Gas!!
If you drive gently, nothing happens. The car runs as normal. If you accelerate quickly/apply heavy load to the engine, you will get some knock activity. The ECU will detect that knock activity, reduce timing and reduce power.
There is a set amount of timing advance built into the ECU. It will not advance the timing past that point, which is set for high octane pump gas (91-92?), so using higher octane (like race gas) is useless.
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To Anyone: Will my SL500 run better on 93 octane or is it just helpful to cars with a higher level of tuning -- like your AMGS?

But I was under the impression that you were using 93 octane in your car. I guess I misunderstood.
Will such high octane hurt the engine? Or is it a general rule that the higher the octane, the better?




