Profilact Posted March 27, 2009 Report Share Posted March 27, 2009 (edited) samething i was thinking... Whats crazy about it? (sorry about the triple post) Edited March 27, 2009 by Profilact Quote Link to comment Share on other sites More sharing options...
sandman81 Posted March 27, 2009 Report Share Posted March 27, 2009 Whats crazy about it? That I get away with it? I dont understand... That one thing that's crazy, and your comparing two different fuels with two different octane numbers. Comparing these two is like comparing apples and oranges. If you compared something like Motorsport 109 that has a 101 mon then I could see a good comparison just because the octane number are almost the same. C-12 has a 108 motor octane number and avgas has 100 mon. If your running with avgas and not having problems then C-12 would be pointless that would mean that any good fuel that has a 100 mon would work just fine. If your engine or anybody engine need a minimum of 108 mon then avgas would not cut it, no if's, and's, or, but's, about it. Quote Link to comment Share on other sites More sharing options...
Profilact Posted March 27, 2009 Report Share Posted March 27, 2009 (edited) I see what you are saying. Not trying to be an ass, but if you NEEDED an higher octane fuel, and C-12 and AV gas cost the same amount, what would you run? Would you rather run a fuel that is formulated for racing, or a fuel that is formulated for aircraft. As you can see from my sig, if I had a lot more dough, I wouldn't have blue nerfbars on a yellow Banshee. Thats why I say "strictly" for the cost. It has ZERO to do with what I NEED to run, but does at the same time. I KNEW I would need at least 100 octane with the compression and timing I wanted to run. And it could be lower, but I KNOW I am not safe on pump gas. I may be taking this the wrong way, which is often done when reading "text", but it seems that you and the other guy that posted about this are insulting my intelligence. I hope I am wrong. Edited March 27, 2009 by Profilact Quote Link to comment Share on other sites More sharing options...
regalrocket Posted March 27, 2009 Report Share Posted March 27, 2009 As a 10 year aviation mechanic and FAA licensed inspector, commercial pilot (large piston twins as well = high altitude) and flight instructor, I will try to give some facts as I know them. 1. 100LL has ALOT of lead, something on the order of 5 times what normal automotive leaded gasoline had back when it was at the pumps. 2, This lead WILL leave deposits on piston tops and exhaust components (which accounts for it being "dirty" fuel) Lead is a white looking substance when it is deposited, but with the addition of our two stroke oil staining it with carbon, it looks like heavy oil deposits. 3. It is VERY HIGH quality fuel. A petrol engineer that I know said it is much much better than normal pump gasoline. It has very high quality additives, that will not break down. Aviation gasoline can last many years with zero breakdown issues. Its high quality is the reason that it smells totally different, and does not stink like autofuel. 4. It has a lower vapor pressure for high altitude use (similar to winter autofuels). USELESS AIRPLANE FACTS : Piston powered aircraft can rarely go over 14,000 feet unless supercharged, and if they are supercharged, normally 25,000 feet is the absolute altitude that can be obtained. Most 100ll aircraft never get above 8,000 feet. 5. The fuel is slower burning than normal gasoline. This is a good property for slower turning aircraft engines that never go above 3,000 rpm (except for the newer rotax engines). Automotive race gas is also a slower burning fuel, hence the high octane ratings. Take it for what its worth. My personal opinion is that I would run race gas in a banshee just because of the lead deposit issue. Many aircraft were originally designed for 80 octane avgas, but with that no longer in production, we have to use 100ll. It makes a big mess of the exhaust and piston domes, leaving deposits that are heavy. We sometimes mix normal auto fuel to achieve a higher compustion temprature to help burn these deposits off, or keep them from developing. Avgas would be a great fuel for a drag machine or something that doesn't get alot of miles on it. But for a trail machine, I will keep burning autofuel. I wish avgas was better, as it doesn't stink 1/4 as bad as autofuel, but there is alot of lead in that stuff. Thats my 2 cents. Quote Link to comment Share on other sites More sharing options...
sandman81 Posted March 27, 2009 Report Share Posted March 27, 2009 (edited) I see what you are saying. Not trying to be an ass, but if you NEEDED an higher octane fuel, and C-12 and AV gas cost the same amount, what would you run? As you can see from my sig, if I had a lot more dough, Not being a ass, Deffentaly the C-12. Imo, you should always run a fuel that has a higher octane number then needed. Ex: If you need 100, should run atleast 102, so you'll have some leeway. I know times are tough, belive me I know. If you go cheap on your fuel on a worked up engine and something goes BOOM you'll be kicking yourself in the ass. What i would do is look into running another brand of race fuel that is cheaper. I don't know what C-12 cost is in your neck of the woods but vp 110, same brand and similer to C-12, is around $10/gallon. So I run Torco 110 (7.50/gallon) or Trick 110 (8/gallon), thats because if one shop in town don't have one i go to another shop and get the other. Like you said no problem with the avgas, then i guees fuck it stick to what work. Edited March 27, 2009 by sandman81 Quote Link to comment Share on other sites More sharing options...
Profilact Posted March 27, 2009 Report Share Posted March 27, 2009 Ok cool. Yeah around here C-12 goes for 70 bucks a five gallon drum so when you do the math it comes out to 14 bucks a gallon. I like to ride at least 2 days out of the weekend (4 10's) so it adds up. As a matter of fact, I just sold my jet ski and and FINALLY going to buy some a-arms and shocks. I cant wait! Quote Link to comment Share on other sites More sharing options...
poorboystoys Posted March 27, 2009 Author Report Share Posted March 27, 2009 As a 10 year aviation mechanic and FAA licensed inspector, commercial pilot (large piston twins as well = high altitude) and flight instructor, I will try to give some facts as I know them. 1. 100LL has ALOT of lead, something on the order of 5 times what normal automotive leaded gasoline had back when it was at the pumps. 2, This lead WILL leave deposits on piston tops and exhaust components (which accounts for it being "dirty" fuel) Lead is a white looking substance when it is deposited, but with the addition of our two stroke oil staining it with carbon, it looks like heavy oil deposits. 3. It is VERY HIGH quality fuel. A petrol engineer that I know said it is much much better than normal pump gasoline. It has very high quality additives, that will not break down. Aviation gasoline can last many years with zero breakdown issues. Its high quality is the reason that it smells totally different, and does not stink like autofuel. 4. It has a lower vapor pressure for high altitude use (similar to winter autofuels). USELESS AIRPLANE FACTS : Piston powered aircraft can rarely go over 14,000 feet unless supercharged, and if they are supercharged, normally 25,000 feet is the absolute altitude that can be obtained. Most 100ll aircraft never get above 8,000 feet. 5. The fuel is slower burning than normal gasoline. This is a good property for slower turning aircraft engines that never go above 3,000 rpm (except for the newer rotax engines). Automotive race gas is also a slower burning fuel, hence the high octane ratings. Take it for what its worth. My personal opinion is that I would run race gas in a banshee just because of the lead deposit issue. Many aircraft were originally designed for 80 octane avgas, but with that no longer in production, we have to use 100ll. It makes a big mess of the exhaust and piston domes, leaving deposits that are heavy. We sometimes mix normal auto fuel to achieve a higher compustion temprature to help burn these deposits off, or keep them from developing. Avgas would be a great fuel for a drag machine or something that doesn't get alot of miles on it. But for a trail machine, I will keep burning autofuel. I wish avgas was better, as it doesn't stink 1/4 as bad as autofuel, but there is alot of lead in that stuff. Thats my 2 cents. thanks this is the answer i was looking for :thumbsup: Quote Link to comment Share on other sites More sharing options...
deckheight Posted March 28, 2009 Report Share Posted March 28, 2009 Pretty accurate IMHO except for the gunking stuff up part. AV does leave lead ash deposits. IMP experience over the last 30 years or so using the stuff off and on... The deposits do not build up in a 2-stroke. Don't know about 4-strokes??? The FAA doesn't seem to have much of a sense of humor when air planes start falling out of the sky though. In fact, I am running AV again because of it's availability. Or should I say lack of availability of something else. I have had the top end opened up a couple time recently and noticed nothing unusual I would attribute to the fuel. At any rate I am happy with it... Again thanks this is the answer i was looking for :thumbsup: Quote Link to comment Share on other sites More sharing options...
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