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Unleaded: 95 RON vs 97 Super.. is there really a difference!

  • 19-11-2004 02:37PM
    #1
    Closed Accounts Posts: 9


    Bouught a '01 Audi 1.8T (180) a few months ago; at the time the dealer recommended using super unleaded to get the best from the engine; now, I have been running it on standard unleaded -> but the question is;
    1) It's 25% more expensive (99c vs 124c/litre).. surely ye don't get a 25% increase in performance??
    Has anyone used super unleaded and notcied any difference?


Comments

  • Moderators, Politics Moderators, Paid Member Posts: 45,528 Mod ✭✭✭✭Seth Brundle


    AFAIK it burns at a higher temperature and gives better mpg
    read http://www.petrolgauge.com/ie/docs/faq.htm

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  • Registered Users, Registered Users 2 Posts: 6,536 ✭✭✭alias no.9


    It all depends on the car. High performance cars often benefit from super unleaded but does the extra performance justify the extra expense, thats subjective and up to the person paying for the petrol. You might find that you get better mpg on the super unleaded so thats something to consider if you're comparing the two. Ordinary run of the mill cars rarely benefit from super unleaded.


  • Closed Accounts Posts: 88,968 ✭✭✭✭mike65


    I can see no benifit except to the oil company. Stick with RON95 and be happy!

    http://www.boards.ie/vbulletin/showthread.php?t=114961

    http://www.boards.ie/vbulletin/showthread.php?t=165073

    Mike.


  • Registered Users, Registered Users 2 Posts: 31 sweeper4


    Bouught a '01 Audi 1.8T (180) a few months ago; at the time the dealer recommended using super unleaded to get the best from the engine; now, I have been running it on standard unleaded -> but the question is;
    1) It's 25% more expensive (99c vs 124c/litre).. surely ye don't get a 25% increase in performance??
    Has anyone used super unleaded and notcied any difference?

    You won't get 25% extra, but you will notice a difference. I am sure if you check the manual it mentions that Super Unleaded is recommended for the turbo engine. This is due to the higher compression in the cylinders (Under which the super unleaded performs better). With the better ignition in the cylinders you get more power - "more bang for your buck" in effect. (Or buck 24 in this case).

    The other reason the higher rated fuel is recommended is so you do not get premature combustion that is a (rare) possibility with ordinary unleaded under the higher compression.


  • Registered Users, Registered Users 2 Posts: 396 ✭✭pedro ferio-vti


    sweeper4 wrote:
    You won't get 25% extra, but you will notice a difference. I am sure if you check the manual it mentions that Super Unleaded is recommended for the turbo engine. This is due to the higher compression in the cylinders (Under which the super unleaded performs better). With the better ignition in the cylinders you get more power - "more bang for your buck" in effect. (Or buck 24 in this case).

    Well said, Super Unleaded won't make any difference on your average NA car. But if you're car is turbocharged then SUL will make a bit of a difference alright.

    Don't think the extra cost is justified here though, i'd buy some Silkolene Pro Boost octane booster and add this to the normal 95 RON petrol instead. At least you know you're definitely getting SUL.
    sweeper4 wrote:
    The other reason the higher rated fuel is recommended is so you do not get premature combustion that is a (rare) possibility with ordinary unleaded under the higher compression.

    Well, you're right in what you're saying but I wouldn't say it's a rare possibility. If the car has been tuned by the manufacturer to run on 98 or 97 RON (such as his car) and you're running 95 then the engine will be much more prone to "knocking" or premature combustion as you call it rather than it being a rare occurence.

    The engine will most likely have a knock sensor fitted to it and it listens for knock. If it detects any then it tells the ECU to retard the ignition timing which saves the engine from melting a piston or a valve but costs you performance as the engine will physically feel slower.

    Sorry for the long winded post......

    cheers
    Pete


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  • Closed Accounts Posts: 9 Father Hackett


    Thanks for the feedback!
    Manual does recommend 98RON. I dropped into a garage at the weekend which happened to have 'super' so I filled up.. 70 quid!!
    Driving it since.. it feel quick (but then it always was).. one thing though.. maybe I'm imagining it; both it does appear to be running smoother already (better combustion?).

    Will let ye know how it goes


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