RON95 for 240?

With recent government introduction of RON95 petrol, most petrol station diminished their RON97 products; and drivers are mostly left with RON95 option. There's a lot of argument on this RON issue, some says its a low-grade fuel, some says it is not compatible with modern cars, etc.

What is RON? RON stands for Research Octane Number. Fuels are chains of hydrocarbon (CH chains). The more stable the chain are, the more strong chemical bonding occurs between them. This will result in more output power when being burnt. Higher bond are indicated by higher RON. Contra to that, lower RON indicates that the chemical bonding of the hydrocarbons chain are weaker. They might get burnt pre-maturely; for instance, upon compression in the engine, and when spark plug is about to on, it gets combusted already. This resulted in two things; pre-mature burnt causes 'knocking' while weaker bond gives lower output power.


How to know whether you engine are design to accept which RON? Your owner's manual is always the best resource. For this Volvo 240, it is stated that minimum RON is RON87 while the most recommended fuel is RON91 and higher. Thus theoretically RON95 should be no problem. I also had refuel RON95 twice; and no problem at all, did not notice any lacking though. Just the same performance. Perhaps 97 and 95 are not differ so much that will produce obvious performance difference.

So, RON95 is OK for this old brick!