Does using 87 Octane cause damage to my engine? Do I get a performance benefit if I use higher octane fuel?
Using 87 Octane, if your engine does not knock, will not damage your engine. The engine software detects knock, and will retard spark timing automatically to eliminate it. If you hear engine knock, it means that your engine has retarded the timing as far as it can go, and you should increase the fuel octane you are using. The base calibration for the engine is set to perform best with 91 octane fuel. Running at 87 octane in most conditions will have some effect in reduced performance (acceleration) but may or may not be detectable and is dependent on the driver. Running low octane fuel in high temperature conditions like today (100 degrees) is most certainly causing your engine to retard timing to eliminate knock. The higher the temperature outside, the more performance effect you may detect using 87 octane fuel.

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