New fuel standard for 912iS? (again)

I’m new to this site so sorry if this is a duplicate question. I’ve got a 912is in a Flight Design CTLSi

Can I use automotive gas ( is that Mogas?)

with or without ethanol and what would be the minimum octane?

how long can I leave the gas in tanks before a problem with it going”stale”

Any issues with blending 100LL WITH the automotive fuel?

Click the SUPPORT/BULLETINS Tab above to Review the latest Service Bulletin 

MOGAS,  Yes!  Premium AKI 91 Octane or more required. 
Up to 10% Ethanol OK!
Mogas and 100LL mix? Yes!

Stale Gas ???
A couple of Months should not be a problem.
You will hear arguments that vary from 1 Day to 2 Years.
Let's not open THAT Can of Worms.

All Flight Design aircraft can use auto fuel. 91 oct. and with ethanol. Our tanks are coated to seal against any effect from the ethanol and no more ethanol in the US it isn't an issue for aircraft or engine. Most of the CT's in the US use auto fuel with ethanol.

the question of how long is the fuel good before going stale...  According to the fuel companies it will depend.  For fresh fuel without ethanol it is supposed to be good for 6 months.  If it has ethanol the time is cut in half to 3 months.  In reality you should most likely consider a shorter time.  Should you live in a region where they change the blend from winter to summer fuel then be very careful to never use winter blend fuels in summer (hot) weather.  

The good part to know is that blending auto fuel with Avgas works just fine.  if you are unsure of your fuel storage time top up with Avgas.  The Avgas has a high percentage of toluene and that will look after gum deposits.  The 100 MON octane of Avgas will bump up your old auto gas into a more suitable range to prevent detonation that is possible with very old fuels.  

Someone asked about Swift UL94 (94 octane MON) .  While it is not approved by the FAA and is sold by Swift under the ASTM standards for unleaded Avgas it is high enough in octane in any of the Rotax engines.  They do not make a winter blend so the RVP is stable.  In any event the OEM should do testing to verify any auto fuel for vapor lock issues.  In Particular is the hot engine soak test, most know this as the short turn-around where the engine was flown and then lands sitting on the ramp for perhaps 30 mins.  On takeoff fuel from the hot soak on the ground may have caused vapor to form in the fuel lines, fuel pump or any other area within the engine bay.  The iS will normally show a lot of vapor formation on the return line and if that is picked up by the fuel feed inlet you might have problems.  This is why the OEM needs to test based on make and model of the aircraft, its not just an engine thing it is installation as well. 

Cheers