Premium fuel worth the extra cost? What exactly are the benefits of using it?

L[Deactivated] on 13/10/2013 - 00:44

Ok, I'll start this by confessing I know NOTHING about cars.

When I used to drive my beloved 20 year old Volvo (240) we were advised by our mechanic to use the premium (most expensive one - Vortex etc) fuel to help it run more smoothly. And it did help - I could tell the difference when we tried the regular fuel. When we were discussing the extra cost one day the mechanic also mentioned about the tank lasting slightly longer with premium than regular - which would help offset the cost.

Now we have a nice newer, shinier V50 (yep, still a Volvo) and I'm wondering if using premium fuel is really giving us sufficient benefits that justify the extra cost. It's no longer an old car (it is a 2008) and it isn't exactly a race car either.

So can I please dip into the collective pool of wisdom and hear people's thoughts on the benefits/necessity of premium fuel.

Thank you.

Automotive

Comments

  • WaffleCrusader on 13/10/2013 - 02:12
    +3

    My very limited knowledge on the matter: it's not your decision to choose what fuel you give your car. If it requires premium, you give it premium as that's what the engine was designed for. If it only requires regular unleaded then you can rejoice as you have the option of buying premium albeit the benefits won't really be noticeable.

    After a quick google I also found this (in reference to cars made for premium petrol).

    "Using unleaded petrol with lesser octane (regular petrol) could produce engine knocking resulting in expensive damage, especially when driven aggressively or heavily loaded."

    • plmko on 13/10/2013 - 02:16

      Yeah I think there was a thread here in OzB some years back about used cars and some mechanic guy was ranting on about how one client totally neglected properly maintaining his Merc and the engine was clogged up to the point of needing $12k worth of repairs.

    • cannedhams on 27/10/2013 - 16:24

      If you use 91 fuel in a European car you run the risk of frying the engine. The 91 stuff fires too early, leading to the engine potentially overheating. You really should use 95 juice or above in your Volvo.

  • nephilim on 13/10/2013 - 02:25
    -2

    If you look at wikipedia, find that USA/Japan have 90 as standard, Aus 91 and Europe between 93-95. Think is easy way to see where your car is made and what fuel it would be optimised for.

    • _Bruce_ on 13/10/2013 - 08:33
      +8

      The US uses a different rating system (not RON) so don't confuse the numbers.

  • snappy1234 on 13/10/2013 - 06:45
    +1

    http://au.news.yahoo.com/today-tonight/consumer/cars/article…

    Interesting test…

    ( i have a two year old car (Subaru) and and a twelve year old car (Ford) and the Ford ran much sweeter on the 98(less hesitation on first accelerating mostly)

    Would like to try over a long period to be sure.

    • pdperth on 13/10/2013 - 08:34
      +2

      It costs about 10 pcnt more and i get better than 10 pcnt mileage for my aurion. Check out your own mileage on a full tank - mine runs better and is more responsive - same for my last car - the avalon.

    • _Bruce_ on 13/10/2013 - 08:34
      +18

      Almost the least trustworthy source in the world.

      • snappy1234 on 13/10/2013 - 09:34
        +1

        Hey Bruce…did you watch it ?…i agree i normally would never link TT or ACA
        but it seemed a much better story than the usual dross :)

    • MementoMori on 14/10/2013 - 11:56
      +5

      Guys - no way. In general, TT/ACA stories are funded by ADVERTISERS. In this case, fuel companies.

      That story was obviously pro 98 RON and anti e10.

      • edgar28 on 14/10/2013 - 15:36

        the TT claim e10 was the champion last time, tested on 60km/hr

  • _Bruce_ on 13/10/2013 - 08:33
    +5

    Bascially there are two answers:

    If you car has a knock sensor (your V50 does):
    The engine is designed to run at the octane specified in the manual (I am guessing 95 in this case). If you put in a higher rated fuel it will do almost nothing (ie: 98). If you put in lower rated fuel the knock sensor will detect this and alter the fuel mix and other settings. This is perfectly safe but expect the car not to run quite as well. Every car will be different so hard to say if 91/95 will be more cost effective in this case but there will definitely be a benefit to running 95.

    If your car does not have a kick sensor:

    Do not put in lower rated that the manual tells you. The engine will 'knock' and 'ping' running poorly at best and causing damage at worst. Putting in high rated is still pointless.

    Edit: Because many people are arguing against this let me quote wikipedia (sure, not definitive, but better than 'I said so'):
    "A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power."

    • zerocritical on 13/10/2013 - 09:27
      -4

      It's true that higher octane fuel does not burn better to produce more energy. The difference comes on a longer run. Higher octane fuel keeps the engine relatively cleaner than lower octane fuels and hence cleaner the engine, better will be it's efficiency.

      • _Bruce_ on 13/10/2013 - 19:31
        +5

        This is pretty much entirely marketing. They argue this because it is the only thing that can argue as it is harder to prove wrong that the direct efficiency argument.

    • Seraphaem on 13/10/2013 - 11:53
      -4

      Higher octane rating creates a more powerful explosion in the engine therefore providing more power. An example of this is in V8 supercars in which they currently use an E85 ethanol blend, which they swapped to from 98 RON. Ethanol has a far lower energy density than petrol, however the higher theoretical octane rating allows them to gain more power. The same can be seen with diesel engines as well. They have a higher energy density than petrol allowing them to be more fuel efficient, but petrol engines will always be more powerful.

      Another advantage of using 95 or 98 over 91 (besides the higher octane rating) is that they also include cleaning agents in the fuel. Just something to keep in mind.

      • macrocephalic on 14/10/2013 - 15:17
        +5

        Higher octane rated fuel prevents against pre-detonation (aka knocking). Some cars can adjust the fuelling and timing to take advantage of this, but if your car doesn't do this, and it's not designed to run on higher octane fuel then you won't get anything.

        In V8 racing they will run higher compression - so they need the higher octane to prevent knocking, and they run the engine hard with a chance of overheating - so the extra cooling benefit of alcohol based fuels helps.

        • zeomega on 17/10/2013 - 00:40

          Most if not all modern cars can adjust fuel and timing. Old cars without any form of variable valve timing will not be able to compensate for good/bad fuel. So put in the bare minimum if you dont have vvt and you'll be fine.

  • cloudy on 13/10/2013 - 11:46
    +12

    I got a feeling these could be one of those endless debates/threads.

  • kaos on 13/10/2013 - 13:12
    -3

    First, look in the manual for your car to see if lower octane fuel cannot be used. If you're ok, let's continue assuming you can use 91, 95 or 98 octane, which seem to be the most available in Australia.

    here's an assumption that I feel is true but I can't give you a source right now- it came from a racing car engineer. 'The calorific content/ or stored energy of an ethanol blend fuel has approximately 10% less energy per litre'

    Let's make a further assumption that 98 octane will give you nearly 10% more energy and see how that works out.

    If your car can take 91, see how far a tank will take you. Then compare with 95. In my 2001 Nissan Pulsar, a tank of 91 will take me about 450-500km, and a tank of 95 will go for 500-600km. This is very dependant on the type of driving (city, highway etc) but you can see there is a 10% difference as expected.

    I'm pretty sure there is no point putting 98 in my shitbox so I have no results for this.

    In summary- I only ever buy 91 when it is more than 10% cheaper than 91. Which is almost never. If 91 is 1.57 per litre and 95 is 1.63, buy the 95- it will take you 10% further for only 3-4% more cost.

    I did used to own a TVR Griffith, the user manual said to only use premium unleaded so that's what it got fed. I also had a Lotus Elise (went faster, with less hesitation) which like premium a lot better than 95 but I guess both of those examples are what you'd expect……..

    • cvas on 16/10/2013 - 17:20

      So at best, you get an extra 100km per tank by going from 91 to 95? why don't you try 98 then it might take you an extra 200km?

  • striker5950 on 13/10/2013 - 17:24

    I drive a 350z, its recommended to fill it up with 98 ultimate all the time, however I used to fill it up with e10 and started to notice a decrease in acceleration, so went back to 98, keep in mind this is a sport car and it might be different for your car, but I've also read that if its factory recommended to use premium fuel than you should because it could possibly ruin your engine, it has something to do with the compression ratio of the engine and how it burns the fuel.

    • twodollah on 14/10/2013 - 09:57
      -5

      e10 has a higher octane rating than 98 ultimate. You will see some fuels of 100+ octane rating. This is achieved through the addition of ethanol.

      • macrocephalic on 14/10/2013 - 15:20
        +2

        It's true that ethanol has a higher RON rating than petrol, but E10 that is sold at fuel stations is actually about 88RON with 10% ethanol - which brings it up to 91 (unless otherwise stated by them). The RON rating that it's sold at is the end product, not the rating of the petrol component.

  • Dr Techno on 13/10/2013 - 21:05

    I use solely BP Ultimate. They provide a guarantee on the fuel, so they pay for any repairs if you get any dodgy fuel plus they contain 0 ethanol. I drive a 300zx which I do all the repairs myself on, its fuel system is not rated for ethanol. Harms rubber & plastic components of older fuel systems. Cheaper fuel is commonly blended with ethanol. Since I do my own maintenance I prefer using a higher quality product. Even use it in my lawn mower, higher octane gives it a good kick.

    I've heard from a petrol tank driver that, the left over fuel at the bottom of petrol tank trucks returning to depo are reprocessed for non-premium fuel. Hmmm.

    • MATTDAMON on 14/10/2013 - 17:33

      Only if you can prove the fuel was the cause, and good luck getting money out of BP, if the company im working for cant even get our pay out of them (around the tune of 30 million) good luck getting a few thousand out of them.

      Oh and PS all 3 of the 98's (Vortex, Ultimate and V-Power) all carry the same guarantee

  • francis.tks on 13/10/2013 - 22:55
    +1

    I was thinking of saying that e10 is more environmental friendly, but that is a whole different thing all together.

  • bluechan on 13/10/2013 - 23:15
    +2

    I keep fuel stats on cars I drive/drove.

    So for my 1999 Nissan Pulsar: Premium unleaded fuels did provide a performance increase. But it wasn't proportional to the extra cost from normal unleaded.

    RACV did a study and found similar results:

    http://www.drive.com.au/Editorial/ArticleDetail.aspx?Article…

    Your results may vary.

    PS. Fuelly is a great site to help keep track of your fuel usage: http://www.fuelly.com

    • zooter on 14/10/2013 - 12:25

      Fuelly is great find!

    • skegger on 16/10/2013 - 18:21

      I came here to post this. My '98 Pulsar got a little bit more milage, but after logging results like a nerd for about 6 months the cost per kilometer wasn't worth the extra distance.

  • keverns on 14/10/2013 - 00:25
    +1

    if your car manual says to use 'this' petrol, use it.
    there's no major benefits to performance increase or mileage for the cost of petrol itself. maybe help the environment side of things or a slightly cleaner engine.

    if you're jumping onto ethanol, when your car is not tuned for, you'd be just destroying your engine in the long term. parts of the engines, ie o rings, seals etc will be eaten up by ethanol because they cant sustain the type of chemical structure of ethanol.

    for the cleaning side of things, if you follow your service book, just clean the injectors then. though i see this as a marketing tactic for people that don't know much about cars. sure it might clean better when you look at A vs. B vs. C petrol, but when you're combine it with cars its a different result.

    if you want to use better fuel properly, the car needs a tune to suit the destined octane rating. and in some cases, upgrade fuel lines for e85. otherwise just wasting money.

    regarding v8 super cars or any other race car or even the new cars, the cars a tuned to the petrol specification, its not a simple lets use this petrol for today and expect good things out of it.

    so key points is…. the car must be tuned to the petrol. which i doubt mainly daily drivers would do.

  • [Deactivated] on 14/10/2013 - 01:19

    Daily drive 1. 05 astra ts.

    E10. Will not use.
    95. Recommended in car manual and get approx 450 to 500km per tank.
    98. Get 550 average per tank.

    Daily drive 2. 12 jeep Cherokee.

    Always put 98.

    Hobby car. 87 vl commodore.

    100 ( shell ultimate) was a blend of 98 and ethenol it destroyed all my rubber lines in the fuel system due to the ethenol content and cost a fair bit to fix.
    Tuned to use 98.
    More power.
    Cleaner burning fuel and pulled head off to do some work and the tops of cylinders are near spotless and head as well.

    • Shwayne on 15/10/2013 - 10:09

      You might as well put sand in your petrol tank if you're putting ethanol in it. :D

      • [Deactivated] on 15/10/2013 - 16:42

        Learnt the hard way but lucky to find out what was going on at the mechanics on rego check.

  • [Deactivated] on 14/10/2013 - 01:21

    Forgot to add all 3 cars benifited from 98 and it shows in response. My tuned car get most benifit but still even the astra shows resaults by the amount of ks per tank.

  • Jalif on 14/10/2013 - 08:26
    +1

    If your car is less than 15 years old, and fitted with a knock sensor, it may advance the ignition timing to get more power or more milage.

    Not all cars do.

    You get power or milage, depending on how you drive.

    Higher octane fuels also have a higher percentage of detergent to clean build up from the engine.

    On the downside higher octane fuels are harder to ignite so of there is a weakness in the cars ignition system, this can result in lower than expected performance.

    The added detergent can cause issues with older cars where the build up is functioning as a seal. Again rarely.

    Stay clear of e10. The ethanol bonds with water and can accumulate it from the air, and forms a homogeneous mix through the fuel.

    If stored correctly it is fine, but how much do you trust your local servo?

    • MATTDAMON on 14/10/2013 - 17:38
      +1

      You have more chance of getting a load full of scale, rot and ground water from old tanks then having the E10 absorb enough water to cause issue. Hell even in the fuel tank of your own car there would be condensation formed on a regular basis.

      Most busy servo's turn over that much fuel it rarely sits for more then a few days, and now with VRS mandatory in the next 18 months all servo's are either replacing/repairing inground tanks and replacing bowsers so they are VRS compatible.

  • twodollah on 14/10/2013 - 10:02
    +18

    Chemical engineer experienced in petroleum engineering here - fill your car with what's on the manual, not lower. There are no benefits on using a fuel with a higher octane rating than what is specified for your car as its engine's compression ratio will not utilize it.

    There are a lot of people with anecdotal evidence suggesting that using higher RON fuels increase mileage. There is no scientific evidence to provide a reason for this AFAIK. IMO, I would attribute it to a placebo effect.

    • _Bruce_ on 14/10/2013 - 17:54
      +2

      There is no scientific evidence to provide a reason for this AFAIK. IMO, I would attribute it to a placebo effect.

      It is a remarkably hard to break myth for some reason.

      • PresidentClinton on 15/10/2013 - 18:02

        People will believe their mate Bazza over actual science. I gave up trying to convince my own father that higher octane petrol is just a waste of money for his 2008 astra.

      • jimborino on 15/10/2013 - 21:39

        The people who buy higher octane fuel than required are not the ones to care about scientific proof…and the ones who do care about scientific proof do not buy higher octane fuel than required.

    • Kermitall on 15/10/2013 - 18:22

      If my car has an EFI system with a knock sensor so it can adjust the timing (normally to prevent knocking at high load & low revs), what is stopping that system from being used to change the timing to allow a longer compression stroke/later spark ignition if the fuel can be compressed more before it self ignites (ie higher RON)?

      As I understand it this is what allows better economy/power with modern cars using higher RON fuels.

      • _Bruce_ on 15/10/2013 - 19:26
        +3

        There is a difference between reacting to the knock and adjusting to stop damage and being tuned for that octane level.

  • Cluster on 14/10/2013 - 14:52
    +3

    Use the minimum specified octane rating in your car's instruction manual and nothing more. Ignore the marketing department spiels about 'special cleaners' and such in 95/98 octane fuel. Petrol is itself a powerful solvent.

    Cars with high engine compression ratios traditionally required premium fuel. These were performance cars so people thought it was the fuel that made them go faster. People associated the fuel itself as imbibing the cars with extra performance therefore the false belief that higher octane fuel makes all cars go faster/longer/harder stuck.

  • lead_org on 14/10/2013 - 18:30
    +1

    Modern cars have knock sensors so they can run either on Premium or Regular Octane petrol. Premium fuel in modern cars will give greater power output, and lot of them have cleaning additives added to clean up the engine to remove any waxes that may build up overtime. With the cleaning benefits i use quarter tank of E10 petrol with every 3/4 tank of normal petrol, i run it till near empty, it does a much better job in cleaning the engine. This method also prevents ethanol in the petrol from absorbing water, which may cause corrosion. Also, if you don't use the car a lot, don't use the ethanol mixed petrol, as the emulsifier will evaporate, and the petrol + ethanol will separate the layer, which will absorb the water and cause corrosion.

  • adn on 15/10/2013 - 09:51

    98 all the way. but my car is imported and has the 180km/hr speed limit too!

  • Shwayne on 15/10/2013 - 10:08

    There's two ends of the spectrum.

    There's cars that can take E10, ULP (91,92 octane #) and cars that need P(remium)ULP (95,96 - 98 octane #).

    Cars that require/operate on ULP, do not benefit from PULP. (You may get slightly better mileage, but no improvement in performance or anything like that, and it will probably end up costing you more per km.)

    Cars that can operate on E10 will operate better on ULP.

    My advice is to avoid E10, and to use the lowest octane number your car is designed to use (which is most likely 91,92 unless it is a sports car).

    E10 is a marketing stint layered over a legal limitation that allows the industry to distrubute petrol with 10% ethanol, which is not a good thing for the consumer.

    Note that if ULP is less than 10% more expensive than the E10 you are actually wasting money, as Ethanol != combustable fuel. (You get less mileage and less torque from E10.)

    TL;DR: Buy the lowest octane number your car is designed to operate on, and avoid E10.

    • twodollah on 15/10/2013 - 11:29
      +1

      Ethanol is a combustible fuel, otherwise it'll just drown your engine. The reason you get less mileage from E10 is because ethanol has a lower specific energy compared to petroleum.

      E10 is safe for almost all modern cars according to studies conducted a few years ago. IIRC, negative perceptions of ethanol fuel in Australia was caused in the 1990's when there was a lack of strict supervision of the ethanol fuel industry where ethanol fuel were sold with vastly higher composition of ethanol than actually specified. E.g. E10 containing 25% ethanol instead of 10%.

      • [Deactivated] on 16/10/2013 - 03:57

        E10 made my rubber fuel lines brittle and cost me aa bit and time to replace all parts. So e10 is no good in my books and ks per tank are shocking.

        • altomic on 17/10/2013 - 02:35

          been using E10 in my hyundai tucson for the last 6 years, no problems at all.

  • BuuBox on 15/10/2013 - 11:41
    +1

    The octane rating is merely a rating of the detonation resistance properties of the fuel. It is not a magic rating that adds power. Running 95 or 98 octane fuel on an engine that does not detonate on 91 octane fuel will yield no benefits.

    The issue with relying on the knock sensor when running 91 octane in an engine that specifies 95 or 98 (e.g. the Volvo V50) is that the ECU maps are expecting the detonation resistance of 95 octane fuel. The ECU will pull timing and add fuel if detonation is detected from the knock sensor to try and compensate, but this requires the engine to detonate in the first place. The ECU will constantly be trying to advance the timing back to where it should be.

    As the car gets older, the requirement for higher octane fuel increases rather than decreases. This may be marginal depending on the condition of the engine, but oil contamination (i.e. blow by) will effectively reduce the octane rating of the fuel. It is somewhat of a vicious cycle - if an engine is run on lower than specified fuel, detonation will impact ring seal (at a minimum) which will further increase the requirement for higher octane fuel. On higher stressed engines, the impact could be far worse (e.g. a hole in the piston). The V50 appears to be turbocharged so this is relevant.

    Note that any "hesitation" when running on 91 octane fuel is the engine detonating and the ECU attempting to compensate. This is not good.

    This is all generally a one way road - the ECU will pull timing (and richen the mixture) on detonation, rather than add timing and run leaner when detonation is not detected (there are some exceptions).

    This is a very simple explanation, but I hope it's helpful. Long story short, stick to the manufacturer specified octane rating at a minimum.

  • Kempe on 15/10/2013 - 11:46

    Just use what the handbook recommends as putting in higher octane is just a waste of money as the engine is not tuned for it.
    Any perceived advantages are the placebo effect like the car running better after you have spent all day polishing it

    • BuuBox on 15/10/2013 - 11:59
      -1

      Surprisingly some fairly mundane cars are tuned to the limits of 91 octane fuel in order to achieve power and economy targets.

      As a result, even these A to B vehicles will detonate in some scenarios, particularly given hot ambient temperatures on 91 octane fuel. In these cases, 95 octane fuel would be advantageous for maintaining performance and ensuring engine longevity. This is where E10 has some advantages given an octane rating of around 93 to 94 and a price advantage over regular 91 octane unleaded.

      Remember you can damage a car by running a fuel with an octane rating lower than required. You cannot damage a car by running a fuel with a higher octane rating than required. "Required" may mean what the manufacturer specifies, or what is experienced in real world running conditions as per my example.

  • Jikx on 15/10/2013 - 19:03

    I definitely notice using RON98 over RON95 - in a turbo car however, and I generally don't see a difference in fuel consumption since I tend to speed up faster wasting fuel.

    What I use now, which some people will hate me for, is United Petroliums E10 since it's actually Ron 95. Sure it's definitely not as efficient (probably about 5% greater fuel consumption), but saves 16 cents a litre.

    Only do this if your can actually use 10% ethanol of course!

  • [Deactivated] on 15/10/2013 - 23:42
    -1

    I just ALWAYS use 91 octane, I'll use 98 if the fuel tank is completely empty/it's payday/only 20L to give the engine a quick clean.

  • philart on 16/10/2013 - 01:40

    My personal fuel consumption testing with E10 and ULP 91 in our 2012 Corolla hatch suggests we get ~5% less mileage with E10. The missus and me are petrol misers so perhaps with a lead foot the difference might be greater. We've never tried premium so wouldn't know if it's cost effective. Toyota doesn't recommend premium and modern engines burn cleanly, I believe that as I've never heard of a modern car needing routine de-cokes as was the case 30+ years ago.

  • String name on 16/10/2013 - 01:48

    AFAIK and was told, what petrol you put into the car is determined by the compression ratio chosen for that engine back in the manufacturing process. Cars that require higher octane fuels have higher compression ratios, which will ultimately create more power generated through the "combustion" phase. If you put in high octane fuels in a car that does not require it, you do not get an effective combustion of the fuel, and there will be higher unburnt fuel build up, inefficient fuel usage, and finally paying more when it isn't required.

    • BuuBox on 16/10/2013 - 11:54

      The difference in combustibility between 91 octane and 98 octane fuel is not so great as to actually cause problems when using it in a car designed for 91 octane.

      Unburnt fuel does not "build up".

  • pao2x on 16/10/2013 - 10:39

    NSW government FAQ on e10 fuel economy. Of course it might be biased towards E10 use but should still be based on research.

    http://www.biofuels.nsw.gov.au/biofuels_faq/e10_fuel_economy

  • [Deactivated] on 16/10/2013 - 11:43
    +7

    Thank you for all the feedback…it has been helpful and also helps explain why a Google did not yield a straightforward answer either! I never realised it wasn't a cut and dry topic.

    Found the manual and looked it up (yeah, it never dawned on me they'd put info like that in there - I am usually somewhat intelligent, but seem to be a total numpty when it comes to these kind of things).

    Manual says;

    • 91 RON should only be used in exceptional cases.
    • 95 RON can be used for normal driving.
    • 98 RON is recommended for optimum performance and minimum fuel consumption.

    It also says not to drink the fuel…props to Volvo for those extra special safety tips…looks like those petrol milkshakes are now off the menu.

    So am thinking I'll just stick with the Vortex (98) and stop the sharp inhale of breath each time I look at the price difference (because apparently breathing in petrol fumes is also dangerous…thank you Volvo manual once again).

    • MATTDAMON on 16/10/2013 - 14:05

      Its only ~5c difference between 95 and 98.

    • IamEzza on 16/10/2013 - 14:27

      According to your manual your engine is tuned to take advantage of higher octanes, so by using higher octanes you will get better fuel mileage which will offset the extra cost.

    • Windows7forever on 16/10/2013 - 16:30

      Capt Obvious must work for Volvo in the safety dept.

      • _Bruce_ on 16/10/2013 - 18:59
        +1

        Nope, the legal 'don't sue us' dept.

    • apu on 17/10/2013 - 16:59
      +1

      I wonder if the fuels taste different…

  • BrisLis on 16/10/2013 - 16:43
    -2

    I know absolutely nothing about cars, but I use only premium fuel since I ran the calculations and found the huge amount of extra mileage I get out of a tank covers the extra cost.

    • PresidentClinton on 17/10/2013 - 12:21
      +4

      Thank you for subsidising our regular fuel.

  • tonyjzx on 16/10/2013 - 23:59

    thing is european cars generally arent developed to work on 91 as 91 doesnt exist over there

    volvo being luxury cars should be run on 95+

    look at bmw mercedes audi etc. all say 95+

    • zeomega on 17/10/2013 - 01:30

      nvm.

  • Medrad on 21/10/2013 - 15:45
    +1

    Wow… reading through there are so many points of view.

    I'll put in my $0.02 worth.

    Higher octane rating = more complete combustion preventing early or incomplete combustion.

    As mentioned above, increase in octane rating doesn't increase power, but allows you to modify your engine's running so it can modify the fuel/air ratio and produce more power by not knocking or retarding things. This is the reason Avgas (stuff you put in planes) has such a high octane rating. You don't want your engine playing up when many thousands of feet in the air.

    If the car can run on 91RON normally and you put in 98RON fuel, it won't do much. The additives might "clean" the engine etc etc but won't produce more power. If you tune the cars' engine/computer to adapt to the better combusting fuel you'll get more power with the reliability that a higher-octane fuel gives.

  • brgnhntr on 23/10/2013 - 12:34

    I dont have the technical knowledge about the difference apart from what the oil companies advertise but from my experience I can tell u there is a difference between 91 octane(bp premium unleaded) and 98 octane (Bp Ultimate. I always fill my Honda CBR fireblade with 98 but this time there was none available at the oil station and the tank was really dry. So I had to fill up the best available which was 91. As the tank was empty, new fuel went straight into the engine for combustion and I could tell the difference straight away. The bike started to knock and started to ride rough. I only filled up just enough to get me to next station ($5). Filled up with 98 octane (Bp ultimate). It took a while for the not so good fuel to be used and now the bike has gone back to excellent. as the bikes dont take much to fill up (Around $25), I dont mind using 98 but I guess it can become an issue when u fill up the car ($90). I use 91 in my Ford XR6. I have tried 98, it is a bit better but I dont think it is worth. It did do few Kms extra on 98 octane and much smoother running.

  • brgnhntr on 23/10/2013 - 12:36

    But ethanol mixed fuels are a definite NO NO…..

  • Geewhizz on 24/10/2013 - 06:51

    We had an 87 Pulsar until a few years ago. We found it no more expensive to use Vortex, because the extra distance we got from it negated the extra cost, and it did run much more smoothly.

    We replaced it with a lease vehicle, and for the first 5 years continued to use Vortex because of this experience. When we released, high octane fuels were excluded, and to be honest, we didn't really notice much difference performance-wise. As for the mileage, I must admit I didn't take much notice.

  • [Deactivated] on 29/10/2013 - 08:01

    Had a 2010 Nissan Dualis…ran it on Premium since Day 1 and thought we were doing good in the long run….2 years later, we decided to use 91 RON..guess what? No difference…in fact, the 91 RON seemed to give the car a bit more response…weird or what??? It would seem like the 2.0L in our Dualis liked the cheap fuel more…and mileage was still the same thirsty 9.5L/100km…

    However, rule of thumb is that you should check the fuel flap…if it says "Premium Unleaded Fuel Only"…then fill it with premium! This especially holds true for turbo-charged cars…I drive a WRX and don't dare use anything lesser…I found out the hard way many years ago when I had a R33 Skyline - ran out of juice and filled it up using 91RON…the car started spluttering and knocking.

  • Donavann on 09/11/2013 - 03:30

    Well if you put in reduced, rated fuel the affect indicator will identify this and change the fuel mix and other configurations. This is completely secure, but expect the car not to run quite as well.

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