Mixing Avgas and Mogas for Subaru Ops

dunc

RAF/Sparrowhawk/SC 2.5 FI
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Aug 1, 2016
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164
Location
Crawford, CO
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1967 Turbo/RSTOL/VG Cessna 185 Skywagon, 1946 Grumman TBM Avenger
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Who does it? Why? Proof?
 

AirCommandPilot

Just a fledgeling
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Feb 24, 2014
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Houston
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Air Command Elite #003
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Explain? Are you asking if it's possible, preferred, or if it's normally done? I've got a Subaru and would like to know also.
 

Kolibri

FW and Gyros
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Oct 17, 2014
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Wyoming
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Cessna 152, 172, 172RG, 177, 206 -- Piper 180 -- RV-7A -- Calidus -- RAF2000 -- Sport Copter II and
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1000+
I use no-Ethanol 92 car gas from my hangar, but if x/c the airports almost always sell only 100LL.
So, a mixture of the two is inevitable if you travel in your gyro.

If you use 100LL in any amount, you should also be using at least a semi-synthetic motor oil, if not a mineral-based oil.
Pure synthetic oil will not capture the lead deposits of 100LL, and will actually sludge up.

That said, I see no value in purposely mixing them, and some possible detriment to doing so.


https://www.rotaxservice.com/rotax_tips/rotax_feed4.htm
https://www.fuelexpert.co.za/canirunavgas.php
https://www.rotax-owner.com/en/rotax-forum/3-4-stroke-technical-questions/4490-risk-of-use-of-full-synthetic-oil-with-100-ll

Tip: use a quality semi-synthetic motor oil, and you won't have to wonder if it's OK with which fuel.

Regards,
Kolibri
 

dunc

RAF/Sparrowhawk/SC 2.5 FI
Joined
Aug 1, 2016
Messages
164
Location
Crawford, CO
Aircraft
1967 Turbo/RSTOL/VG Cessna 185 Skywagon, 1946 Grumman TBM Avenger
Total Flight Time
5000
Thanks for the cited tips, Kolibri. I assume anything good for a 4 stroke Rotax is good for the Soobee too, I may have been given some bum information by well-intentioned experts. Getting quite comfortable now, flying about an hour each day, mostly S&G. Will start practicing aerial maneuvers soon, and having a blast. That cabin heater works pretty well.
 

L_Butler

N41423
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Nov 18, 2003
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278
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Dillinger's Station, PA About 10 miles south of Al
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J4B2 N41423
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The lead in the aviation fuel will foul your oxygen sensors used by the computer to inject the proper amount of fuel. I have heard of people using TCP to bind with the lead and prevent this from happening, but I don't know if it really works. My subaru has fouled a sensor using avgas. It runs really rich and gas consumption is horrible. It gets worse the higher you go.
 
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