Mogas vs. 100LL?

Discussion in 'General Experimental Aviation Questions' started by TXFlyGuy, Aug 7, 2019.

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  1. Aug 13, 2019 #101

    Russell

    Russell

    Russell

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    We have mixed Swift fuel with mogas several times and then went racing ... full throttle for over 30 minutes. No known ill effects.
    Russell Sherwood
    Glasair IRG / Subaru EG33
     
  2. Aug 13, 2019 #102

    TXFlyGuy

    TXFlyGuy

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    Just been advised there is a phenom called "valve seat recession" that is a by product of running the leaded fuel in an auto engine. About a 20% chance of it happening.
     
  3. Aug 13, 2019 #103

    TFF

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    That’s good. I’m just regurgitating what the Swift fuel guys were saying at an IA conference. Maybe at the time they were being cautious.

    Valve seat recession is when running an engine intended for lead fuel is run with unleaded. I have never heard of it the other way. On an old engine that lead has been pounded into the seats for years tend to tolerate unleaded fuel without damage.
     
  4. Aug 13, 2019 #104

    TXFlyGuy

    TXFlyGuy

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    I must have gotten it backwards.

    Just found 93UL Ethanol free gasoline, about a mile from my house. The price? $7.00/gallon.
     
    Last edited: Aug 13, 2019
  5. Aug 14, 2019 #105

    spaschke

    spaschke

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    In Denver, ethanol free premium unleaded price is similar to 100LL price. And it is 91. can't get 93 here. I live near Bandimere speedway, the Mobil station has 100UL (pump marked as racing fuel) No price on the pump.
     
  6. Aug 14, 2019 #106

    TXFlyGuy

    TXFlyGuy

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    No price...must be free!
     
  7. Aug 23, 2019 #107

    TXFlyGuy

    TXFlyGuy

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    Question for you engine tuners...we plan to run both 93 E10 and 100LL. The ECU will be programmed for 93. Does this mean when burning 100LL the default program will be running rich, by maybe 5%?
     

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