100 LL
- Thread starter phoonrt
- Start date
xcaliber
New member
I belive it is to "dry" by itself, I got some buddies that run it, mixed with oil, something like 1/2 pint to 5 gallons of airplane fuel, but I'm not sure on the mixture,
you only need enough octane to stop knock, any extra is useless and will not create more power, although more octane will allow for a little higher timing with will make more power,,,, :drinking: now I'm confused!
you only need enough octane to stop knock, any extra is useless and will not create more power, although more octane will allow for a little higher timing with will make more power,,,, :drinking: now I'm confused!
TechWeasel
New member
100LL avgas is "low lead" only in comparison to other aviation fuels. It's got more sensor and cat killing lead than the worst 1960's premium...
20psiGMC
Member
This is a topic that has interested me for a while now, since as Waller mentioned, 100LL is cheap. I was running it in dirt bikes for $2/gallon 15 years ago. A call to the local airport reveals it’s now $2.50/gallon, a whopping 25% increase in 15 years; whereas pump gas has more than doubled.
According to the one spec sheet I have, 100LL has 2 grams of tetraethyl lead per gallon. This puts it at about ½ (or less) the lead content of most leaded racing fuels, which seem to average between 4 and 6 grams of lead per gallon. Opinions are varied as to how much lead 02 sensors/cats will endure and for how long….
I have also heard the concern of it being a “dry” fuel. Airplanes are subject to mandatory overhauls at certain intervals, so compromises could be made in fuel formulation in regards to wear additives. I’ve asked some of the local stock car guys about that in the past, and one did tell me he quit using it because he saw increased piston crown wear. However, he did also say he was at the limit (octane wise) of what the AV gas would support, so perhaps the effects of detonation was what he was seeing.
Third point is the density of the fuel. AV gas is substantially lighter than automotive fuel (.3# to .4#’s/gal.) so running it with chips calibrated for auto fuel might be a problem. In this same vein, one other tech paper I have states the lesser weight is due to formulations that omit the “heavy end” of the gas molecule. The end result is a fuel that is lighter (good for aircraft) burns cooler (good for aircraft and us) but lacks the overall energy of auto fuel (not bad for small engine aircraft, bad for us). They advocate a 50/50 mix of auto/AV to capture the octane of the AV gas and still have some “heavy end” molecules.
Empirical data is far better than theory and speculation, so for you guys that have done it;
1) Are you mixing it or running it straight?
2) What fuel management are you using?
3) Does it make good power?
4) Have you had the opportunity to run it for a while, then inspect the top end?
Just trying to put this issue to bed, and maybe come up with a lower cost alternative for some applications.
According to the one spec sheet I have, 100LL has 2 grams of tetraethyl lead per gallon. This puts it at about ½ (or less) the lead content of most leaded racing fuels, which seem to average between 4 and 6 grams of lead per gallon. Opinions are varied as to how much lead 02 sensors/cats will endure and for how long….
I have also heard the concern of it being a “dry” fuel. Airplanes are subject to mandatory overhauls at certain intervals, so compromises could be made in fuel formulation in regards to wear additives. I’ve asked some of the local stock car guys about that in the past, and one did tell me he quit using it because he saw increased piston crown wear. However, he did also say he was at the limit (octane wise) of what the AV gas would support, so perhaps the effects of detonation was what he was seeing.
Third point is the density of the fuel. AV gas is substantially lighter than automotive fuel (.3# to .4#’s/gal.) so running it with chips calibrated for auto fuel might be a problem. In this same vein, one other tech paper I have states the lesser weight is due to formulations that omit the “heavy end” of the gas molecule. The end result is a fuel that is lighter (good for aircraft) burns cooler (good for aircraft and us) but lacks the overall energy of auto fuel (not bad for small engine aircraft, bad for us). They advocate a 50/50 mix of auto/AV to capture the octane of the AV gas and still have some “heavy end” molecules.
Empirical data is far better than theory and speculation, so for you guys that have done it;
1) Are you mixing it or running it straight?
2) What fuel management are you using?
3) Does it make good power?
4) Have you had the opportunity to run it for a while, then inspect the top end?
Just trying to put this issue to bed, and maybe come up with a lower cost alternative for some applications.
Twins
Donating Member
I've run 100's of gallons of 100 ll thru my GN. Last summer I put one tank of pump fuel in it. I don't see any difference in how fast it kills the non-heated 02's but I've never run it in the Ty.
This topic gets a heated debate going every couple of months on the turbo buick board, go there and so a search for av fuel.
From what I understand it's 108 octane if measured by auto fuel standards.
I guess the bottom line is occasional trip to the track or weekend street work it would'nt hurt, but I can't imagine using it in a driver. 02's are too much $, and if you still have a cat it'll kill that to.
Smells cool when it burns just like race fuel but good luck getting a street race if the poor sucker next to you smells it. I've had guys back out telling me pump fuel only. WTF is that?
This topic gets a heated debate going every couple of months on the turbo buick board, go there and so a search for av fuel.
From what I understand it's 108 octane if measured by auto fuel standards.
I guess the bottom line is occasional trip to the track or weekend street work it would'nt hurt, but I can't imagine using it in a driver. 02's are too much $, and if you still have a cat it'll kill that to.
Smells cool when it burns just like race fuel but good luck getting a street race if the poor sucker next to you smells it. I've had guys back out telling me pump fuel only. WTF is that?
Deanzsyclone
New member
Re: 100 LL
That is why I use this in with my 91 octan. I seem to get alot of comments about my exhuast smelling like race gas, guess that's why. If you order the 6 gallons and do the math, then you will see it's only about 10 or 15 cents more a gallon and what you end up with is a much higher octane rating. Just my two cents.
20psiGMC said:According to the one spec sheet I have, 100LL has 2 grams of tetraethyl lead per gallon. This puts it at about ½ (or less) the lead content of most leaded racing fuels, which seem to average between 4 and 6 grams of lead per gallon. Opinions are varied as to how much lead 02 sensors/cats will endure and for how long….
.
That is why I use this in with my 91 octan. I seem to get alot of comments about my exhuast smelling like race gas, guess that's why. If you order the 6 gallons and do the math, then you will see it's only about 10 or 15 cents more a gallon and what you end up with is a much higher octane rating. Just my two cents.
It's just a six
Super Member
Re: 100 LL
Thats why I recommend:::
http://www.speedwaymotors.com/p/1656,58_Fuel-Fragrance-Additive.html?itemNo=fuel additive
Deanzsyclone said:
Thats why I recommend:::
http://www.speedwaymotors.com/p/1656,58_Fuel-Fragrance-Additive.html?itemNo=fuel additive
poorboy93
Veteran S10 Owner
Re: 100 LL
My :2cents: I wouldn't personally run it. Just thought I'd mention, I bought Ty #0157 8 years ago from a "well Ty educated" aviation pilot who managed/flew 7 jets. I recall rumors from a friend who worked by his hanger of running Ammoco aviation fuel every now and then in the Ty, but yet unconfirmed. The guy was by no meams "Ty stupid", and the truck runs great untill this day if he did.
My :2cents: I wouldn't personally run it. Just thought I'd mention, I bought Ty #0157 8 years ago from a "well Ty educated" aviation pilot who managed/flew 7 jets. I recall rumors from a friend who worked by his hanger of running Ammoco aviation fuel every now and then in the Ty, but yet unconfirmed. The guy was by no meams "Ty stupid", and the truck runs great untill this day if he did.
Deanzsyclone
New member
Re: 100 LL
i use it sparingley so no issues with 02. Sensor. But I should remove it just to be safe.20psiGMC said: