From this website: http://www.afcee.brooks.af.mil/PRO-A...t/petfuels.asp

Aviation Gasoline Aviation gasoline, or Avgas, is the fuel used in aircraft powered by reciprocating, rather than turbo-jet or turbo-prop engines. Avgas is similar to conventional motor gasoline; however, there are several important differences. Avgas is generally less volatile and has a lower freezing point than conventional gasoline. Common additives to Avgas include alkyl-lead anti-knock additives, metal deactivators, color dyes, oxidation inhibitors, corrosion inhibitors, icing inhibitors, and static dissipaters. Three grades of Avgas are currently available in the U.S. and are characterized by their anti-knock characteristics. American Society for Testing and Materials (ASTM) Grades 100 and 100LL Avgas have octane ratings of 100 and are the most widely available. These grades contain about 1.0 and 0.5 grams per liter of tetra ethyl lead, respectively, considerably more than automotive gasolines currently in use. ASTM Grade 80 Avgas has an octane rating of 80, is declining in use, and contains about 0.14 grams per liter of lead.

Looks good to me. Less volatile means lower Reid Vapor Pressure which is controlled by the amount of butane (light ends) in the gas which is used to get Snow bird motors to start in the winter or "winter gas". Only thing is that there are usually corrosion inhibitors and sometimes oxidation inhibitors in ground gasoline also.

Not to mention, scary flammable. Obviously....Not worth the risk of fire or explosion, i have a friend who was seriously burned playin with it in his boat. Not worth the extra couple mph. Just put in a bigger motor.

been using it for years, no problems whatsoever, boat, dirtbikes, sandrail, hotrod, harley, always runs crisper than pump gas. I have heard there is a difference in the octane ratings and how it burns differently but all I know is I have been using it for years, and I know alot of people that use it as well and swear by it.:D

I wouldn't put it in anything that has an O2 sensor.

You can't put it in there, it'll ruin your catalytic converters......oh, nevermind :cool-smiley-011:

Used & sold it for years, had it for sale at my marina in Chicago until we closed in 95.

Prior to selling the avgas we would add tolulene in bulk (one of those light fractions mentioned previously) to raise the octane of the low lead.

At the time there was a lab in town that did octane testing. Aviation octane is measured differently that automotive octane. The 100LL if I remember correctly came in at about 105 using the R+M/2 (automotive) method (had some tested).

Not sure how it shakes out with E10, but according to Dr. Krawitz (I think that was his name) the resulting octane when mixed with 89 (or 93 for that matter) octane low lead is proportional, in other words if mixed 50/50 the octane would be no less than (89+105) /2 = 97. We used to keep a chart of the percentages on the pump.

I'm sure someone with a more technical background can explain better, but this is what I remember from back in the day. Did some real research at the time to make sure it would not bite me.

Good call on the oxygen sensor, I forgot about that. A problem with catalytic converters also.

haven't heard anybody talk about the issue of specific gravity. back in '79 my engine builder who was very conversant in building racing engines for airplanes jetted my carbs to run AV Purple; he told me to never run more thank 20-25% pump gas because of specific gravity issues (not sure what that meant now) of course one time I forgot and promptly put a hole in one of my pistons. Chris, or someone, re-enlighten us about this. - Jeff

I actually started to use Av gas in my winterization mix when I winterize engines. It doesnt leave moisture or residue in the fuel systems and electric fuel pumps of these new outboard engines. I got the idea from my Merc rep and it worked out great the past 2 years! I havent had a sticky or stuck fuel pump since I started using it.:D

AV gas 5.8 to 5.9 lbs per gallon pump gas 6.1 to 6.3 lbs per gallon

I will guess 550+ lbs of torque

I stand corrected, av gas is averaged at 6.0lbs per gal, jp4 is 6.5 lbpg, I seen a torque chart on aircraft engine's years ago, but do not remember the numbers, but they where very high torque value's.