And how the heck does fuel damage the throttle body? How can the fuel damage any parts that it does not come into direct contact? Might as well say that by just driving the car on the road the paint is being worn off by using RON95 petrol.

Yeap.. something else is wrong the TS car.. and not the fuel.

This post has been edited by sleepwalker: May 21 2012, 11:50 PM

First of all, it is not all about the static compression ratio. Compression ratio alone does not determine whether the engine pings or not. 4G63 compression ratio goes from 7.8 to 8.8:1 from the oldest to the newest and final batch of the 4G63 in the EVO 9. Subaru EJ20 maintained at 8.5:1.

It's all about the engine tuning. To squeeze more power out of the 2L engines, the Japs had to put very aggresive tuning and need to run it on RON100. They didn't make it run on RON100 just because they had RON100 fuel. Since the Japs don't give a damn about emissions control, they can tune it hard and run RON100 and spew shit out of the exhaust without anybody bothering them.

However, on export models and with strict emissions controls in US/UK, they had to use the EJ25 (2.5L) to produce the same power as 2.0L due to the less aggressive tuning and those engines are made to work with RON95 and below.

In Malaysia, the grey importers bring in JDMs and will ping when they use RON95. As much as the ECU wants to retard the settings, by default, it will always try to revert back to original aggressive programming and the engine will keep pinging. Those who purchased the export models from local distributor like Motor Image, can run their WRX on RON95 without any issue.

I run my UK model WRX on RON95 without any pinging since it was made to run at RON95 for export models.

We get our petrol from overseas too since we don't refine them all in Malaysia. We export crude oil but import refined petrol. I don't find anything wrong with our RON95 even with my turbocharged engine. What's wrong with your car?

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Added on July 31, 2012, 6:35 pmWhy use RON97 when the car does not need it? Driving a sports car does not mean it needs RON97 unless you get a grey import JDM model. My car is made for a country that does not sell RON100 and runs on RON95 as per the owners manual. All new sports cars nowadays exist in both JDM and export models and both are tuned differently. Gone are the days of people driving an EVO 6 in UK/US trying to hunt down petrol stations that sells premium RON 98.

This post has been edited by sleepwalker: Jul 31 2012, 06:35 PM

Not just don't know how car works.. just don't know who things work.. period. Common sense.. is so rare nowadays that it should not be called 'common' anymore.

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Added on August 1, 2012, 8:19 amThe only problem you get from using the fuel with a RON rating that is too low for your engine would be detonation/pinging/knocking. The result of that in the long run would be damage to your piston/conrod and possibly crankshaft as these are the only things which would be directly affected by detonation.

Anything else that spoils is not related to the fuel. Any good mechanic can tell you that. Your mech is just not good enough if he blames your spoiling air con to bad fuel. That is like saying the wrong tyre caused your windscreen to break. It has no relations whatsoever.

This post has been edited by sleepwalker: Aug 1 2012, 08:19 AM

He's asking how you come to the conclusion that compression ratio directly determines the RON usage. The site does not explain that because compression ratio is just a static component measured at TDC. Static compression ratio alone does not determine the RON usage.

Ignition timing plays a bigger part as the more aggressive the timing, the higher the RON is required to prevent detonation even though there is no change to the static compression ratio.

As for CPS lower compression ratio, that is not due to reduced timing as stated by you.



Every engine can only have 1 static compression ratio as that is determined by the shape of the piston. In the CFE, the piston is changed to reduce the compression ratio from 10.1 to 8.9 without changing the length of the conrods. Ignition timing DOES NOT change static compression ratios. Therefore the campro CFE static compression ratio is 8.9 and not a variable 8.9 to 10.1. THis is static compression ratios we are talking about, not dynamic. That would be another story and another topic.

This post has been edited by sleepwalker: Aug 2 2012, 12:51 PM

Then you are talking about dynamic compression, not static compression anymore. Just like how a forced induced engine has a much higher dynamic compression ratio even though it has a lower static compression due to the fact that more air and fuel is forced into the combustion chamber. However, this does not change the fact that the STATIC compression ratio remains the same throughout the whole process.

It is not a trick. It is your lack of understanding what Static and Dynamic compression ratios are. You do not change static compression ratios by changing valve timing and lift duration.

Yes but we are not talking about those engines are we? The word STATIC means non-changing. If an engine has changing ratios, they'd most probably call it..Variable Compression ratio (yes thank you captain obvious..)

And your reference again to otto cycle engine is still not related to STATIC compression ratios. That is dynamic compression ratios.

Please understand the fact that the calculation of the static compression ratio comes from simple volume mathematics. Don't look at the formula in wiki as that would confuse you into thinking that CRs are complicated stuff. It is just a simple volume of the whole cylinder when the piston is at BDC (bottom dead center) plus the volume between the piston and engine head at TDC divided by that same volume again at TDC.

Once you understand that, you will realise that no matter what you do with cams/lifts/valves/duration/etc etc, you will never change the Static CR. Confuse yourself Static CR with Dynamic CR.

He wasn't replying to you and he wasn't talking about his car or your car. If you had read this topic from the start instead in jumping in half way you would know what he was referring to about the 'air con' not cold part.

Can you guys please quote who you are replying too as you guys are all getting confused jumping in halfway into a topic.?

This post has been edited by sleepwalker: Aug 2 2012, 05:50 PM

Unfortunately, for most road cars, the ECU is only self adapting downwards. It will not increase the aggressiveness of the ECU if you give it better fuel but it will retard to protect itself if there is something wrong with the fuel.

Therefore pumping better fuel into an ECU programmed for RON95 will not give you increased performance. I have tested this with my own car. If I don't change the baseline settings and leave it at OEM factory, even if I pump RON 97, it won't increase the aggressiveness on its own. Human intervention is required.

The only way to increase performance is to change the baseline settings in the ECU for a more aggressive setting. I'd pump RON 97 and keep increasing the aggressiveness of the ECU until it starts to retard on it's own and then download the logs to monitor (I don't like driving with the notebook connected to the OBDII port) and fine tune the settings. That was when I was a noob until I found the hundreds of ECU map available that were dyno tested and I could download them for free into my engine. Now no not much testing needed. Just pick and choose the map I want.

This is the reason why most cars don't get a performance boost when using better fuels and only retards on bad fuel as the ECU is made to tune down and not up.

It will adjust downwards but I didn't say it will stay there permanently. It will adjust back to factory default but most will not go above that.

It most probably wouldn't even affect the engine. Unless you have a high tuned or high strung engine, the lower RON will not even affect it as the ECU mappings might be so sedate that a lower RON will not cause any pinging at all. Highly tuned engines are more sensitive to RON levels than those engines you find in normal cars.

Did you check your fuel filter? Engine choking are usually the signs of a clogged fuel filter and by putting something like a fuel injector cleaner, you are actually not just cleaning the injectors, you are also cleaning some of the gunk collected on the fuel filter. I have seen this happen many times and the symptoms come back after a while unless the fuel filter is changed. Always use a fuel injector cleaner only after you have changed the fuel filter, otherwise the injector cleaner has to go though a dirty filter and end up cleaning the filter instead of the injectors.

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Added on October 23, 2012, 4:31 pmWe are not really talking about different types of fuel nor are we attempting to make a list of it. There is another topic for that under the fuel consumption topic. Now that RON91 is no longer available (if I wasn't mistaken, it was 92 back then, not 91), we'd stick to the this rather old topic of RON 95/97.

This post has been edited by sleepwalker: Oct 23 2012, 04:33 PM

We had RON 92 a while back. The rest of the world has RON 92. Just that RON 92 will complicate the subsidy. Price difference would only be a few cents and not much of a savings. Since our petrol is subsidised, there cannot be any competition in pricing unlike other countries with petrol kiosk selling RON 92 at much cheaper rate to attract customers. RON 92 would also hamper logistics.

You have that option in Australia.. cheap days.. cheap outskirt kiosk.. where they can price the fuel according to location and availability of stocks.. and of course oil price.

There's no such option here and to pump RON 97 just means that somebody else is enjoying our subsidy.

What has subsidy and economics got to do with your reference to fuel industry R&D? You already terpesong topic.

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Added on October 23, 2012, 5:54 pmOutskirts.. not outback.. wasn't referring to such rural areas. Outskirts of town instead of town center. Not outback country.

This post has been edited by sleepwalker: Oct 23 2012, 05:54 PM

Unfortunately the EURO standards are more for emissions control than outright performance. I'm more interested in the additional additives that they have put in for the new fuel but I have yet to check it out.

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Added on October 23, 2012, 6:11 pmYes but that has nothing to do with R&D (you terpesong to R&D). It's all economics. Fuel stations will have to build additional holding tanks. Tankers will have to transport more fuel types. Not worth the few cents of savings to the public. Even now, stations serving RON97 is beginning to disappear but I'm sure they have some form of 'agreement' (gun to their head) with the gov that each brand must have XX amount of RON 97.

Therefore, it is not viable to provide RON92 in a subsidised market. Nothing to do with R&D.

This post has been edited by sleepwalker: Oct 23 2012, 06:11 PM

So when did some become all? I didn't say ALL cars waste on RON 97. You are the only one who did. It is a waste on most cars that is not tuned to use anything higher than 95. Most is not all. Tell me which country you know that only sells ONE type of fuel that is not under military rule or international sanctions? If you don't understand the economics here, don't bother discussing. This is getting pointless.

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Added on October 23, 2012, 9:16 pmAgain, learn to read and understand. We were no longer talking about RON 97. We were talking about EURO 3 BHP RON 95 and RON 97. Nothing said that RON 97 is cleaner and will make engine last longer.

Do not take quotes out of context if you have no idea what we are talking about.

This post has been edited by sleepwalker: Oct 23 2012, 09:16 PM

100K km is a common fuel filter replacement schedule but some manufacturer's might change it early. At 90k km I can say its pretty much clogged up by then if it has not been changed before.