Fuel quality

[Tannin]

The reason guzzla has never noticed any difference between brands is because there isn't any difference between brands. (Well, none that you can pick this side of professional-grade test gear, and probably none worth mentioning then either.)

But there is, of course, a difference betweenb different types of petrol. Premium fuel Shell Ultra (just as one example, there are equivilents in all the other brands) will take you measurably further on a tank, and makes most modern cars a litle more nippy. The performance difference is very small and hard to measure, but the economy difference is quite significant and very easy to measure. 98RON like Ultra consistently takes you further on each tankful.

Of course, it costs more too, so you have to trade off the cost against the benefit. You can't give a hard and fast rule like "95 RON is the overall best for economy" because the price difference changes all the time. One day the 98 octane will be the best buy (costs a bit more but takes you further), the next weekprices change and you are best to get the cheapest E10 ethanol blend 'cause it's quite a lot cheaper than standard 91 and you get more miles per dollar.

So:

• if you mostly care about performance, buy expensive 98 RON.
• if you mostly care about getting long range from a tank, always buy 98 RON.
• if you mostly care about economy, buy whichever one is giving the best bang per buck at the time - this could be any type at all - E10, 91, 95, or 98, all depending on the prices.
• if you mostly care about doing your little bit to minimise global warming damage, buy E10 because then only 90% of your fuel is fossil-based and the other 10% is renewable and does no harm cause it grows again next year and re-absorbs all the carbon in it. (Technically, it's a bit less than 10% because there is usually some small amount of fossil fuel used in the manufacture and transport of the ethanol. Call it 8% or 9% at a guess. Still a lot better than 0% any way you slice it.)

In a perfect world, you would have careful measurements and a smartphone app to tell you that E10 at $1.29 is cheaper per mile than 95RON at $1.36 but 98 RON at $1.39 is betterthnan either (just example numbers, don't quote me on those). But in the real orld, you just look at the prices and make your best educated guess.

Rules of thumb:

• 5c extra per litre for a step upgrade (91 to 95 or 95 to 98) is worth paying.
• 10c extra per litre for a step upgrade is not worth paying.
• but these rules ^ should really be expressed in percentage terms, so when petrol is very dear ($1.94 a litre in an outback town, for example) the 10c is worth paying. Besides, out there you probably need the extra range. And if petrol is very cheap, adjust the other way.
  Territory
• E10 is usually either equal best value or outright best value, but watch those price differences! Sometimes E10 is only 1c or so less than 91 RON, which makes it cost more per kilometre overall. So you can't just buy E10 every time and be sure you are getting best value.
• 95 RON tends to be the most expensive per kilometre - you are only getting a one-step economy upgrade but the price difference can be large. Of course, sometimes it is the best value. Stay alert!
• 98 RON can be very dear but it's often not much more than 95 RON and worth the 2c or 3c difference. As always, check each time.

Me, I like to use E10 wherever I can for envionmental reasons, but I'm damned if I'll pay overs for it, and you can't get it everywhere, so I wind up using E10 a lot, but also 98 or 91, and sometimes even 95 if the price is right.

[Rally]

I think they use MON, not RON. Knowing the MON is more important than knowing the RON.

Originally Posted by d_generate

I was told United/Liberty/Peak fuel is imported from Singapore, not too sure how accurate that is, we haven't got E85 or 100ron over here yet as far as I know, I'd love some 100 in the V3 STI Liberty as that's what the JDM computer is tuned to, for that matter the offroader has a JDM RA V2 STI computer in it too.

U.S. uses a totally different RON system to us so their fuels are actually much better than most Aussies think.

[OutbackOiler]

Unfortunately it's not as simple as what has been explained either when it comes to 98 octane fuel it also has to be fresh, if you buy 98 octane from a low turn over station you are wasting your money as it goes stale quickly also if you don't go through a tank a week 98 octane is a waste of money. For example in Brisbane all guys who raced on weekends would fill up at one station, the station they knew always had the freshest fuel. This is a fact, not speculation don't use 98 octane unless you do the kilometres, 95 will be fine. When I am around town I use 95, when I am doing long trips I use 98. It's a bit like cooper tyres, they are good for 80000km if you do that in a few years great, but if you only do 10000km a year the tyre will have gone off before it wears out

One of the reasons it has taken so long for Australia to catch up with diesel cars is because our quality of diesel is horrible and it needed to be fixed up a bit to handle European motors as they would clog very quickly.

As for E10 make sure your car can take it, if you have anything other than a designated ethanol tolerant car, call the dealer to make sure it's ok. For example VY commodores are a no no for E10, it eats the fuel pumps.

[guzzla]

Originally Posted by Tannin

• E10 is usually either equal best value or outright best value, but watch those price differences! Sometimes E10 is only 1c or so less than 91 RON, which makes it cost more per kilometre overall. So you can't just buy E10 every time and be sure you are getting best value.
• 95 RON tends to be the most expensive per kilometre - you are only getting a one-step economy upgrade but the price difference can be large. Of course, sometimes it is the best value. Stay alert!
• 98 RON can be very dear but it's often not much more than 95 RON and worth the 2c or 3c difference. As always, check each time

In all my travels around Australia I have never seen 98 cost any less than 5c more than 95 and 200,000km + of accurate records with my XT shows there is no advantage in using 98. Many times I have tried 98 for maybe half a dozen tank fulls and then reverted to 95 and over the same trips in the same conditions at the same speeds the results are consistently the same. However the few times I have been forced to use E10 there has been an iincrease of around 10% in consumption. I'm determined to never use it again.

[OutbackOiler]

I have also stumbled across a product quite a few years ago now called fuel doctor. When I first tried it I had a 95 VW Transporter diesel, it had about 180000km on the clock and was not doing so well on fuel consumption at this stage (I was a courier in Brisbane at this time) I was getting around 15-16 litres per 100km at the time. As I did around 1500km per week the results were very noticeable, within the first week my consumption went to 10 litres per 100km whether I was loaded or not and even better on long highway hauls. It is meant to clean the injectors while you drive and will eliminate water from your tank, if you have a diesel it will eliminate any chance of diesel bug plus it is meant to de-coke your engine slowly without having chunks fall off. I always use it petrol or diesel and if I get caught without the ability to get premium unleaded, this will boost the performance of 91ron. I use it and swear by it.

[lucaswheat]

I used 98 for my first tank and E10 for my second and third tanks. I got better economy for the two E10 tanks (by about 20%) but the Check Engine light has been coming on in the mornings - goes away after about a minute of driving.

I'm going to try two tanks of 98 and see what happens to the Engine light. I have a feeling that the E10 is the cause from reading other forums on ethanol based fuel.

[lucaswheat]

Then again - it could be the ECU was reset when I was installing the stereo and unplugged the batter a couple of times...

[NachaLuva]

Originally Posted by lucaswheat

Then again - it could be the ECU was reset when I was installing the stereo and unplugged the batter a couple of times...

haha that could be it

Originally Posted by OutbackOiler

I have also stumbled across a product quite a few years ago now called fuel doctor.
...
It is meant to clean the injectors while you drive and will eliminate water from your tank, if you have a diesel it will eliminate any chance of diesel bug plus it is meant to de-coke your engine slowly without having chunks fall off. I always use it petrol or diesel and if I get caught without the ability to get premium unleaded, this will boost the performance of 91ron. I use it and swear by it.

Just looked at their website...might have to give it a try...

Plus they tested it on a Brumby!

Go to Fuel Doctor, then "tech talk" then click "more" under "Is Fuel Doctor economical?"... their own Brumby bought in 1992 & now at 196,750kms

[nipper]

Originally Posted by tempo

I did some research on the net about gasoline:

1)Basicly all fuel are the same and coming from same "pipe" to every company. D
2) Differance is only chemicals that company using
3) Chip gas stations using minimum additives just to by comply with goverment reqiuarements
4) Expensive gas stations using maximum and best additives
5) Additives or chemicals are detergents to keep fuel system clean
5) On the top of the list Chevron Shell BP
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So for my understanding you can buy chippest gasolne and just use once a while special additives?

If I remeber correctly, there are only three real "brands" of gasoline coming out of three different companies refiners. From there chemicals are added to get the product that each fuel company brands.

Hess, Exxon, Chevron and Volero I know make it for themselves, I dont know about the others. Wikipedia has a list.

List of additves http://en.wikipedia.org/wiki/List_of_gasoline_additives

About 7 years ago the auto MFG's got together and threatened to set a std for fuel quality in the US as cheap fuels were starting to damage fuel injectors and causing warrenty issues. They were going to certify some brands and not others. that caused the Gas brands to clean up their acts.

Interesting Read http://www.petrostrategies.org/Learn...ry_players.htm

Dont knock the additives, some are much better then others. Also too much of one additive may give your car heartburn. Cheap brands dont really care where they buy it from so there may be no consistancy in the blend. They also get "spoiled" batches, where the fuel meets federal regulation but may not meet the brand names requirements for the blend. Also bad fuels do get through, and a common one is fuel with too much sulfur. This can screw up fuel senders or worse.