RON95 Vs RON97 – Here’s What These Engineers Have To Say About Their Power And Compatibility

With the recent increase in the price of RON97 in the local market, the question of the RON difference has resurfaced. Many people are wondering which RON is best for their vehicle.

To feed your curiosity, Dr. Aid Fawzal, an engineer currently working in the UK and Ir. Fadzil ZA, an Engine Performance Analysis Engineer glad to share their views and thoughts related to this matter.

RON 95, 97 and 100; What makes them different?

Basically, the energy value (calorific value) for petrol with RON 95 or RON 97 or RON 100 are all more or less the same. What differentiates is the quality against the anti-knock quality. Since the energy content is the same, there’s no difference in terms of ‘power’.  

While the use of RON95/RON97 was previously closely related to the engine compression ratio, this is no longer the case for modern automobile engines. Car engines can now change tuning based on the RON used, thanks to the advancement of increasingly complex and sophisticated technology.

For example, the Mazda Sky-Activ G engine. The engine is a natural aspiration with a compression ratio as high as 14: 1. In general, it should use RON100, but in this case it doesn't. With the modern and advanced combustion chamber design and tuning, RON95 is all that is required.

Talking about compatibility, high RON is more suitable for use for engines that use forced induction (forced induction) such as supercharger (SC) or turbocharger (TC). This is because engines with SC/TC are more prone to "knocking" due to the incoming wind pressure and high temperature. High RON is said to reduce or prevent the occurrence of a drop in performance as well as damage to engine components. 

Do ALL SC/TC engines use high RON?

No, not always. This is due to modern ECUs being tuned to operate in various RON ranges. For instance, the range is RON 87 to RON 100. Nonetheless, the RON level recommended in your car's manual/specification book will result in the best performance rate and the best fuel consumption.

However, using inappropriate RON or exceeding the allowable range stated may exacerbate the 'knocking' effect because the ECU is unable to control it properly.

Because unit of measurement is a significant factor here, neither the 95, 97, nor 100 is more economical. However, it is important to use the correct RON for your vehicle's engine based on the specifications. However, if you want to use a different RON, it will not directly harm your engine.

To summarise, engines designed for low RON can perform well when used with high RON. However, engines designed for high RON will not work well with low RON.

The choice is yours. CHOOSE WISELY!