Blue Albatross
In the spirit of info sharing so you can make the best decision for your situation and location let me say the following.
My previous post along with this one is based on North America, mainly US manufactured fuel. The Major Oil Companies formulate and operate their refining differently in each country, even if they share a common name.
Shell USA vs Shell elsewhere, BP England vs BP USA
Avgas is manufactured using olefins and isobutane in the presence of sulfuric acid or hydroflouric acid. It is mostly stable as far as gumming and generating unwanted carbon deposits. Also not usually harmful to silver components in engines.
Mogas is made from a molecular cracked feedstock. This makes it necessary to add antioxidents, caustic, butane etc. It is less stable as far as gumming etc. Throw in oxygenates, Reformulated gasolenes, Aromatics and Mogas can have extremely different compositions from the same Brand in different countries. Not to mention independent dealers.
Mogas and Avgas can have vastly different vapour pressures, freezing points and octanes
Also Avgas does not contain Aromatics. Mogas does. Aromatics are destructive to elastomers.
On jet vs diesel...spec. on jet (non combat) is -40C freeze. Diesel is the point at which it gets hazy, called cloud point 10F.
Only you can determine how any of this applies or does'nt apply to your situation, geographic location and your individual plane's STC.
I would hope all of the above is considered by Aero Companies and Regulatory Agencies prior to STC approval. That way if you flyover here on your Mogas you can get back on ours!!
