 18:51

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