Avgas question

meathooker · Nov 2, 2008

last weekend i was at my friends house whos dad happens to be a crop duster pilot. we started talking about avgas prices and being used in two strokes (turbo) and he didn't think that it would work very well. he told me that av gas is designed to vaporize at a higher temperature than regular gas b/c it is used in air cooled applications. I guess air cooled cylinder temps are significantly higher than a liquid cooled motor and the avgas vaporizes at a higher temp to aid in cooling (redundant i know).

does this sound like correct information?

Carl

06MXZXRenegade800 · Nov 2, 2008

Not entirely.

Avgas is subject to much higher standards of quality which is why you 'cannot' use automotive gas in an airplane.

Avgas actually has a lower 'vapor pressure' than automotive gas which also helps prevent air in the fuel system resulting in vapor lock. Which, makes no difference running it in any other application other than the reduced probablility of vapor lock.

Avgas does have a higher boiling point than pump gas. Not sure really what the difference would be other than a loss of power compared to something with a lower boiling point.

DRD · Nov 3, 2008

This gets talked about every year it seems.
There's generally is two sides. Those who have used it and had no problems, those who don't like it because their cousins, uncles friend blew up a chainsaw 12 years ago so it must be bad.
I've run it in everything from my triple that made 197 HP at 9300 RPM to year old stuff in my weedwacker with no problems.

T-BO · Nov 3, 2008

Is avgas leaded? Does it have a higher O2 content that pump fuel which would require rejetting to run without melting down?

06MXZXRenegade800 · Nov 3, 2008

Yes 100LL (most comon avgas) is leaded (hence the LL-low lead), it will have a maximum of 2grams/gal

The 100/130 avgas has a max of 4grams/gal

Avgas has a density of 6.02 lb/US gallon at 15 °C, or 0.72 kg/l
The density of gasoline is 0.71–0.77 kg/l (0.71–0.77 g/cm3),(in English units, approx. 0.026 lb/cu in or 6.073 lb/U.S. gal or 7.29 lb/imp gal)

Regular gasoline is a little more dense, but as far as the actual o2 content goes, that really depends on where you live as different places may have different blends of gasoline.

BigBoreManiac · Nov 3, 2008

My limited research suggests caution if using any leaded fuel if you are also using an AFR as the lead destroys the sensing probe.

06MXZXRenegade800 · Nov 3, 2008

The cheaper o2 sensors will not last long at all if you are going to be using leaded gas (Avgas or race fuel). But their are some much more expensive o2 sensors that are supposed to hold up a little longer...

turbo800 · Nov 3, 2008

Which has more lead AvGas(100LL) or 110 race fuel?

av8er · Nov 3, 2008

avgas

Mxzx is partially right avgas does not have a boining poit, it has a higher flash rate, yes it does have lead, I've been running avgas in my sleds for years with no problems what so ever, avgas weighs 6 lbs per gallon, and is better to run in modded sleds due to it's flash point, 110 octace race fuel also has lead in it probably more than 100low lead, I've also been a pilot for 16 years and have used it alot, even in airplanes such as amy avatar pic, But it is expensive usually around $5-$5.50 a gallon

Modedmach1 · Nov 3, 2008

av8er, do you fly for Neptune INC??? I used to work for H&P in Greybull as a mech.

Avgas question

meathooker

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06MXZXRenegade800

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DRD

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T-BO

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06MXZXRenegade800

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BigBoreManiac

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06MXZXRenegade800

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turbo800

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av8er

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