Octane Rating
The octane rating shows how well petrol resists knocking, the uncontrolled ignition of the mixture.
What is Octane Rating?
In Europe the RON number is used (for example 95 or 98); in the US the pump number is the average of RON and MON (for example 87 or 91). Higher octane does not mean more energy; it means more resistance to knock. High-compression and turbocharged engines often need higher octane.
How it works
The engine control unit uses the knock sensor to retard timing if knock appears, protecting the engine.
Why it matters for your car
Using lower octane than specified can reduce power and, under heavy load, risk damage. Using higher octane than needed rarely brings measurable benefit.
Other terms
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- V6 Engine