Fuels – which should you use?

petrol pump

Which premium unleaded fuel do you find the most efficient and cost effective?

Motorists can be forgiven for being confused about the fuels available and what their car needs.  There are five types of petrol now available (standard unleaded, 95 premium, 98 ultra premium, E10 and E85) as well as Diesel and LPG.

This blog is the first in our series on fuels to help clear up the confusion about which fuels are the best to use. We begin with premium unleaded.

Premium Fuels – is there a benefit?

Petrol vehicles are designed for a specific octane fuel and normally do not benefit from using higher octane fuel.

If the manual says you can use more than one type of petrol or blend, you may get the advantage of reduced fuel consumption (but only if your vehicle’s engine automatically adjusts its parameters to take advantage of higher octane).  Conversely, you may be able to save money by using a lower octane fuel, if the manufacturer states the vehicle will run normally on it.

As a rule of thumb:

  • 95 premium can give around 4% lower fuel consumption than 91, assuming the engine computer adjusts to take advantage of the octane difference.
  • 98 might give 3% reduction over 95, again assuming the computer adjusts the engine parameters.

The overriding recommendation is to consult the owner’s manual for your vehicle and use fuel of the octane listed.  Some motorists report lower fuel consumption using higher octane fuel.  If you wish to check this for yourself, be sure to record your fuel consumption for at least 10 tanks before you make the change, so you have a good baseline.  Try and check your baseline under normal conditions – if you have an unusual country trip in the middle of your test period, for instance, it will result in atypical figures.  Conversely, if your driving is normally on highways, a week of city driving will bias your figures.  Then change to the higher octane fuel and do a check for the next 10 tank fills and compare the figures.  If the savings from any reduced fuel consumption are outweighed by the extra cost of the premium fuel, it is obviously not economically sensible to use the higher octane.

In our next blog, we’ll look at ethanol in petrol (E85 and E10).

Which premium unleaded fuel do you find the most efficient and cost effective?

This entry was posted in E10, Fuels, LPG, Premium Unleaded Petrol and tagged , , , by Jack @ NRMA. Bookmark the permalink.

About Jack @ NRMA

Jack is the NRMA’s advocate and champion for vehicle technical and environmental issues. He has been with NRMA for 24 years and previous to that worked for a vehicle manufacturer and ran an emissions laboratory. He analyses new technologies, suggests any testing required and manages the NRMA’s involvement in national programs such as ANCAP, the high speed crash test program that provides safety ratings for purchasers of new vehicles; the Used Car Safety Ratings, that provide similar ratings for used cars; the Child Restraint Evaluation Program, to rate child restraints; and the Consumer Rating and Assessment of Safety Helmets (CRASH) to rate motorcycle helmets. Jack also presents NRMA policy and test results from these programs in the media, so you may see him on TV or hear him on the radio.

51 thoughts on “Fuels – which should you use?

  1. My car runs much better on 95p then it did on e10. When I was using e10 the engine used to make a gwad forsaken noise emitting from the engine.

  2. My 99 Astra runs better on 98 than the recommended 91 RON fuel. I saw some figures a while back suggesting a few extra Kw and Nm by using better fuel. The car is better to drive, and fuel economy savings are inline with your guideline (I estimate around 8% purely city driving).

  3. Hi,..I had thought about this earlier and your article clarifies it well. There is no significant benefit, using the premium fuels. I drive a 1999 model Ford and haven’t realised any significant benefit using premium quality. Thanks for clearing the air around the claim.

  4. I have decided not to use E10 regularly since one of our cars had a problem with seals in the fuel lines which several mechanics say is a result of using E10 fuel. Have heard and seen similar reports since. We cannot get regular unleaded in our area any more, so use 95 premium for 2 fills then a 3/4 with E10, then repeat the cycle. I get noticably better fuel economy with 95 premium compared to E10

    • in my 98 fairmont i find E10 awful, ord unleaded is good but i find the shell v power the best, smoother starts, smoother running and better fuel economy

  5. Hi

    I have a 1983 XJ6 Jaguar, it runs happly on unleaded without additives as it has an alloy head with harded valve seats, but as there is no recommended unlead fuel type for this car, can yiu tell me what would be the best to use ( I will not use E10 )

    • I have a 1984 XJ6, 1989 4WD & a 2001 4WD, all run better on 98.
      Cars approximately 10 years & older, have materials in their fuel system that are not compatible with blends of ethanol. Tank, fuel lines, seals in metal, rubber & plastic have to be of a material that doesn’t swell, break down, or corrode. Just ask someone that specialises in fuel systems!!

  6. I have a 2005 Corolla for the first 3 years I used unleaded and kept full records of fuel consumption I tried 1 tank of E10 and the car was sluggish and used more petrol, so straight back to unleaded. The service station I go to has now droped unleaded and has E10 which I now use and notice there is no difference in the performance of my car.
    I have been told E10 if in the service station tanks to long build up a water content and that is what causes the most of the problems in cars

  7. Have given up using E10 in our 2008 RAV4 , and now using premium 95 and 98, the vehicle now runs smoother, more power and better fuel consumption.

  8. I’m a little worried about E10 fuel, but not in a way that you think. Is it safe to use this in two stroke engines? Regular unleaded will disappear in the near future and I want to know if E10 should be used or do I switch to 95 RON

  9. I use shell v power 98 an Awesome fuel tried a lot fuels over the years and found this one the Best for fuel Consumption Power ect Juct go to the shell v power site and have a read its all true’ Great stuff

  10. My 1996 Corolla runs OK in E10 so does my 2000 Hiace – however I was horrified to discover when on a campervan trip to NT and WA that fuel consumption increased by 20% with the Opal unleaded petrol – have others experienced that?

  11. For those who complain about E10, ask yourself what the oil companies are putting in that 90 percent gasoline. Consumer fuels are vastly differant then test fuels and the oil companies are making a cheaper gasoline today as long as ethanol is added. Octane does matter in many vehice’s but this varies for many vehicles like computer programming, carbon build up and engine/vehicle weight ratios.

  12. While my Ford Territory has a recommendation of Unleaded, using 95 or 98 brings my consumtion down from 16/100 klm-12.5/100klms.
    Our 91 Pintara run more smothly on 95.

  13. Mr brother put e10 in my 40hp Yamaha 2/. within 20 minutes the fuel system gluged up an boat stopped. $300-00 service later and it was fixed. Never again.

  14. I don’t have a choice. My two cars are of 1990 and 1994 vintage. No E10 permitted for them. So automatically my fuel costs go up by 20%. How paternalistic of the government. I’m not so sure the environmental benefits are so great anyway.

  15. Lately there have been many advsrtisements from oil companies about the benefits of premium petrol. But from the original post by NRMA, normally there are no benefits from using a higher octance fuel. On the other hand, some people, including those who posted a few of the blogs, have found improvements in fuel consumption. But is it true, as the oil companies claim, that premium fuels result in cleaner engines?

    • yes it is, when i got my 96 barina with the 1,4 throttle body injection engine
      it had black soot clogged up in the throttle body housing and what not – so we cleaned it out – I have been running premium ever since and 6mths down the track I decided to have a look how clean it was and what do you know – it was the same as the day we cleaned it

  16. Pingback: LPG – would you convert? | NRMA Motoring Blog

  17. I have been using E10 only on my falcon ef 1994 model which has 137k for the past 7 months and i havent had any problems at all. It actually smells better as well. I did notice high consumption for about 2 weeks after changing the fuel filter ($25).

  18. i own a 1983 XE falcon 4.1 wagon , and i’ve been told that i should run it on 98 octane because it has an alloy head .
    is this true , or can i use 95 ?

  19. Hi Steve

    The early Falcons and Kingswoods were designed for 98 or 97 octane, so you should use 98 with a valve protection additive. Some independent fuel retailers sell premium petrol with 10% ethanol in it, so avoid these, as your Falcon (in fact, all pre-1986 manufacture vehicles) is not suitable for ethanol.



  20. Hi Jack, my wife just purchased a 2013 bmw 116i , if I run 98, will it do any harm to the engine?
    I ride a 2007 honda cb900 , when I used to put reg unleaded it would ping its head off. I run 98 in it but never tried 95. The dealership who sold me the bike said not to run 98 as the additives will harm the injectors . Is there any truth in this?

    • Hi Franco

      NRMA advice is to use the recommended octane fuel for any vehicle, which is 95 for the 116i. You can use 98 but you won’t get any significant benefit, as the engine is optimised for 95. For the 900 again use what is recommended in the manual – if 95 is recommended you won’t get any significant benefit from 98. All petrol has detergent in it to help keep injectors and valves clean and, since the introduction of unleaded petrol, NRMA has not received any complaints of engine deposits needing to be removed.

  21. I have a Dec compliance 2008 Nissan tiida and wants to know if I can use 91 orE10 , since I bought the car I use 95 or 98 and Sometimes use 91. I want to know the recommend fuel for it ! Thanks

  22. Hi I put in my ford falcon 2000 instead of 95 unleaded 91 unleaded wich is for 1982 car and my car shaking how bad ia it how can I empty the tank by myaelf

    • Hi Simon,
      If you believe that you have mis-fuelled your vehicle, or simply have obtained a bad batch of fuel. For reasons of safety alone, you are best advised to have the vehicle towed into your local mechanic, where they will be able to correctly remove and drain the tank. Best wishes, Matt, NRMA Motoring Advice

  23. Hello,

    I am using UL91 in my Toyota Corolla (2001). Someone suggest me to use UL98 occasionally to clean the engine. I am not sure whether this is true. Could you kindly advice?


    • Hi Abdullah,
      When it comes to fuel requirements, it is vital that the manufacturers requirements are satisfied. With that in mind, there is nothing wrong with exceeding the fuel requirements through using premium grade 95 & 98 octane fuels. Depending upon your engine, you may or may not notice a difference. Simply call 13 11 22 and provide your NRMA Membership number if you’d like any more Motoring Advice. Best wishes, NRMA Motoring Advice team

  24. Hi
    I’m driving ford focus 2007. Previously my brother own this vehicle. He always use BP ultimate 98 so when I took the car from him he told me to use same fuel to keep the engine condition right..! My Q is what kind of fuel for my car will give me good service and should I really have to use BP 98(bit xpensive!) or any other retailers 98 is same as BP 98 and will get same benefits…. Thanks

    • Hi MJ,
      First and foremost, its vital that you consult your owners service manual regarding the fuel requirements for the Focus. Due to some Ford Focus models being turbo charged, you may be required to use nothing less than PULP 98 grade.
      The reason for Premium grade fuels is that they are of a higher octane, containing cleaning agents that also ensure cleaner internal engine componentry over the longer term. However, it is also important to consider that an engines extended service life is also contributed to by its level of servicing.
      Hope this helps,
      NRMA Motoring Advice

  25. Sometime back I check the web on compression ratio of year 1977 opel kaddet that i sold in 1990. Its say compression ratio of 7.8. If I were to use RON95 or RON 97 gasoline it will certainly be waste of money. From the web it seems that by 1985 most engine compression had gone up to 9:1. By 1995 gone up to 10:1. Nowdays new engine compression ratio is 10.3:1 or more. Funny is that all motor journalist and car brochure failed to state what is the RON or octane number of gasoline used during the duration test drive or during the runs for the production EPA urban or highway milage figure. I would give a wild guest that RON97 gasoline might able to give extra 5% milage, per litre wise, over RON95 gasoline for my honda jazz engine year 2013.

  26. Hi there, just wondering if someone could help. I just bought a 2008 mitsubishi lancer es 2.0 litre. I been puting 91 octaine wat petrol does it require. Thank you

    • Hi Labi, information available to us suggests that the model in question is suitable for use with standard unleaded 91, which may also be confirmed within the owner’s manual. Hope this helps, Daniel, NRMA Motoring Social

  27. Cant believe how many people didn,t stay awake when they were learning English at school, I have never seen as many spelling mistakes in my life ! Seems to be viral !

  28. I have a2004 Ford Escape and my manual justs says to use unleaded petrol I have been using 95 but I put 91 in by mistake and it almost cut out while driving and had trouble driving it stopped at first garage and topped up with 95 but the engine light hasn’t gone off

  29. High octane fuel does benefit cars with fuel injection. Firstly the computer recognizes the difference over the standard fuels. My car is designed to use regular Ron but I use 98 Ron octane. The difference is 500 km 91 ron per tank full of std octane and 645 km on high 98 octane fuel per tank full. For me that speaks for itself and the cars computer gives me this information. My cars computer detects and adjusts itself to the parameters of different fuel. Of course you pay more for the high octane stuff but i don’t care about that. I just love the great power gains in kw-ts that it provides. Its great stuff 98Ron premium fuel and is great for my car.

    • That is the most ridiculous claim I have seen so far. There is no way you are getting that much improvement with 98.

      • I think some people are less concerned what their car manual recommendation is and are tempted to associate fuel price with performance. A car manufacturer has vast resources to research, test and recommend you about the fuel type than anyone else. Just read the manual. Cheers!!!

  30. I own a 2002 Mitsubishi Mirage and I was wondering if I’m able to put 95 octane into the fuel tank. Is it possible to do this? If so, will it cause any harm?

    • HI Aaron, Using a higher octane fuel than designated for a model is not going to harm to your engine , except to your pocket! It is worth noting that there are no technical advantages gained from its use in cars without an octane sensor, as is the case with your model. Also any extra kilometres per litre gained is offset by the extra price of the higher octane fuel. Please give us a call on 13 11 22 if you need any further advice. Cheers, NRMA Motoring Advice Team.

  31. Hi i was wondering if my ford falcon wagon 2006 would benefit from premium unleaded and if so which one should I use?
    Thank you

    • Hi Elizabeth, given that the 2006 Falcon features a higher internal compression ration of “approximately” 9.7:1, by running your car on either 95 or 98, you should notice a difference in all-round performance. Best wishes, NRMA Motoring Advice

  32. Hi
    I have a Mitsubishi Express Van 2007 Model…..it has poor acceleration from a start when using unleaded 91 so I have started to use Unleaded 95 which seems to be mush better but I now have a engine fault light code P0421 which is (I believe) slow warm up of the cat converter – the van runs okay on Unleaded 95 ……do you know which is the best fuel for this vehicle for performance and economy

  33. Hi John. According to information available your vehicle is capable of running satisfactorily on standard unleaded petrol with a minimum 91 octane rating. Therefore the cause of poor acceleration you mentioned is unlikely to be related to 91 octane petrol use. Any improvement in performance from using premium fuel is offset by its cost. We suggest you contact your dealer/dealer to investigate the reason for poor acceleration. Best wishes, Neville- NRMA Motoring Advice

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