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  • Re: Fuel in Brazil

    by » 3 months ago


    Tyler, 

    First of all know that I am very grateful for your answers.

    I understand your concern, but if for here many people are using  gasoline with 87 IO  without problems (no increase in oil pressure, no increase in CHT, no decrease in EGT, ......) on the rotax 912.
    Wouldn't it be less problematic on the Rotax 914 to use this gasoline since the compression ratio of this engine is lower (9: 1) instead of the 10.1:1 of the 912?


  • Re: Fuel in Brazil

    by » 3 months ago


    The Octane Rating Article in Wikipedia reports...
     
    ... in Canada, the United States, Brazil, and some other countries, the headline number is ..., called the Anti-Knock Index (AKI),... (R+M)/2.
     
    The PetroBras Website seems to confirm this.- - -
    They are aparently adding some other inexpensive compounds that mask the Ethanol advantage in their "Grid" and "Regular" economy grade fuels.
     

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


  • Re: Fuel in Brazil

    by » 3 months ago


    The 914 engine may have a 9:1 Cylinder compression ratio, but the Turbocharger adds another 1.3:1 multiplier to that, making it closer to 12:1 in the final squeeze. 


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


    Thank you said by: Marcelo G Martins

  • Re: Fuel in Brazil

    by » 3 months ago


    Bill, thanks for your help.

     

    What do you think mix Gasoline Grid (87 IO) with Gasoline Podium (95-97 IO). In this way I have minimum 91 IO.

     

    Why I ask this? Because gallon cost in Brazil: AVGAS u$ 6.4 // Grid u$ 2.85 // Podium u$ 4.17------> Mixing Grid and Podium= u$ 3.5

     

    When you said me that Turbocharger add 1.3:1. I made a research looking for it and I found this attached. It´s that you talk about?

     

     

    Thank You

     

     
    26188_2_adicao de compressao.png (You do not have access to download this file.)

  • Re: Fuel in Brazil

    by » 3 months ago


    No, that chart is for fuel pressure.

    If you consider that normal ambient pressure is about 30"Hg and the turbo produces about 40"Hg,  40/30 = 1.33:1 Turbo Boost.

    And 9:1 times 1.33 = 12:1

    - - -

    You can mix the gas to adjust the AKI.

    Your Regular grade is the same AKI as the Grid grade, only without the additives and probably even less expensive.

    87 + 97 mixed 1:1 = 92

     

    If you have seperate fuel tanks, you could put 87 in one tank and use it for cruise when the MAP is less than 30"Hg.

    Switch to the High Octane tank when climbing or once you are approaching the destination.

    It will take a minute for the fuel to reach the carb and you will want to be using it long before the chance of a go-around becomes a possibility.


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


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