XC70 Regular 91 RON or Premium 98

RomerJon17ansett.747 (@RomerJon17) Frankston, Melbourne
edited August 2019 in Troubleshooting

My parents bought a used first owner XC70 2003 Volvo AWD Turbo Cross Country. I checked on the manual and I see it uses RON 91, 95 and 98.

The manual recommends to fuel the car with 98 Premium which cleans the engine. I called Masons and they said you can use RON 91 because it doesn't harm the engine but the previous owner use Premium 98.

So, should I allow 98 to keep the engine clean or use 91 to save money but builds up the dirt.

VOLVO XC70 2003 AWD 160,000KM



  • I think the cleaning of the engine using high octane fuel is a marketing ploy to get you to buy it.

    Don't believe what the petrol companies advertise. It doesn't work

    You're wasting your money with high octane in that vehicle, 91 works fine and actually nets better fuel consumption - it burns faster therefore needs less to consume, and provides better engine response than a higher octane in an engine deemed as low performance which ends up being wasted

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    In a 5cyl turbo Volvo you don't use 91.

    95RON minimum.

    You will notice better fuel economy,more power and better driveability.

    If you want it to roar, 30% E85 and 98 RON makes it growl. I've had a lot of turbo 5cyl Volvos. My 6cyl loves good fuel too.

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    And I really don't understand the 91 uses less fuel. Maybe because ed the engine is knock sensor limited to almost limp home mode.

    I hear so many cars about me knocking on take off. This 91 fuel is destroying engines and they don't notice.

  • What's the compression ratio of your 5 cylinder turbo engine snoopy?

    It matters not if the engine has a turbo or not, fuel doesn't care how the engine is aspirated, and I promise you if you filled up your car with 91, you will not hear any knocking sounds. Try it

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    Our 91 is probably 85 euro ones so way below manufacturer spec.

    I have tried it,it's crap,low power,more fuel use.

    Simple,spend a few dollars more for better result,it really isn't much more per tank.

  • SpacSpac (@Spac) Canberra-ish.

    In various whiteblock turbo Volvos, we have consistently found that the improvement in fuel economy makes 95 octane fuel cheaper than 91. IE: The improvement in economy more than outweighs the extra cost at the bowser. Performance is noticeably better too.

    In some of them, 98 octane petrol makes enough of a performance/economy improvement to be worth the extra price of 98. This is not always true, and depends on the exact vehicle.

    Honestly, the only way you'll know is if you try it. Put a couple of tanks of each fuel through the car and see what you find - keep track of the economy on the second tank because it will take a while for the ECU to adapt to the different petrol and settle down enough to give you reliable figures.

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    Yes,true,98 can be of no benefit in circumstances.

    I find some 95 works well too.

    I still love the extra kick 30% of E85 gives though.....

  • Our 91 is the dirtiest in the OECD, second only to MEXICO!!! You'd be nuts to use it in a Turbo engine.

  • 98 ALL THE WAY , even in the lawn mower , mrs put 91 in the tt once as the station did not have 98 . Couple of miles down the road the coil packs spat their dummy out . Lesson learned .....

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    150ppm of sulphur in 91......

    Yeah, great stuff.

    Not only bad for car but the health of growing children and compromised adults in busy city centres, as if diesel wasnt bad enough around town.....

  • I recon the answer to that is don't sniff exhausts lol . But seriously what type of car uses 91 ? I've never used it. .

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    The nimbys taking over the working class industriall areas in Melbourne's inner west are all up in arms over truck emisions yet probably never service the car and use 91.....

    I hear so many small commuter cars going around that are pre detonating,pinking, giving the motor an early death. Imagine the ECU would max out richness so even worse emision?

  • Not to mention the sulfur wrecks O2 sensors and cats so the emissions get worse with time... also wrecks the oil which worsens engine wear.

  • There's tons of cars that are tuned to run on 91 (4 out of 5 in my family for a start - only the Volvo isn't). I expect my Liberty (bought second hand at 9 years old and 115,000 km) was always run on 91. It's smooth, quiet and sweet running. Prove much? No, it's a sample of 1, but I suspect most cars that are tuned for 91 from factory are run on 91. Most seem to last just fine.

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.

    As the article says,lots of manufacturers define cars for here or don't send the best tech motors here at all cos numnutsput 91 in when it's 95 at minimum.

    And really,a few dollars a tank? Why use a bad fuel....

  • Sorry I have to step in and say it, you don't know what you're talking about regarding this topic

    If 91 octane was as bad a fuel as you say it is, it wouldn't be made and sold

    Remember we're not discussing E10, this is 91 regular unleaded

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.
    edited September 2019

    Read the article...........

    And why the personal attack brother,tone it down.

    Read the article.

  • I agree with @Ex850R you can hear the ecoboost ford/volvo and vw/audi/hyundai direct injection turbos pinging in traffic from using the wrong fuel. Often the owners have no idea they're using the wrong fuel until it blows the ringland off one of the pistons.

  • not only newer stuff either, my 28 year old peugeot specifies 95RON minimum.

    it'll run on 91 but by gosh don't you know about it, bad idle, won't rev out smoothly etc

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