Is high-octane petrol better for your car?
Some motorists swear by high-octane fuel and insist on only filling up with 98 RON. Others go a step further and only fill up with the most expensive blend available, believing that the added cost is worth it, because it results in better performance.
Yes, high-octane fuel will give you better performance, but only if it’s what the car manufacturer recommends for your model. So if your owner’s manual says that 92 RON or 95 RON is optimal, I suggest sticking to that.
Only high-performance or very highly tuned cars require high-octane fuel. The higher the octane number, the higher the fuel’s resistance to premature detonation or “knocking”.
Knocking occurs when the yet-to-be-combusted fuel-air mixture ignites prematurely due to the combination of hot temperatures and the pressure from a motor’s high compression ratio. These factors are usually only present in highly tuned sports cars. No offence, but if you’ve got a regular runabout, it’s unlikely that it’s going to need high-octane fuel.
Another reason why you probably don’t need high-octane petrol is the fact that most modern engines have anti-knock sensors. Coupled with advanced ECUs (engine control units), today’s engines can effectively modify the engine’s state of tune to prevent knocking from taking place.
Therefore, even if you did drive a sports car, but mistakenly filled up with 95 RON instead of 98 RON, the engine can reduce the power output to prevent premature combustion. This is why owners of high-performance sports cars will complain of reduced performance when lower octane fuel is used. In addition, do remember that a higher-octane fuel does not contain more energy than a lower-octane one.
On a final note, I once interviewed a top executive at a petroleum company. When I asked him if motorists would get better performance by filling up with high-octane petrol, he simply replied: “Motorists should just follow what their owner’s manual recommends.”
