Article taken from MotorTrader site,
FEATURE
RON and your car's engine
April 07, 2008 12:20 AM Author:
Chips
The present octane grades of RON92 AND 97 have been in use for decades and in recent years, the government has asked stations to put up such boards to show how much is being subsidised
Now that the general elections have passed, the expected increase in fuel prices is quite likely to occur before long (for obvious reasons, the government had delayed any increase earlier - in spite of oil prices rising substantially in the past year). Over the weekend, the new Minister of Domestic Trade & Consumer Affairs gave an overview of a new approach for the petroleum business which will see a change in the grades of petrol (referred to as RON, or Research Octane Number). If the proposal is implemented, the present grades of RON92 (also referred to as 'Regular') and RON97 (Super), which have been at the pumps for decades, will be replaced by RON95 and RON99. It is likely that the increase in RON will justify an increase in the price per litre, unavoidable since oil prices are very high now and the government subsidies have become a heavier burden.
According to the minister, RON92 has been used 'mainly by motorcycles' but he is probably misinformed by his technical advisers. RON92 is also suitable for many modern engines and even the latest Honda models such as the Civic and CR-V sold in Malaysia are tuned to use RON91 so RON92 is not a problem (in fact, some Honda models sold in Indonesia are even tuned for
RON88). All Perodua models are tuned to run on RON90 and that is a very large number of cars on the road. Those who can use RON92 can save a few sen per litre which, over the long term, still represents a saving in motoring costs (enough for one
roti canai breakfast a week!)
Many motorists have not purchased cheaper RON92 even though their car engine may be able to use it either through ignorance, lack of understanding and even being discouraged by pump attendants who often call this grade of fuel '
Lama' (old). However, there are also valid reasons why some motorists have avoided RON92 even though it can be used for their car. This concerns the additives in RON92 petrol which vary from company to company. The additives are a vital part of the formulation and help to keep the inside of the engine (especially the fuel delivery system) clean so it runs efficiently. It is these additives, upgraded from time to time, which are often the subject of advertising claims of 'cleaner running', 'better fuel economy', etc.
Chevron Malaysia gives the same additive package, called 'Techron', in both its RON92 (Silver) and RON97 (Gold) petrol. The Platinum grade is not sold in Malaysia.
The thing is that because it was perceived in earlier years that RON92 was used by 'low-tech' engine like marine engines, lawnmowers and motorcycles, the petroleum companies felt that it was unnecessary to spend extra money on additives and according to a source in one company, there is almost no additive in that company's RON92 petrol.
Companies like Chevron Malaysia do, however, provide an identical additive package (which the company calls 'Techron') for both grades of their Caltex fuel. As such, the superior benefits which are advertised are not limited only to the RON97 grade. The other company known to also adopt the same approach was ProJet, which is no longer in business here.
Statistically, it may be that the limited number of pumps offering RON92 has led decision-makers to conclude that this grade is 'not in great demand' when in fact, carmakers have been heading in the direction of lower RON for many years now.
The proposed new grade of RON95 is, nevertheless, a good compromise and should be fine for the majority of cars on Malaysian roads. This grade has been a popular one with Japanese manufacturers, possibly because in Japan, their Regular grade has been RON95 for a long time.
The other part of the proposal is to introduce a higher grade of RON99 in place of RON97, which does not make much sense. It will cost more to produce for one thing and less than 1% of all vehicles here would require such a high octane. Even high-performance engines like the Volkswagen/Audi/Skoda FSI engine, the 1.6-litre engine of the Suzuki Swift Sport and the 1.8-litre engine of the old Ford TX3 need only RON98 at most to run at optimum.
However, the interesting thing is that the government will provide a smaller subsidy for RON99 petrol because it is assumed that those who own cars which require such fuel can afford to pay more for their fuel. A larger proportion of the billions of RM in subsidies will be allocated for RON95 to keep its price down since a larger proportion of the
rakyat will use it.
"The goal is to have subsidies targeted and more focused at those who need it, such as the lower income and middle income groups, and giving a choice to the rich on what petrol they want to fill in their tank," said Datuk Shahrir Samad, the minister.
High-performance models like the Civic Type-R, Swift Sport and Lancer Evo need high octane fuel (RON98) but such cars are sold in very small numbers in Malaysia
There are often misconceptions with regard to the technical aspects of high and low octane fuel so here's what it is all about. Firstly, if your car's engine is tuned and recommended by the manufacturer for a minimum of RON92, then you are not going to get increased performance using RON97 or RON99. Just because the octane is higher does not give you more 'power' because it does not work like that in combustion.
Latest Honda CR-V, a SUV, can run on RON92 without any problem
The second thing is that octane requirements are not dependent on bodystyles so it is incorrect that 'SUVs run on higher octane' (which appeared in the news reports). As mentioned earlier, the Honda CR-V has been tuned to run on RON92 and a number of other SUVs can also use this fuel. It is all dependent on the manufacturer and the engine and even then, large engines can also run on low octane. The Ford Escape 3.0 V6, for example, is tuned for RON92.
There was also mention that RON95 will be of a 'lower quality' than RON97 and this is probably what is causing concern among motorists now, as evident in the discussions in our MTM Forum. The quality will be lower only if the additive package is minimal compared to the higher octane fuel which petrol companies have typically promoted more strongly. However, under the new plan, if RON95 becomes the lower grade and it is intended for the majority of motorists, it would be irresponsible of the petroleum companies (with the exception of Chevron) to do what they have been doing with their RON92 petrol, ie putting in little or no additives. If RON95 becomes the high-volume fuel in Malaysia, then it would only be logical that it would get a superior additive package.
The powerful FSI engine of the VW Group requires RON98 petrol but if a lower octane is used, its knock sensors will adjust the ignition timing to prevent improper combustion
Knock sensors which are attached to the engine and detect knocking
Having cleared away some myths, let's now look at some issues concerning the use of petrol which is of an unsuitable octane for the engine. If the engine is tuned to run with RON93, then you cannot use a number lower so RON92 is out and you would have to use RON97 (at this time). If you use RON92, a condition called 'pinking' or 'knocking' is likely to occur and this is the result of improper combustion. The condition gives off a sound like marbles rolling inside the engine, especially if you are going uphill. If it happens long enough and often enough, damage can occur to the engine because those are sounds of unwanted explosions inside the combustion chambers. In some cases, these explosions occur as the piston is rising and create a downward force on the piston. Loss of power also results during pinking.
Using the right fuel octane or a higher one prevents this condition. In more expensive engines, there are also devices called knock sensors which are like little microphones that detect knocking. When such a condition is detected, the engine control unit (ECU) will adjust the ignition timing to compensate. This usually eliminates the knocking but there will also be slight reduction in power output.
However, a Shell engineer did once make a case for using an octane higher than recommended, mainly for older engines. His explanation was that with older engines, the accumulation of deposits inside the engine can cause a slight increase in the compression ratio and though not always the case, a higher compression ratio usually requires higher octane fuel. This being the case, if the compression ratio in an older engine gets higher, then there is a remote possibility that pinking can occur so it may be better to use the higher octane petrol even if a lower one is recommended.
How would you know what is the right RON for your engine? This information is usually stated in the Owner's Manual and the minimum RON is specified. There may also be a sticker on the fuel lid cover which indicates the correct RON. What's important is that you do not use an octane lower than that specified. When in doubt and the manufacturer or local representative cannot help, then the safest bet is to use the highest octane possible which, at this time, is RON97. Only a small number of models would need a higher octane than that and quite likely, they would have knock sensors in their engines.
The inside of the fuel lid on many cars will have a sticker to indicate the correct petrol octane required
There are also 'octane boosters' available in some stores and these are additives which are added to the fuel by pouring into the fuel tank. Engineers in oil companies usually avoid commenting on such additives as they feel that there is a possibility that adding something else could upset the optimised formulation of their petrol and instead reduce benefits. There is also the possibility that these additives may leave behind deposits after combustion, an undesirable by-product that will affect performance in the long run. So it's up to you to use them if you are convinced that there are benefits to be gained.
While on the subject of petrol, it would also be useful to make it very clear that unleaded fuel is no longer sold at the pumps in Malaysian stations. A law was passed some ten years ago on this but it seems that many motorists still believe that Regular RON92 petrol contains lead. This confusion could be due to lack of initiative by some petrol companies in removing stickers on the pumps which used to specify that they were dispensing leaded fuel or simply ignorance of facts.
The introduction of unleaded petrol (ULP) occurred in the early 1990s in Malaysia as a prelude to the requirement for petrol engines to have catalytic converters. Lead was a component in petrol for decades but it is poisonous and decades of spewing tons of fumes into the atmosphere meant that the air became unhealthy. So lead was phased out and it was also necessary to do so because the catalytic converter, which chemically removes most of the toxic emissions in exhaust gases, will get damaged by lead.
Older nozzle (top) with larger diameter for pumps which dispensed leaded fuel and the one with a narrower diameter for unleaded fuel
During the transitional period up to the mid-1990s, leaded petrol was sold alongside ULP because cars with very old engines needed the lead to protect the valves from wearing out (hardened valve seats were introduced to address this issue when ULP was used). Leaded petrol was confined to RON92 and in most cases, it had a red dye to make it more obvious.
Another measure to prevent motorists from accidentally filling leaded petrol was the industry-wide adoption of different nozzle sizes. In collaboration with carmakers, a smaller opening was provided for the fuel tank pipes in newer cars with catalytic converters. The petrol companies installed nozzles on ULP pumps with a smaller diameter while maintaining the larger diameter nozzles for leaded petrol pumps. In this way, it was almost impossible for a motorist to accidentally pump in leaded petrol because the nozzle would not go in.
When the Malaysian government finally phased out leaded petrol and RON92 was also ULP, the replacement of nozzles was not done speedily and even as recently as a year ago, there were stations still having the larger diameter nozzles on their RON92 pumps. Because of the perceived 'lack of demand', the petrol companies probably saw no urgent need to make the change, again influencing statistics of the true demand for this grade of petrol.
As for diesel fuel, well, that's another matter altogether and the car companies as well as many motorists are waiting for the government to actually upgrade the standards rather than talking about 'going to do it' year after year.
Cheers
