ClubCJ - The CJ Lancer Club

Since I bought the car from new I thought I would run RON98 fuel from day 1.

Is anyone else doing the same thing? If so what sort of mileage are you getting and do you think it makes much of a difference runnng the premium over the regular unleaded?

I run unleaded in my Aspire and that is fine if the car is standard.

Putting RON98 will not improve any performance. It is just wasting your money.

I plan a few changes to the engine and it will should run better on RON98 then.

I have recently started to run my VRX on 98RON since i got it tweaked a little,it seems to run a little better and fuel economy is quite good.
Even before the recent induction and tuning mods i got it down to 6.1L/100Kms on a trip to Ballina,
I'm driving tp Coffs Harbour soon....I'll see how it goes then.

you can get more economy from higher RON fuel, slightly better torque on hills.. more BTU = more torque = less throttle = more range...

its a proven fact

notice before anyone responds, I never stated that its financially more economical though...

tryg wrote:you can get more economy from higher RON fuel, slightly better torque on hills.. more BTU = more torque = less throttle = more range...

its a proven fact

Yes proven on performance engines and proven to be very very little or none on normal engines built for normal unleaded!

i generally either get bp premium or the shell equivalent.

i get between 650-700kms, mostly all freeway driveway, and thats pretty much a tank a week for me.

have used the lower quality stuff and found to get around 600kms a tank, so make of that what you will.

maybe your car is a dud Aspir3... I get more range and better torque with few mods... might not save much for the benefits, but happier car... closer to optimal, than knocking....

I have proven this fact too many times to count, especially with bikes on a bike dyno... with zero mods just fuel change and 20mins for computer to correct.. higher torque figures...

how many RACQ tests do you have to read before its believed..

Our cars are sophisticated with Knock sensors and it knows if you runa high or low RON fuel... The Engine ECU actually has timing, ignition and fuel ratio maps for both High and Low Octane fuels...

Allows more timing etc for higher RON fuel

I've only ever had BP Ultimate in my car. Except during a shortage once I put $20 of Caltex Vortex98 to get me to a BP that had Ultimate in stock.

Hi Adrian,
you say:

The Engine ECU actually has timing, ignition and fuel ratio maps for both High and Low Octane fuels...
Allows more timing etc for higher RON fuel

If this is correct (I have no basis to doubt you) then more timing is definitley going to result in higher power outputs, albeit only slight depending on the amont of timming increase.

It would be interesting to know exactly how much the ECU alters the timing according to Fuel RON in use. Could you please post the ECU timing changes Adrian.

Anway our great politicians who do thier best to run this country (into the ground) re-announced last week that as of June/July 2011, Unleaded fuel will no longer be available.
Resulting in two fuel choices only: Premium Unleaded and E10. Fuel prices at my local last week showed unleaded @ $1.19 and Pemium @ $1.39 = 20c difference.

I wonder how the pricing structure will pan out next year when only two fuels will be on offer. Remember the Govt wants to promote E10, so if we apply the governments time and proven methods of extracting the Tax Payers Dollar, they will price increase Premium beyond affordabilty and thus allow the price of E10 to creep-up so as to appear competitive. Net Result for both the Govt (fuel tax) and the Fuel Companies (profit).

Cheers: Sam

i have tried it before and noticed nothing.

a few weeks back they done this test on Fifth Gear, and each test they drained the tank, filled it with new fuel and reset the ECU and the most extra HP they got was about 5hp i think. but the main points they made was its not worth it, and if you do you HAVE to reset the ECU.

I usually run regular unleaded and fill it up with premium once a month.

Car doesnt go any faster, nor do i get any more fuel economy (never checked) but the car does seem to run a little smoother...

Have always run Caltex Premium (partner works for woolworths so get staff discount). On the odd occasion we have put a a splash of regular in the car we have noticed it doesn't run as smooth and seems to be less willing at lower rpm.

Sounds reasonable what Adrian said about the ecu changing maps depending on fuel type and adjusting timing etc... as that can explain the increased responsiveness at lower rpm.

That's just my two cents worth. Each to their own tho I suppose.

Always used 98RON.
Prefer the BP Ultimate.
It is the purest of the 98 RON (Got an article on it, will post later)

its not just our car that adjusts mapping to knock sensor output, its just about all (unless you have a car made in India or something)... Even my motorcycle from 2004 has it...

Cars (and bikes) have a plethora of sensors that contribute to the fuel mapping table. Some have, pre- and post- narrowband O2 sensors, knock sensors, absolute atm pressure sensors, airflow metering, air inlet temp, etc.. all this can marginally change the mapping...

There are gains, yes they are small. I get 60km extra on RON98 fuel, highway driving. Or, about 40km extra-urban. Also, my G TAC Pro recorded a faster overall 0-100km/h time, and increased torque, from 0.41G full-acceleration testing, to 0.43G on 98RON.

You dont have to reset ECU, they modify to suit fuel type after about 20mins of running, this is what my 2004 Moto Guzzi does. I am sure the Lancer is even more sophisticated... I have opened my ECU tabling on the Guzzi to read the mapping differences on both types of fuel, it is able to manifest 5% changes without reaching the prescribed limit of the cell. Anything higher would require a stand-alone fuel management computer, such as a PowerCommander... Cars work no differently.