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100LL avfuel


jc052685

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Dyed blue, 100LL, spoken as "100 low lead", contains tetra-ethyl lead (TEL), a lead based anti-knock compound, but less than the "highly-leaded" 100/130 avgas it effectively replaced. Most piston aircraft engines require 100LL and a suitable replacement fuel has not yet been developed for these engines. While there are similar engines that burn non-leaded fuels, aircraft are often purchased with engines that use 100LL because many airports only have 100LL. 100LL contains a maximum of 2 grams of TEL[6] per US gallon, or maximum 0.56 grams/litre and is the most commonly available and used aviation gasoline.

 

So any opinions on this fuel? Local cost is $4.15/gal. vs 93 @ $3.05/gal. I figure $1 more a gal for 100oct is a deal. Especialy with 110oct @ over $11/gal. Obviously its not DOT leagal.

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You may also want to also consider E85 if your fuel lines/pump can handle it. If I remember correctly it is ~96 octane so it may help if you are having detonation issues but your mileage will be lower. Availability may be an issue for some people.

 

I am interested in the opinion of someone more knowledgeable than me since I am also trying to decide what fuel I should be using. My motor has a high CR and I have to retard my ignition even on 93 to cut down on detonation. I was also considering 100LL but I had also heard that it has a tendency to ruin wideband sensors.

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You may also want to also consider E85 if your fuel lines/pump can handle it. If I remember correctly it is ~96 octane so it may help if you are having detonation issues but your mileage will be lower. Availability may be an issue for some people.

 

I am interested in the opinion of someone more knowledgeable than me since I am also trying to decide what fuel I should be using. My motor has a high CR and I have to retard my ignition even on 93 to cut down on detonation. I was also considering 100LL but I had also heard that it has a tendency to ruin wideband sensors.

 

E85 is 105 oct. Requires nearly twice the fuel flow. I am completely aware of E85 and what it can do. (see my 550whp integra for sale)

 

I am not talking about an alcohal based fuel I am talking about 100LL.

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All I know is that I worked at a F.B.O.(airport fixed base operator) for 12 years and ran 100ll in my 71 and it was the cure for my sticking valves and the car ran beautiful on it. Lead contact is very high even though it is called low-lead. The manager at my place wouldn't sell it it to anyone that didn't have a plane-maybe things are looser where your at.

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LOL, its self serve. I just show up with a few 5gal cans.

Yep. It's a big no-no to pump it directly into a car, but you don't have to be a pilot to buy it, so into cans and then into the car later. Of course it's also very illegal to burn it on the street. Every time this comes up someone pipes up about how planes run at 3500 rpm at high altitude and the specific gravity is different, blah blah blah. My personal experience mixing it with premium unleaded is that it works great. I did jet my carbs a bit richer.

 

Now though with the V8 I will have a bunch more hp and torque and my engine should run on 87 with no problems.

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Running avgas on the street is the same as boot legging, there are a bunch of taxes that don't get paid. But as has been said before the self serve is great with a couple of gas cans. I would reccommend doing it at night because you could get ramp checked by the FEDS, and if you don't have a real good story the next 8 to 12 hours of your life will belong to them.

 

Back in the 90's I worked at kvny Van Nuys Airport when Chevron had a distribution problem at one of their refineries and accidently mixed avgas with jet-A, every piston aircraft pilot was begging us to de-fuel thier planes, needless to say we had more avgas than we knew what to do with.

 

The only problem with running avgas on the street is prolonged idling in traffic will cause lead fouling on the plugs about every 3 to 5 k miles. Don't use expensive plugs and it wont hurt so bad.

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Running avgas on the street is the same as boot legging, there are a bunch of taxes that don't get paid. But as has been said before the self serve is great with a couple of gas cans. I would reccommend doing it at night because you could get ramp checked by the FEDS, and if you don't have a real good story the next 8 to 12 hours of your life will belong to them.

 

Back in the 90's I worked at kvny Van Nuys Airport when Chevron had a distribution problem at one of their refineries and accidently mixed avgas with jet-A, every piston aircraft pilot was begging us to de-fuel thier planes, needless to say we had more avgas than we knew what to do with.

 

The only problem with running avgas on the street is prolonged idling in traffic will cause lead fouling on the plugs about every 3 to 5 k miles. Don't use expensive plugs and it wont hurt so bad.

Easy way to get around that is to actually have an old lycoming or continental in your back yard. You're teaching yourself to work on engines on something simple ;)

 

zforce, can you tell me more about this lead fouling issue? Can it be 'burnt' off with some heavy right foot action, or does it necessitate pulling plugs and cleaning them?

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I'll admit it, I run a mix of avgas and super. It allows me to run my flat top F54/P90 turbo setup using the crappy stock ZXT EFI at 12psi with no audible detonation. Been going strong for 2000 miles with the same HG. I have found for my setup a 25% mix of avgas to super is about right and does not foul plugs even though I run two steps colder on my plugs. I could not run it straight. Changing the ratio of avgas to super had a big impact on how much fuel pressure I could run and how much I had to adjust the AFM to get it to run right. It still is not perfect, mainly because of the EFI system, but it is a good safety measure for me.

I am an aircraft mechanic, so getting a supply is easy for me. You will have a coating of lead inside the exhaust after using it for a while. 100LL still has alot of lead in it!!

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Yeah, it might take a little of both, but if you keep the revs up and don't run to rich it should be ok for a while. I fly a Cessna 172 that has a huge problem fouling plugs during taxi operations prior to take off, so I lean it out for taxi then set my mixture just before being cleared for take off.

 

When I was using the avgas in my Z with the stock engine it would foul pretty quick, but I think that was due to low compression ratio. If you are running high compression 11 or 12 the avgas will work better, avgas in a stock motor is useless but I love the way it smells when it burns.

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Keep in mind Aviation Fuel is designed for airplane engines running a fairly solid RPM for long periods of time.. around 3-4000 RPM...

 

not high revving, rapid RPM changing engines like a car

 

I'll be honest, I don't get this argument, since by that logic, avgas would be crap for in town driving, but once you get on the highway, all of a sudden it's great.

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I look at it this way: Gas is gas is gas. Plus, if there was such a big difference in the requirements for aircraft and auto engines, they wouldn't use LSxs, 13Bs, and subie engines in airplanes (or 87 octane for that matter).

All I can say is that I used the avgas and unleaded mix and had great results. I also used race gas and cut it with unleaded, that worked well too. I also used Tolulene and Xylene in the DIY octane booster mixes and had good luck there as well.

 

I am inclined to agree with you.

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Sorry I thought I posted what being ramp checked is. Most general aviation airports have an FSDO flight standards district office run by the FAA. What they do is cruise the airports and do random checks. They check airmans certificates, ask you questions about where you are going, check inside your aircraft. Basically what amounts to a traffic stop. The chance of being ramp checked is remote, but I thought you should know what goes on at an airport.

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