av gas

[patchesII]

are there any problems with runnng leaded 100 octane av gas at 40-1 on 150-160 lbs comp.tips on jetting, would jet fatter or lean in comparison to normal pump gas. thanks erik

[Firestarter]

Yes their is.
AV gas is the last fuel I would ever run in a 2 stroke.

If you have ever heard that AV "runs dry", the reason is that their is a chemical added to disperse oil. In an airplane a fowled plug would rather suck. In a 2 cycle oil is the life blood of your motor. This chemical dissolves it, over oiling will not help.
Your piston rings will last less than 50% of what they normally will.

RT

[Jay Smith]

Firewalker is correct,
It also has de icing agents that is not compadible with 2 cycle oil !

Jay @ JSRE

[mwarjone]

Av gas also vaporizes at a much lower temp because it is intented to be used at freezing temps. On a 100 degree day at the river AV gas is about like propane.

[Way2Fast]

Ever spill some.....blink your eyes and it's gone !!

[DSP1]

So what is the preferred 100+ octane fuel

[FCnLa]

It smells kinda like race gas. I have heard of people blending it 25 to 50%.

I think the reason the pump gas is like it is today is all the anti pollution BS that is in it. Seems like when I got gas on my hands 20+ years ago, the smell would go away. Now you could wash your hands in MEK after getting gas on them and the smell would still be there.

The only other alternative that I know is pure race gas or a blend of race / pump gas.

If I remember right...? the avgas may cause some oils (probably synthetic) to separate from the fuel. This would be bad-bad! Anyone else heard of this?

[Sorry Dog]

I kinda got a different read on the use of AV from a Prof OB thread. I'm going on memory but I thought he said de-icing agent is bad but 100LL doesn't necessarily have that, and also it was toulene that made it burn dry and that AV didn't have that but octane boosters often did. I forgot the location of thread in the archives or I'd check my remembering but here is a lengthy explaination that someone (sorry I forgot who you are) found:
http://www.cs.uu.nl/wais/html/na-dir/autos/gasoline-faq/part3.html

Damn where'd I but my brain pills I forgot to them today...

[fyremanbil]

Can't say much about use with synthetic oils. We never ran anything but AV gas in our MVP 2.4s in the 80's. Ran 40:1 with merc oil at about 7500 rpm. Used cut 2.0L heads. Dont remember the compression. Never had any problem, put hours and hours of WOT use on them at Parker Enduro, Havasu Classic, etc. Most of the privateers used AV gas just because it was the only reasonably priced high octane fuel available. When you run multi hour enduros @ 25 gallons an hour, it really adds up. I,m sure the big buck guys were using racing gas.
Bill