Reply With QuoteI have heard that av gas is formulated to burn at altitude.??????? less oxygen as the alt goes up.
lets see what u guys think on these two fuels... and what advantages or disadvantages are there when running av gas..
I have heard that av gas is formulated to burn at altitude.??????? less oxygen as the alt goes up.
i have also heard that some av gas have de-icers in them and they can gum up jets if let sitting for too long.
I believe both are not quite correct. If you will remember some aircraft have a fuel mixture adjustment. Some aircraft are turbocharged, and the ones that aren't generally do not fly that high anyway.
AV gas is formulated so they do not vapor lock at altitude, but that is not the same as deicer. AV gas does not need a deicer, which leads to another misconception or misstated assumption, I have heard that it is a dry gas and needs oil added to it. AV gas is a dry gas, meaning the water content is controlled and very low. Another misconception is that the gas is made for slow running motors. Burn rate is controlled mainly by the air-fuel ratio and compression.
AV gas tends to gum up less than most gasolines, it actually keeps for long periods. This as opposed to what you buy at the pump and hope it hasn't already gone bad or is loaded with water.
AV gas is a very controlled fuel and poor quality is not something wanted in aircraft.
If you are looking for a little octane boost it is OK to mix a little av gas, like 50/50 with 93 octane.....You really can't compare it to actual race gas. You also can't read any color on the plugs for tuning purposes. As mentioned, av gas is very dry and not designed for automotive type engines, and the addition of some Marvel Mystery oil is a good idea. I think it is like 4 oz to 5 gal........Spend the money and buy the race gas.......you'll be happier in the end..........MP
I ran a 855 HP 10.8:1 compression engine on a mixture of 2 parts Av gas 1 part 92 pump gas for years. Never had a problem. It's not race gas,but it's not bad either. I have a friend with a 13:1 BBC and just runs Av gas out of the pump at Fishers. It runs just fine.
Sleeper CP
I have run AV gas for many years without any problem. My previous motor was 540 BBC, 2 Dominators, Pro One heads, 12.2 compression. Motor looks really good at rebuild.
Finishing up putting a 14-71 blower on same motor with 9.2 compression and will use AV in it.
The dry part of the gas does refer to water content.
AV gas is not a substitute for many of the race gases, I do not know what the limits of AV gas are but I would go 12.5 or maybe a little more. The octane is 100 - 110. The airport can provide exactly what it is.
In regard to the oil being added, I am curious if propane or natural gas has oil inserted when it is used in a car.
I know and have talked with a bunch of people who run av gas and have never heard of a problem.
im running a 468 BBC 13.5:1 i wonder how the enging would run on av gas. ive always run c-12.
i have a 9.1 motor with a 150 shot going to put 200 on it and the book states anything over 150 i need race fuel.:idea: they also say under no circumstances to run av-gas whynot saying i need it with my motor but thought i might mix it just to be on the safe side but they are very much against it.:devil: nx hitman kit is what i have.the airport is 2 miles from where i live and they have 100 octane fuel pretty cheap but i dont want it to damage anything:jawdrop:
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