Another note about one of the post's above:

First, is the homemade mogas that EZflap is talking about an FAA approved method for use in a certified airplane?

I certianly don't want my insurance company to find out that I'm making somekind of homemade fuel. What if something happened and the engine quit for some odd reason (even if it weren't a fuel problem)? Then the investigators find some kind of mogas that wasn't handled properly, or the insurance company found out that I had went through the process of seperating the ethanol from the gas or whatever. I think your opening the door for problems down the road (if something bad will happen). Trust me, from the storys I hear from other pilots that have dealed with there insurance companys in the past, they (the insurance company) will try every thing they can to not pay a claim.

Do what you want, be careful and make a smart educated decision yourself. But I'm going to stay away from the homemade mogas thing. Might be a good idea to talk to your insurance company about this if you plan to try the homemade mogas route. I don't know, just my opinion.

I use Mogas 87 Octane (mid grade) in my 150 whenever I can. The engine was designed to run 87 Octane so that is what I use. My mechanic hates Mogas and is always trying to convince me to run Avgas. I have Blackstone Labs do oil tests on my 150 and they told me that if I quit using Avgas, they would be able to watch my bearing wear. They also told me my engine looked to be in great shape.

I do like to keep a little lead in there because the old engines used the lead to lube the valves. When cars went to unleaded they started using hardened valve guides. If they made 87 Low Lead again I would use it exclusively.

Jerry

The small Continentals are certified for 73 octane gas. I'm not sure about the O-320's but I know they ran all day long on the old 80/87 fuel with no problem at all.

If removing the alcohol from REGULAR car gas lowers the octane too low, the start with 89 or 91 octane and you will probably still be over 80 or 83 when you're done.

If you absolutely must, you can put some octane booster like 104+ in the gas, but it probably won't be needed for low compression engines.

58Skylane wrote:
First, is the homemade mogas that EZflap is talking about an FAA approved method for use in a certified airplane?

I certianly don't want my insurance company to find out that I'm making somekind of homemade fuel.

Absolutely it would be wise to check with them. But instead of telling them you are home-brewing your gas like moonshine in a backyard Hillbilly laboratory (which they will automatically have an issue with just by the sound of it), ask them if the insurance covers an airplane with an auto gas STC and using automotive fuel that either has no ethanol in it or has had the ethanol "filtered out".

If they say "no you are not insured if you filter out the ethanol", then that is your answer. If they say "as long as it meets the requirements of the STC you're OK" then you're OK.

The best thing to do would be to contact EAA or Petersen and ask THEM if their STC is valid for car gas that has had the ethanol removed. If they say that the STC is valid no matter how you got ethanol-free gas, then you should be OK.

Mongo wrote:Has anyone had any issues in mixing 100LL and Mogas?

I'll add 25 ga 87 octane car gas to my 55 ga drum then top it with 100ll. My fuel supplier here in Ca says that the ethanol is 6% in car gas so breaking it down 50% is 3% ethanol? Works good for the O-470K.

This might be a little off topic. But according to Airnav.com great deals page for fuel. The cheapest fuel advertized on the site is at http://www.airnav.com/airport/4F2 for $2.95 a gallon!

The two runner ups at $3.00 a gallon:
http://www.airnav.com/airport/KHBR

http://www.airnav.com/airport/14J

Then one at $3.05 a gallon:
http://www.airnav.com/airport/KRCM

BRD wrote: ...... so we have "off road / collector car only" ethanol free 91 octane pumps in many locations. .........150 hp O-320's are designed for 80 octane fuel.....

That ethanol-free 91 octane would be a perfect solution, I wish they would make that an option nation-wide as they force 10% ethanol regular on us. They could ethanolize all the 87 then & it wouldn't bother me ( not too much anyway).
My Lyc 150 is approved for 80/87 minimum grade, not 80. Not sure of the difference,but i do recall reading years ago that cargas & avgas use different methods to rate octane. I wouldn't trust "distilled" 87 octane gas, or 91 either, as I don't know how much octane boost comes from that 10% ethanol.
Keeping my fingers crossed on availability...

Eric

as I don't know how much octane boost comes from that 10% ethanol.

About 2 to 2 and1/2 points per 10%. Around here some pumps say 89 oct and some 89.5 oct. I don't think anything less than 87 is flowing up the pipeline into NW Iowa before being blended.

I know several guys in my area that have been using 91 octane car gas with no alcohol for 20 years + in both Lycoming
0-320's and Continental 0-470's and they have had no problems at all. 91 octane in our state does Not have alcohol in it !The 91 Octane is made for antique cars, lawn mowers,tractors etc. It does cost 20 to 25 cents a gallon more than the regular car gas with alcohol. One pilot does mix his 91 octane with 100 LL just to keep some lead in the mix.