Firstly, are you refering to high performance cars? If not, which car in particular are you refering to? The topic of discussion i believe is normal day to day passenger cars. Secondly, is the car designed for Ron 95 or Ron 97?

all cars has a range of octane rating that the engine can consume.
eg a vios can go as low as 93. but it will perform better at 95, or 97.
the "car designed for Ron XX" figure is the lowest it can go without dying on u

This post has been edited by masao343: Oct 23 2012, 11:56 AM

http://www.youtube.com/watch?v=QRt-Iw8FTbg...outu.be&t=30m9s

This post has been edited by torreto: Oct 23 2012, 11:57 AM

How do you know a car specified as Ron 93 compatible will perform better using Ron 97? We're not saying that cars cannot operate on higher octane fuels. The question here is:

1) Is there an actual significant increase in power and performance using normal Ron 97 fuel in a car specified for Ron 95?
2) Does this difference (if any) warrant the extra price we're paying for Ron 97 fuel long term?

What do you think?

This post has been edited by cybermaster98: Oct 23 2012, 01:15 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.

Does that mean, god forbid, if I ever pour RON 92 into my engine, it will run on a retarded timing that is suitable for 92 even if I pump 95 or 97 later?

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.

I see, thanks for clarifying

Sorry if my post is too late, as I was just looking around the forum, I stumbled across this thread and I would like to share that my car after 2 years of using Petronas RON95, is choking actually. Went to the service center, they clean the throttle body but there is still intermittent choking.

I don't really believe in additives, but somehow just a few weeks ago I bought a bottle of STP Petrol Injector cleaner and somehow it was marvellous after a few days of running, immediately the engine became smoother and quiet.

But RON97 being gold prices, now using BHP95 and it seems okay, I think most of our RON95 petrol builts up carbon and such.

Agree injector cleaners help a lot, I experienced a big difference when starting my Mitsubishi. engine so smooth after service. no more rough idling.

Food for thought my 2004 Subaru runs smoother on Mobil RON91. People should include a list of what fuel is best for their cars.

Having owned a few cars, I have avoided using Shell. I find Caltex and BHP generally are ok.

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

if ron92,ron95 and ron 97 doens't give any difference and didnt cause damages to engine .. should just intro ron92 and we all can get cheaper fuel ..

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.

Do you think the new BHP Ron 95 Euro 3 fuel will be better than the current Euro 2 fuel offered by other competitors?

Here's my take, use RON95 if you know it is fresh from the oven, but I don't know if this is available info. Most probably not.

I drive a conti TC car and recommended fuel is RON 95 but being a cheap ******* like I always am, i buy fuel on cheap days, cheap for a reason, assuming service station still has the old batch. Car engine management system will always detune with old RON95 batch but good I have ECU overide device so error codes not a problem.

Fact is where I am RON98 is the better fuel....no brainer. For now, I have a refuelling strategy, half tank for RON95 and RON98 for full tank.

Hope this helps.

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.

mean we cannot use the cheapest fuel and the more expensive fuel .. as the cheap 1 no good for our country economy? and the expensive 1 just waste of money .. if that so .. the fuel industry R & D should close their office and continue to use ron95 till the end ?

rural areas are actually dearer due to logistic issues...but yes very hard to troubleshoot problems like this. Best to run higher octane fuel for performance cars as much as you can.

RON95 on normal cars is not a problem except for Shell that you may experience a small drop in performance.

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

ai i though u are the one who say ron 92 subsidy only difference by few cent and will hamper logistic ??