RON 95 and RON 97 Petrol
RON stands for Research Octane Number, is most commonly used Octane Rating to
indicate the grade of Petrol.
Higher the octane rating of the fuel will withstand higher compression ratio in
the piston compartment of an engine, before self-ignite. And, generally engines with high-compression ratio require
higher octane number to prevent Knocking caused by self-ignite.
Nowadays, engine equiped with micro-chip control unit usually comes with
knock-sensor, which controls the ignition timing to reduce knocking effect. But also reduce power output and fuel
efficiency of the engine. Thus, high performance engines usually require higher octane fuel to ensure consistent
Lead in the form of tetraethyllead was once a common additive, to prevent engine
Knocking Effect. But due to its harmful exhaust gas from engine emmission, its use for fuel additive
especially for road vehicles has been progressively phased-out worldwide, since 40 years ago.
In Malaysia, RON 92 had been used until 2009. Then, replaced with unleaded RON 95
called "regular", and RON 97 is rated at "premium" grade. RON 95 is subsidized by the government thus selling at
much lower price. But RON 97 price fluatuates based on Crude Oil price movements.