Monday, November 24, 2014

What Does RON95/RON97 Stands For And What You Should Know About It

First of all, starting on 1st December 2014, the government will remove the subsidies on RON95 and diesel fuels. That would mean that instead of paying a subsidised price of RM2.30 per litre now at the time of writing, we will have to pay the full price which is RM2.43 per litre for RON95 and RM2.32 per litre for diesel. That will be an additional 13 cents per litre for the fuel that we use everyday! 

November 2014 petrol price.
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I don't want to complain about the subsidy anymore because it wouldn't make a difference anyway but since RON97 is just 12 cents short of the unsubsidized RON95 (RON97 priced at RM2.55 per litre now), should you pull the trigger and pump RON97 petrol into your car?

First let's take a look at what RON95/RON97 really means.

RON, the acronym for Research Octane Number, stands for the octane number in your fuel. Octanes are hydrocarbons that basically made up most of the petrol that you pump into your car every time you are at the petrol station (besides some other hydrocarbons and additives). That being said, RON95 means the octane number of your fuel is 95. Be mindful that RON95 does not means that the fuel is made out of 95% octane!

I believe that you can work out that RON97 has an octane number of 97, duh.

We often hear from our parents, friends and colleagues that using RON97 is better, and how the fuel will help to "protect" our engines, but do we really know how it works?

Do you even know what does those numbers behind RON stands for?
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A higher octane number means that the fuel has a higher compression ratio. The fuel will be able to withstand more compression from the piston before it ignites and burn perfectly to push the piston downwards again to generate movement. Technical aside, a lower octane number fuel cannot withstand a higher compression force from the piston and will ignite more easily (or explode!) which leads to pre-ignition and will usually cause engine knocking as well, and those two things don't do too good to your engine walls.

However, there are some cars that are only able to use RON97 fuel or any fuel that has higher octane number because 97 is their minimum octane number, just like how most of our cars have minimums too. We cannot pump lower than minimum octane number fuels into our engines or you have to pay for the consequences-lah. If you pump the obsolete RON92 into your car, you might hear some knocking noise coming from your engine. Each manufacturer has a different minimums, that being said, I am sure most of our cars have RON95 as the minimum.

But, if you have been using RON95 all the while and it does not causes any engine knocking, you really don't have any reason to change to RON97 at all. The main reason why people need to use RON97 is because their engines are knocking with the RON95. Why do you want to use a better fuel if the problem doesn't affects you? Maybe some speed? Apparently, RON97 fuel does not give you the extra power you need but if you change to a lower octane number fuel below the minimum standard set by your manufacturer, your power and speed will decrease dramatically (somehow caused by the engine knocking issue)!

Only those engines that are DESIGNED to work with high compression ratio fuels will be able to take advantage of the higher octane number fuels, leading to higher power output and speed. 

Yesterday my friend told me that we cannot mix RON95 and RON97 fuels together cause it is bad for the engine. I was unwilling to believe that because I myself have tried mixing them up and apparently my engine is still working just fine. I told my friend that I will do more research on it and here we are, the purpose of this post! Contrary to what my friend heard, we CAN mix them together. It will not cause any noticeable adverse effect to our engines and will also not cause any additional improvement as well (refer bolded words above).

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So the next time you step into the petrol station, decide first which fuel is better for you and your engine (by you I mean your wallet-lah! HAHAHAHA).

TLDR version: If you pump RON95 your whole life, continue to pump it unless you got extra money for RON97 or your engine is producing knocking noise with the RON95. 

Discussion is welcome!


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