You need more information.  Mogas comes in 87, 91, and 93 octane.  100LL is,
of course, 100 octane.  Mogas can also have alcohol mixed in at usually 10%.
If you put alcohol in your wing tanks, it could melt them, so you need to
ensure that none of the Mogas has ethanol in it.
What engine are you going to run this in?  some low compression engines
would not mind the low octane.  Others will not like it one damn bit!
Turbocharger will definitely want the higher octane!
You can do a lot of damage to your plane with the wrong fuel.

As Davy Crocket once said, "Be sure you are right, then go ahead."

Bill B

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Danny
Miller
Sent: Thursday, September 23, 2010 5:24 PM
To: lml@lancaironline.net
Subject: [LML] Avgas & Mogas mix

I heard through the grapevine that a mix of 2/3 mogas with 1/3 avgas is a
viable mix for most LNC2 types.  Does anybody have experience with this?

Danny Miller
N 38° 43' 27"
W 77° 30' 38"