What is the best petrol brand for the RX8. ie. bang for buck ?
 

I've heard various opinions in the last week amongst work colleagues on different feul grades and which are best for your type of car.

I do know that there are lower cost refineries in Asia distributing lower grade feul to various retailers in Aust. Clearly Woolies, or Safeway in Victoria and Coles Express (with Shell) are most competitive on pricing. This is my experience anyway ( live in Camberwell ) If you fill up on a Wed pm or Thurs am, then you are most likely going to get lowest price for the week.

I heard that Safeway petrol is effectively Caltex, which you would expect to be a pretty safe and high grade pertol. Coles Express are Shell petrol ...once again should be pretty high grade.

I've also used the BP Ultimate, 98 Octane, which is also the most expensive. ie. usually around $1.05 / ltr.

I have not noticed any significant differences in ride quality or performance when trying different premium feul types.

What's your experience ... knowledge on this topic of feul grade differences and performance changes .... impact on car over time ??

I always run BP Ultimate as a rule. Except in "emergencies".

I used to nearly always / often use Caltex Vortex until I got a bad tankful (A little bit of petrol, a lot of water), and they f'cked me around until I got some legal representation. Even then they didn't do anything to show me any goodwill, so I don't use their product on principle.

BTW - I'm intrigued by your question regarding differences in ride quality due to fuels.

Cheers,
Hymee.

Hi Thommo,

Same as Hymee with Ulimate whenever possible.

I think your point about the effect on a car "over time" is a good one. From an engineering point of view, lower quality fuel is usually quoted as potentially causing more internal problems (or whatever) due to poorer running, but how big a factor this is for a given fuel or engine is pretty much impossible to assess at an owner level.

You would probably need to be pretty sensitive to notice the power difference gained by a few extra octane (although I have heard many people claim that their car did run smoother and nippier on the more expensive fuel).

If you had a test bed, a few engines, and a few thousand hours to spare you should be able to pick the difference internally, but whether the improvements seen with the pricier stuff would justify the extra fuel cost is anyone's guess. From memory, the differences come in the areas of poorer running, more deposits, more wear and burning out of components etc. Big or small differences - who knows! :eek:

But does paying for a Ferrari justify it being ten times the price of a Hyundai or whatever? Both will do the maximum speed limit and get you there. With cars each little bit of extra goodness usually costs more proportionally to get. :)

The way I look at it is I buy the best quality fuel and oil I can find, and I don't worry too much about the price.

If I pay 5c extra a litre and put in 40 litres it's only cost me an extra $2.00. I can afford $2.00.

If I coudn't afford to pay a little more for higher octane fuel, top grade oil (and things like paying $400 + for a new tyre) then I wouldn't have bought a car worth over $60,000 in the first place. Sounds like a yuppie kind of attitude, but I think it makes engineering sense too. :)

Cheers,

Chris

I think some input from somebody in the oil industry would be helpful here. With the shrinking number of refineries in Australia, it would not surprise me if I were told that Ultimate or Optimax did not come out of the respective brand-owner's refineries. Custom manufacture might be occurring, or simply Shell petrol could be going into a BP servo's tanks for instance.

If this is happening, it makes a mockery out of being too prescriptive about the merits of a particular brand.

I'm with you labrat. I heard that optimax and ultimate bith come from the shell refinery. I think mobil 98 octane is different though.

Use BP Ultimate

This kind of thing definitely happens in WA, where one refinery can supply to several different brand outlets. But I don't know whether it happens with all types or just the regular stuff.

There's a guy in a car club I belong to who used to work for BP, so I'll ask him how it all works next time I see him.

Quality can certainly vary. The same guy nows works as an engineer on a ship and was telling us of an incident where he had to return many TONNES of fuel that had the wrong composition...... OOPS! That could be a lot of trips with a jerrycan... :D :eek:

I am sure Optimax is optimax... at least they are made near Geelong... I suspect Ultimate is from there myself :p

Sorry i'm not so sure about this.

But i have heard some people said that the Optimax is not a pure 98 Ron Fuel. They somewhat cheated by using an Additive to add up to 98 Ron. Is this True?

Holden said the Mobil Synergy 8000 is bad for the engine because there is lot's of Mixture in the Fuel Content that made up to 98 Ron.

So the only left and the safest fuel i have heard is BP Ultimate 98RON. Yet UK get the BP Ultimate at 95 RON only and their optimax is 98 RON.

I am a little concerned about that statment, regarding "Pure 98RON"

All the fuels are a mixture of different chemicals anyway. Some hydrocarbons/petrochemicals and other "additives". The RON is a number that is a measurement of the "anti-knock" rating as compared to iso-octane. That rating can be achieved by a variety of methods.

Whilst I don't have any documented proof, I believe the "big 3" 98's (Shell Optimax, BP Ultimate and Mobil Synergy) are each the real deal. BP have a published garantee of some sort... http://www.bp.com.au/products/fuels/....asp?menuid=ed

Yet the regular ULP in different petrol stations in one area most probably have come from one of the local refineries, hence could be anything. This is well-known common practice throught the country.

PS - Beware of Vortex - it could have water in it as I discovered much to my disgust. Sorry - that should be "be careful when buying water - it could have traces of Vortex in it." :p

Cheers,
Hymee.

UK BP should be different from here...

I think Optimax have a smiliar guarantee of quality...

IN the link of BP: reduce sulphur = cleaner air & less odour... hey stop farting! :p

sorry i might sound stupid.

Aren't the highest RON means the Cleanest Fuel?

Which mean more purer than 91 RON?

Sorry i just thought it as Logical sense.

The BP/Shell Marketing machines lead us to believe there 98 RON fuels are the "cleanest".

It is not really related to their RON (Research Octane Number), it just happens that their highest octane everyday petrols are the "cleanest". After all, they have to give us something for us to believe justifies the higher price :)

The RON is not a cleanliness measure. It is a measure of the fuels resistance to "knock". Racing fuel has a higher octane than Ultimate/Craptimax, but it is dirtier. (It still has lead in it AFIAK).

Methanol has an even higher equivalent anti-knock rating.

Basically, the higher the compression ratio of the engine, the higher octane fuel it requires. The RON does NOT INDICATE THE POWER VALUE of the fuel.

Higher octane fuels are required in higher compression engines. Higher compression engines have a higher efficiency, hence make more power.

The additives they put into the fuel to achive the higher octane numbers will affect if it makes more power or not.

I'm sure the cheaper additives will increase the RON, but not increase the energy content of the fuel, while others, such as toluene and xylene will.

Cheers,
Hymee.

Hey Hymee... When you say Vortex has water, or higher levels of it, that would be possibly caused by the fact that they do guarantee that their fuel contains no ethanol. However, a little ethanol is actually ok as it wil literally "evaporate" any water in the fuel mix or condensation left in your fuel tank.

PS- As I'm on a fuel card through Caltex, I've used Vortex of nearly 4 years without issue- I'd prefer a BP card though!

so does the additive they add is almost similar as the Octane Booster you put into your fuel?
Does that Increase the Octane level?

Also does using the 98RON will prevent a Carbon Build up on the Injector?

Does that mean using or 91RON & 95RON fuel will be nothing different than 98RON?

Skyline,

I was unlucky enough to get a bad batch of Vortex. I doubt (and didn't imply) all Vortex has water in it. Since my issue with it, and the subsequent procedings, I won't use it on principle. And since they refused to show any goodwill, how can I sit here and give them a good rap.

I had used Vortex lots before my "incident".

My fuel/fleet card has a Shell logo on the back, but I rarely go there.

Cheers,
Hymee.

Sorry if I sounded like I was sticking up for Caltex- Was just adding my experiences and 2 cents worth- And I would have the same opinion if it had happened to me. The point I was making is how a little ethanol in fuel is good and Vortex contains none :)

Skyline,

No problems there. I wasn't flaming you. Since my bad experience I tend to vent. They didn't offer me any reason to stick to the brand, so I don't pass any one :)

Everyones valuable input is encouraged.

Cheers,
Hymee.

thanks guys ....appreciate your points of view.

Interestingly, whether it is a psychologicial thing or not, the car does seem to run smoother when I've used BP Ultimate.

Could be a perception that because it is the most expensive petrol ( I normaly pay $1.07/ltr ), one thinks that it must also be the best !

Could be like when you go shopping at Target and see something you like, but think it must be crap, because it's too cheap. If you saw the same thing in a specialty store with an Italian label at 3 times the price, you would probably buy it, with a perception that it must be good quality. Btm line is that both garments could have been manufactured with the same material, out of the same plant in China. You'd never know !

I tend to agree with Chris's POV .... ie. if I'm getting worried too much about an extra $2/tank (ie. price of one coffee) then I'm getting a bit scummy in my old age !

Having said that, I have a work buddy who knows the head of Marketing at BP Aust. , so I'll try get the official party line on the differences in feul qualities between brands. With an understanding that the message will be a biased point of view.

My experience with Vortex has been actually good.. After testing all fuels for a month this is the one im going to go with for whenever i fill up my tank.

As Thommo said could be psychologicial but i have found the following:

BP Ultimate/Optimax -

I feel like they are exactly the same fuel as they both show the same sort of affect on my car.

#The car feels very jumpy at low rpms, when taking off etc.
#The car drinks it quicker also
#The car does not feel like it moves as fast as it should when you drop down a gear and try to take off.

Vortex on the other hand has shown to give the car some more spirit and actually responds better to the throttle. NO more low speed/rpm hopping etc and this in more colder weather. Also it lasts longer while driving it spirited and inner city traffic jams.

Mobil i have added to my tank before but have not tested it over a months time.

I use to get about 299 km from a tank and now its about 350 with the second last flash i believe.

Of course all this is my opinion only :)

Regards
Phillip