Wednesday, 26 August 2009

BIG question over RON 95 on old Proton cars

Seems that many petrol stations are now selling the RON 95 petrol ahead of the 1 Sep 2009 deadline. I know that my Avanza can run on this petrol because I've even run around Penang on RON 92 in the past. But my Proton Iswara? There are tens of thousands of old carburetor-fitted Proton cars on the roads but I don't see the manufacturer reassuring Proton car owners on their ability to use this fuel.

7 comments:

stephen said...

Your old Iswara was actually designed for RON92 petrol or higher so it will run as well on 95 petrol.Feeding it with petrol of a higher RON number will just burn a hole in the pocket without any performance gain for your car.
The switch to 95 petrol is because new cars nowadays require this minimum grade of petrol.Thank goodness, we still have 92 petrol over here as my van can run on it- saves me money!

vinnan said...

Stephen,

The proton Iswara MUST run on a minimum of RON 95 petrol. Ironically newer Japanese cars such as the Avanza and Vios are actually tuned for RON 90 and RON 91 petrol respectively. It is a myth that 'new' cars MUST run on a minimum of RON 95 petrol. As a matter of fact, many new cars have knock sensors which allows the engine to run on a lower RON petrol than what the engine was actually tuned for.

In other words the RON requirement of an engine is based on the ignition timing set by the manufacturers of the car and the presence of knock sensors which allows the engine to run on a wide petrol RON range.

stephen said...

Vinnan,i have to disagree.The mitsu engine in the iswara is a basic carb engine designed long ago for low RON numbers prevalent at the time and lower emission standards.Its almost the same engine found in early hyundais.The reason why some people claim they need a higher RON for their car is because their engine is in need of an serious overhaul!
The newer cars though equipped with knock sensors and unified ECUs do have operating and performance limitations built in ,some of it ,generic to the country that it is meant for.The cars that we see on our shores have engines tuned for ron95 and above.You must understand that using a lower RON will result in a performance decrement and the manufacturer will specify the lowest possible before it falls off the curve.Conversely, using a higher RON does not necessarily result in better performance if the engine mapping unit does not recognise it.
Nissan does mention the expected power with different RON numbers and most manufacturers will tell you to use RON92 only as a last resort and also to modify your driving style.

vinnan said...

Stephen,

If you are referring to the Orion engines it may well be true that the Proton saga need nothing higher than RON 92 to run properly. The Iswara Megavalve engine especially the 1.3 variant which has a higher compression ratio than the 1.5 variant WILL need RON 95 or higher. I experimented on my new Iswara which I bought in 1995 and RON 92 was a no no. Silly me I thought the RON 97 requirement stated on the petrol tank cover was just for show.

stephen said...

I must confess that the only proton cars that I have driven are all rented whenever I'm down in Pg.From Saga to Iswara to Wira and Waja for many years.But from my experience,you can run 92 on cars without the sticker on the filler cover just like the jap cars.Since SS was using 92 on his Iswara,then 95 shouldn't be an issue.The petrol station where you fill up also plays a role in the performance of your engine.Cheers

m.p.c.lean said...

hi all...come across this while looking for the same answer...
i'm driving iswara with the sticker on the cover...
from the discussion above, does that mean i can ignore the sticker and pump RON 95?

SeeChew said...

I tried on my iswara and it was a nightmare...no power and for a few time the engine going to die....

so...plz plz plz never ignore the sticker on ur cover.