Best fuel for Aurion?

[Stealth]

With all this talk about the differences between 95 RON and and 98 RON, I personally doubt that it will make any difference in our Aurion without a supercharger. The whole octane thing is to give an identifier of how much the fuel can be compressed before it spontaneously ignites. The lower the octane, the less fuel that can be compressed. For a car with forced induction, the higher octane fuels are really needed here because an increase in air intake equals an increase in fuel intake.

With the Aurion, the difference in power between unleaded and premium unleaded could be understandable since the fuel injection system may pick up on the fact that there is premium in the tank (through the use of knock sensors and whatnot) and be able to increase fuel delivery. I extremely doubt that the fuel injection system would inject any more fuel however when running 98 RON than running 95 RON as you would need an increase in air intake to match. As well, I believe that all this talk about 98 cleaning your engine better than 95 is all a load of marketing hype.

Either way, I'm going to continue with using 95 RON. If you want to use 98 RON for piece of mind, then that would be your choice. I just don't like hearing it when people say that they are getting more power or better fuel economy when using 98 over 95 without giving substantial evidence to back it up. Sorry if this sounded like the start to some argument. It's been a long day and I can't word it any different right now.

Na man, that's cool. I think everyone is entitled to their opinion for sure. I just don't like when people imply that it's a total waste of money "without giving substantial evidence to back it up" for the other side of the argument. (You're not one of them, you give good advice)

It's each to their own. I think the point of the forums is to bounce ideas of people, not have people impose their will and belittle other people because of their personal choices.

[tekkyy]

As well, I believe that all this talk about 98 cleaning your engine better than 95 is all a load of marketing hype.

no it definitely makes a difference, due to the additives

just not sure how much a diference

and more importantly which direction <_<

now, every car is different

unless Toyota recommends a particular 98 fuel for the Aurion

I wouldn't start to think it might do my engine good

its like your stomach

there are hundreds of different bacterium and scientist have no clue how it all works together

if you think a simple drink like Yakut will help restore balance/health you've got to be kidding yourself

[boxerboy]

With all this talk about the differences between 95 RON and and 98 RON, I personally doubt that it will make any difference in our Aurion without a supercharger. The whole octane thing is to give an identifier of how much the fuel can be compressed before it spontaneously ignites. The lower the octane, the less fuel that can be compressed. For a car with forced induction, the higher octane fuels are really needed here because an increase in air intake equals an increase in fuel intake.

With the Aurion, the difference in power between unleaded and premium unleaded could be understandable since the fuel injection system may pick up on the fact that there is premium in the tank (through the use of knock sensors and whatnot) and be able to increase fuel delivery. I extremely doubt that the fuel injection system would inject any more fuel however when running 98 RON than running 95 RON as you would need an increase in air intake to match. As well, I believe that all this talk about 98 cleaning your engine better than 95 is all a load of marketing hype.

Either way, I'm going to continue with using 95 RON. If you want to use 98 RON for piece of mind, then that would be your choice. I just don't like hearing it when people say that they are getting more power or better fuel economy when using 98 over 95 without giving substantial evidence to back it up. Sorry if this sounded like the start to some argument. It's been a long day and I can't word it any different right now.

Na man, that's cool. I think everyone is entitled to their opinion for sure. I just don't like when people imply that it's a total waste of money "without giving substantial evidence to back it up" for the other side of the argument. (You're not one of them, you give good advice)

It's each to their own. I think the point of the forums is to bounce ideas of people, not have people impose their will and belittle other people because of their personal choices.

When the manufacturer recommends the 91ron, then the burden of proof to go to something else might belong to those supporting the diversion from the recommendation, don'tcha think?

[DJKOR]

Whoa. That was some mental overload for my simple mind. I think my brain just fried. Anyways, with this fuel discussion (argument is more fitting but carries a negative meaning) I think the best way to answer it is that there is no one best answer. I think that everyone is going to find different results with different fuels. A lot of it may account to the placebo effect, or it may not. I can't answer for this as a definite as there is no conclusive answer. To find out for real which fuel would be the most optimum, the testing procedure would be impossible to perform accurately. Everyone has different driving styles, and it may even turn out that one fuel may be suitable for a particular style, but not for another.

The best way to answer this question I guess is to try the different fuels out for yourself, and whatever you find 'feels' the best; stick with it. As I've mentioned, I personally go for 95 RON. This is not because I feel that I get better economy or more power, but because to me it feels healthier for my car. There is no evidence to back up my opinion, I just feel more comfortable using 95, and my wallet feels happier by not spending extra on 98.

[Black Presara]

Thanks for your answers guys :)

I will try different fuels and record all the distance that I travelled for a full tank and post the result later here :)

[boxerboy]

Whoa. That was some mental overload for my simple mind. I think my brain just fried. Anyways, with this fuel discussion (argument is more fitting but carries a negative meaning)

The thing is though that there must be a 'real" answer out there, that bypasses the subjectivity and emotion of the question.

I tend to plonk my belief in the resources of the manufacturer. They may stuff up occasionally, but engines and petrol are at the guts of their business and Toyota does has an excellent reputation.

If the engine doesn't ping under load then whatever the petrol used is ok. I guess the question we'd all like to know is what is objectively seen as the best performing when cost, mileage and performance are the variables measured.

Oh, and I see this written discussion, not as an argument, but a sharing of ideas and opinions. I do feel in a minority here, as performance and appearance are less important to me than reliability and cost. I have kids and school fees to consider <_< Don't get me wrong, performance and appearance are not unimportant, but the others are further up my list.

Edited November 2, 2008 by boxerboy

[Stealth]

With all this talk about the differences between 95 RON and and 98 RON, I personally doubt that it will make any difference in our Aurion without a supercharger. The whole octane thing is to give an identifier of how much the fuel can be compressed before it spontaneously ignites. The lower the octane, the less fuel that can be compressed. For a car with forced induction, the higher octane fuels are really needed here because an increase in air intake equals an increase in fuel intake.

With the Aurion, the difference in power between unleaded and premium unleaded could be understandable since the fuel injection system may pick up on the fact that there is premium in the tank (through the use of knock sensors and whatnot) and be able to increase fuel delivery. I extremely doubt that the fuel injection system would inject any more fuel however when running 98 RON than running 95 RON as you would need an increase in air intake to match. As well, I believe that all this talk about 98 cleaning your engine better than 95 is all a load of marketing hype.

Either way, I'm going to continue with using 95 RON. If you want to use 98 RON for piece of mind, then that would be your choice. I just don't like hearing it when people say that they are getting more power or better fuel economy when using 98 over 95 without giving substantial evidence to back it up. Sorry if this sounded like the start to some argument. It's been a long day and I can't word it any different right now.

Na man, that's cool. I think everyone is entitled to their opinion for sure. I just don't like when people imply that it's a total waste of money "without giving substantial evidence to back it up" for the other side of the argument. (You're not one of them, you give good advice)

It's each to their own. I think the point of the forums is to bounce ideas of people, not have people impose their will and belittle other people because of their personal choices.

When the manufacturer recommends the 91ron, then the burden of proof to go to something else might belong to those supporting the diversion from the recommendation, don'tcha think?

Not when the basis of the peoples argument is whether or not the alternative is a worthwhile investment and it's a waste of time using anything other than the minimum required RON.

[Stealth]

Hey guys,

Just a short question, which fuel is the best for aurion?

I filled 95 and got an average of 13.8 something

--------91 -------------------------- 14.9..............

is this normal??

what fuel you guys using?

cheers

Now in answer to your question. From Wikipedia:

Bear in mind that Toyota claims 204Kw from premium so the knock sensor seems to work the other way with premium fuels...

"Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause detonation.

It might seem odd that fuels with higher octane ratings explode less easily and can therefore be used in more powerful engines. However, an explosion is not desired in an internal combustion engine. An explosion will cause the pressure in the cylinder to rise far beyond the cylinder's design limits, before the force of the expanding gases can be absorbed by the piston traveling downward. This actually reduces power output, because much of the energy of combustion is absorbed as strain and heat in parts of the engine, rather than being converted to torque at the crankshaft.

A fuel with a higher octane rating can be run at a higher compression ratio without detonating. Compression is directly related to power (see engine tuning), so engines that require higher octane usually deliver more power. Engine power is a function of the fuel as well as the engine design and is related to octane rating of the fuel. Power is limited by the maximum amount of fuel-air mixture that can be forced into the combustion chamber. When the throttle is partially open, only a small fraction of the total available power is produced because the manifold is operating at pressures far below atmospheric. In this case, the octane requirement is far lower than when the throttle is opened fully and the manifold pressure increases to atmospheric pressure, or higher in the case of supercharged or turbocharged engines.

Many high-performance engines are designed to operate with a high maximum compression and thus demand high-octane premium petrol. A common misconception is that power output or fuel mileage can be improved by burning higher octane fuel than a particular engine was designed for. The power output of an engine depends in part on the energy density of its fuel, but similar fuels with different octane ratings have similar density. Since switching to a higher octane fuel does not add any more hydrocarbon content or oxygen, the engine cannot produce more power.

However, burning fuel with a lower octane rating than required by the engine often reduces power output and efficiency one way or another. If the engine begins to detonate (knock), that reduces power and efficiency for the reasons stated above. Many modern car engines feature a knock sensor – a small piezoelectric microphone which detects knock and then sends a signal to the engine control unit to retard the ignition timing. Retarding the ignition timing reduces the tendency to detonate, but also reduces power output and fuel efficiency.

Most fuel stations have two storage tanks (even those offering 3 or 4 octane levels), and you are given a mixture of the higher and lower octane fuel. Purchasing premium simply means more fuel from the higher octane tank. The detergents in the fuel are the same, Premium does not "burn cleaner."

The octane rating was developed by chemist Russell Marker at the Ethyl Corporation c1926. The selection of n-heptane as the zero point of the scale was due to the availability of very high purity n-heptane, not mixed with other isomers of heptane or octane, distilled from the resin of the Jeffrey Pine. Other sources of heptane produced from crude oil contain a mixture of different isomers with greatly differing ratings, which would not give a precise zero point."

Also keep in mind our average fuel quality (or RON) by western world standards...

"In most countries (including all of Europe and Australia) the "headline" octane rating, shown on the pump, is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" petrol in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON)."

So considering the above information and the claim of more power from the Aurion with premium fuel, it would seem that 91RON is the minimum the car can compensate for with the knock sensor...

Edited November 2, 2008 by Stealth

[DJKOR]

Very descriptive post there Stealth. Pretty much sums up what you need to know. The compression of the engine is fixed so as long as you are using at least the minimum octane fuel required, you should have no issues. If you run premium, the engine may intake a little more fuel, but it wouldn't be much (hence why it's only a 4kW increase) and this usually only occurs at high RPM. As you know the Aurion produces maximum power at about 6200RPM which at this point it would be taking in close to its maximum amount of fuel. So when cruising around normally, the difference between normal unleaded and premium shouldn't make much of a difference.

On the whole 95 or 98 issue though, the way I see it as well is that if the TRD needs 98 minimum and that has forced induction to produce an extra 41kW of power, I'm pretty sure that the N/A Aurion will not take in anywhere near enough fuel to justify going above 95 RON. Don't quote me, but I think I remember hearing as well that there were some tests done and it was found that fuels regardless of their octane rating all contained similar amounts of cleaning detergents making it less beneficial to go for a higher octane fuel.

It's all a peace of mind thing I guess. Kinda how people purchase bottled spring water with the assumption that it is clean and pure, even if it may just be highly filtered.

[Ascendant Rice]

intersting read. iguess this applies to all cars. i remember asking the service guy at the dealer about what petrol and he recommended the 98 but said 91 is fine.

[mpresara]

91 exclusively. It was one of the reasons the car was purchased.

I got less than 9L per 100k on my last decent 600+K drive. The first warning light came on at ....(around 600ks ...I can't remember) but it would've had almost 100ks left in it from memory. Well impressed.

If Toyota say 91 then that's good enough for me. 98 is throwing money away. The best fuel is the one that generates the best horsepower isn't it? If that was 95, then 98 is still a waste of money.

"Maybe just my imagination?" Could be mpresara, and most likely imho. Generally too much subjectivity in this sort of topic to be useful. Is there any objective correctly measured evidence out there?

at 7.8 its obviously better than 9 on 95 so it does make a difference using 98 with a saver docket its better i got800 from one tank and it still only took 65 litres to fill

The result may vary depending on driving condition such as city or high speed driving and driving habit.

9L/100k sounds like driving mostly at 80Km/H or faster. 91 also can do less than 10L/100KM when you do 100% highway driving.

Also, your driving habit affects the fuel consumption. Accelating hard gives you bad fuel comsumption, of course, but if you are being like a gradma(no offence ), it even gives you 9L/100KM city(50%)+highway(50%) driving.

IMO, the higher octane fuel could give you smoother and longer running distance like I stated in other reply, but more importantly, driving habit and condition affect more on fuel consumption.

I might try 95 ron the next time I do the same trip. Hwy driving was most of the 600+ks, which compared to the Commodore Acclaim I had previously was fantastic. Same size tank but 150 ks better off. I'm no slouch when driving, but i don't need to go fast to get off either. I have motorcycles for that! Smooth technique without the traffic light bravado is a very efficient fuel saving technique. A teenager that gets motion sickness keeps things steady!

I'd still prefer to read validated research before believing anything about using 98ron. Forums are sometimes wonderful places for excellent tips, but they can also be full of unsubstantiated subjective opinion...especially when it comes to emotional objects like cars.

In the long run, it doesn't matter what you use, or how you drive when you're using it..it's your money and you can do what you think best for your circumstances. Evidence however will inform much better than opinion, or anyones seatofthepantsdyno.

Most 98 Octane fuels are actually higher density. so one litre of 98 actually weighs more than 1 litre of 91, therefore more energy per litre. to some extent this is part of the reason why 98 tends to go further.

"Vortex 98 is also a high density fuel. This means it provides more energy per litre of fuel when compared to conventional unleaded. Combined with the benefits of cleaning a dirty fuel system means more kilometres from a litre of Vortex 98"

Another part of the equation along with compression, is the ignition timing. A few years ago timing was mechanically set, via the distributor position, and if you used a lower grade fuel you would get pinging under load. So the higher the Octane the more advanced timing you could use and also have a slight gain in power.

On modern cars, such as Aurion, timing is controlled via the ECU, which can vary the timing at any given moment to the driving conditions and demands on the engine. When you use 91 Octane, the ECU compensates for it. When you use 98 Octane the ECU compensates with a more advanced timing. That's why using 98 RON will give the Aurion around 204kW. More commonly we refer to all this as "knock sensor", which is actually timing compensation for the fuel and conditions we are operating under.

[DJKOR]

That's why using 98 RON will give the Aurion around 204kW.

Well this is where the discussion can divide. Are we looking at the best fuel for economy, power, or engine life? As well, when Toyota states that the power increases to 204kW with premium, do they mean 95 or 98 RON? Premium in my sense would be 95, and 98 would be like the premium of premium.

On the power discussion, we need to get a dyno day sorted out. Have one Aurion on 91 RON, another on 95 RON, and another on 98 RON. That way we will be able to find out which fuel would be best for power. I'm sure a QLD dyno day shouldn't be too far off and we have enough Aurion's here to perform that test.

[CHA54]

you'd have to run each car on it's designated fuel for at least a tank's worth to let the ECU learn it's trims to suit the new fuel... Then all three would need to be using the same oil, tyre size, exhaust, wheels etc etc to try and take out as many variables as possible.

I prefer to look after my engines, so only run 98. Doing so allows the ECU to run more ignition advance (compare the ignition advance with an obd2 scan tool when running 91 and 98...) which increases the torque, power and economy.

[AUR30N]

With all this talk about the differences between 95 RON and and 98 RON, I personally doubt that it will make any difference in our Aurion without a supercharger. The whole octane thing is to give an identifier of how much the fuel can be compressed before it spontaneously ignites. The lower the octane, the less fuel that can be compressed. For a car with forced induction, the higher octane fuels are really needed here because an increase in air intake equals an increase in fuel intake.

With the Aurion, the difference in power between unleaded and premium unleaded could be understandable since the fuel injection system may pick up on the fact that there is premium in the tank (through the use of knock sensors and whatnot) and be able to increase fuel delivery. I extremely doubt that the fuel injection system would inject any more fuel however when running 98 RON than running 95 RON as you would need an increase in air intake to match. As well, I believe that all this talk about 98 cleaning your engine better than 95 is all a load of marketing hype.

Either way, I'm going to continue with using 95 RON. If you want to use 98 RON for piece of mind, then that would be your choice. I just don't like hearing it when people say that they are getting more power or better fuel economy when using 98 over 95 without giving substantial evidence to back it up. Sorry if this sounded like the start to some argument. It's been a long day and I can't word it any different right now.

Higher Rons are for engines with highrer compression to stop it from knocking.......allot of people are under the assumption that it makes there car go better or get more km's with hiogher ron not the case if the engine does not state it needs it then your just pumping wasted money into your car

Azza

[DJKOR]

Higher Rons are for engines with highrer compression to stop it from knocking.......allot of people are under the assumption that it makes there car go better or get more km's with hiogher ron not the case if the engine does not state it needs it then your just pumping wasted money into your car

Exactly. This was the point I was trying to make in post 34 above.

[AUR30N]

And for those people that have turbos and are asking well my car has low compression yes that correct turbos do have low compression ratio but reason why higher ron is needed is because when you come on boost your comp ratio jumps higher hope it all makes sense now.

Azza

[riftime]

I have a Presara. I've kept records since new of every fuel type used, distance travelled, etc. It's been 20,000 kms, I hope to get some time soon to analyse all that. I'll post my findings here once I get around to it. However, even without analysis, I have noticed that I travel further with 98 fuel. Whether the additional distance warrants the additional price I don't know without the detailed analysis.

On a slight tangent, I was surprised by the fuel economy last week.

Filled up with 95. Driving from Werribee to Melb Airport (Tullamarine) 98% freeway driving the fuel consumption went down to 7.3 L/100kms !!! It was going down by about .1 every few kms, maybe I could have squeezed another few minor increments if I had further to travel on the freeway.

- Full tank of fuel

- 2 adults 1 child

- Friggin hot day, A/C working

- Light traffic

- 20,000 kms on the odometer

- Last serviced at 15,000

Note that the fuel consumption was calculated by the car (as per dash display). Not sure of it's accuracy, but it's been pretty good compared to my paper logs.

[PsychoRez]

In my country our regular is 95 and our premium is 98, But i still use the premium for the piece of mind, And the extra few HP's make you feel better at least Lol. And its no wonder i get 13L/100Km's +, Guess 98 Burns faster than 95/91.

Nowa days I'm averaging out at 13L/100Km, Minimum i got for a while is 12L/100KM. I just very rarely get an average below those. Before even 13's were impossible to get for me, Guess i changed my driving habits a bit, Been driving slower now days.

One day i was driving during the day, The weather was fantastic, Some cloud in the sky, I looked at my gauges and i couldn't believe my eyes!, 9.8L/100Km!!!. And it even went lower to 95 and 94, I was ecstatic, I started taking pictures with my mobile phone.

[boxerboy]

PsychcoRez...I'm guessing you pay pittance for petrol in Bahrain? How much per litre for 95 and 98??

[Freddo]

I thought the higher the octane the less fuel goes in. Hence better fuel economy - better kilometerage.

[prometheus]

The higher the Octane , the more energy the fuel contains , so for the same amount you get more power , therefore often using less to get the same milaeage as a lower octane fuel.

[David the Viking]

The higher the Octane , the more energy the fuel contains , so for the same amount you get more power , therefore often using less to get the same milaeage as a lower octane fuel.

The higher the octane rating the less volatile the fuel is. So it needs a higher temperature to ignite. Fuel density is how much energy a fuel has, a higher density = more energy.

Thats the problem with ethanol as it has a higher octane rating then PULP but is less dense so it has less energy and more is needed to be burnt to go the same distance. LPG is also in the same boat.

[PsychoRez]

PsychcoRez...I'm guessing you pay pittance for petrol in Bahrain? How much per litre for 95 and 98??

When converted to aussieland dollars, 98 = 0.418819AUD per litre.

Actually I've been told our premium is 98 but i never really checked up on it. Might ask the next time i head in for a refill. But it makes sense since i get such high fuel average all the damn time.

Yesterday i was driving in short bursts and a bit fast i guess, And my fuel average was 19!, But maybe its because i didn't drive for a long period of time and i had just poured fuel that morning "Takes time till it averages out?. Now its at 14.