AVGAS with stock motor/stock headgasket..what psi?

[Travis Moore]

I ran 10.5-11 psi this past weekend on strait AVGAS with no issues, so far at least. No signs of detonation on the plugs at all. Just curious if anyone else is running the same boost levels on AVGAS with stock motor and what your experiance have been.

Travis

 

[POWERHAULIC]

Many looooong runs at 12# with 100LL here

 

[Ted Jannetty]

What's the octane rating of Av Gas?

 

[Travis Moore]

What's the octane rating of Av Gas?

Thats a good question Ted. It's at least 100 MON, but some people say due to the diffrent rating scale for aviaton, that it's more like 104-108 MON. I figure it to be 100 MON, just to be ultra safe(like i always am with octane).

 

[BlgsRX-1mtn]

 

[Ted Jannetty]

Also note that AV gas is designed for High altitude conditions where you would need less octane anyway.

 

[Travis Moore]

Also note that AV gas is designed for High altitude conditions where you would need less octane anyway.

Yes, but where does a airplane need the most power? Takeoff, which is at normal altitude, and piston airplanes make the most power when the engine is set to 'full rich'. They lean out during flight for better fuel milage.

 

[crazy680]

Consider also.. there are many small piston engine airplanes that are turbocharged.. so even at high altitude a airplane can have a need for the octane that avgas provides.

I've been using it in my sled with no problems so far..

 

[TWIN TURBO]

I owned a Cessna P210 which is a large displacement 520 cu.in.6 cylinder turbocharged engine which was basically turbo normalized in other words take-off power was 36.5 in. manifold pressure about 2 or 3 lbs of boost., not a whole lot with 7.5:1 compression ratio. Anyway, avgas is rated 100/130 on most pumps meaning 100 octane with a rich mixture rating of 130. Like 2 strokes turbocharged airplane engines are fuel cooled. Avgas isn't exactly correct for auto,race, and snowmobile engines due to the fact its blended for higher altitudes with lower vapor pressures. I would stick with racing fuel if you can.