grpark20 Posted March 6, 2007 Report Share Posted March 6, 2007 Before I start, I did the search and still couldn't anyswer my question. I read all the debates and heard both sides about the lead deposits, lubrication, and cost difference so......Has anyone ever actually had a problem running AV GAS? I've read what it can or can not cause but has anyone really ever had a problem? Any info will be great. Also, I'm not the octane expert so, will 170psi and +4 timing be ok on staright 100LL AV GAS? Or would you run higher octane? PLEASE DON'T RIP ME A NEW ONE....I'M STILL A ROOKIE!!! :biggrin: Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 6, 2007 Report Share Posted March 6, 2007 i personally run normal unleaded race gas.... but i know of a few guys that run av gas... they have no problems... just run good ratios and you shoul dbe fine... 100 oct is cutting it close.. if you got a place to buy some 110 youd be safer... Quote Link to comment Share on other sites More sharing options...
mpbanshee Posted March 6, 2007 Report Share Posted March 6, 2007 I have 175 psi per cylinder, and vary between +4 and +7 timing advance. I have been running 100LL with castor 927 synthetic at 40:1 for years now and have never had a problem. No carbon buildup on ports, head, or pistons, no detonation problems. Runs great and smells good too! Quote Link to comment Share on other sites More sharing options...
grpark20 Posted March 6, 2007 Author Report Share Posted March 6, 2007 I like what I'm hearing so far!! If the cost difference isn't that much then I'm just going to run race fuel if I can find it in WA. The AV gas is about $4.50 a gallon at the municipal airport. I hate to find out the price of the race gas!!! Quote Link to comment Share on other sites More sharing options...
06BaNsHeE Posted March 6, 2007 Report Share Posted March 6, 2007 Look around in any small airport near you.I pay 3.40 for a gallon.But I mix it with a little pump gas.NBope Ive never had a problem with avgas Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 7, 2007 Report Share Posted March 7, 2007 not sure for Wa but race ga in san diego is 6 buck a gallon Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 7, 2007 Report Share Posted March 7, 2007 Before I start, I did the search and still couldn't anyswer my question. I read all the debates and heard both sides about the lead deposits, lubrication, and cost difference so......Has anyone ever actually had a problem running AV GAS? I've read what it can or can not cause but has anyone really ever had a problem? Any info will be great. Also, I'm not the octane expert so, will 170psi and +4 timing be ok on staright 100LL AV GAS? Or would you run higher octane? PLEASE DON'T RIP ME A NEW ONE....I'M STILL A ROOKIE!!! :biggrin: Properly used, I don't think anyone will have a problem running AV gas. You may have read during your search for info on this site that I am one of the big opponents for running AVgas. When you read what I have written on the subject you need to understand that I basically knit pick over very small details inorder to state that race gas in a more appropriate fuel for a Banshee. :thumbsup: Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted March 7, 2007 Report Share Posted March 7, 2007 According to Dyno Dave at ILR Performance, the benefits to AV gas dont out weight the cost when compared to leaded high octane race gas. I cant remeber what he said the av gas would do, but he himself runs high octane race gas and he makes his own ethanol from his apple trees. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 7, 2007 Report Share Posted March 7, 2007 he makes his own ethanol from his apple trees. He sounds like my kind of guy. :thumbsup: Quote Link to comment Share on other sites More sharing options...
bluev8s10blazer Posted March 7, 2007 Report Share Posted March 7, 2007 I like what I'm hearing so far!! If the cost difference isn't that much then I'm just going to run race fuel if I can find it in WA. The AV gas is about $4.50 a gallon at the municipal airport. I hate to find out the price of the race gas!!! what part of washington are you from?? Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 7, 2007 Report Share Posted March 7, 2007 he makes his own ethanol from his apple trees. in my neck of the woods we like to call that moonshine Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 7, 2007 Report Share Posted March 7, 2007 what part of washington are you from?? Yeah, let us know. I grew up there and I am pretty sure I can come up with some place that sells race gas near you. :thumbsup: Quote Link to comment Share on other sites More sharing options...
Blue Duece Posted March 7, 2007 Report Share Posted March 7, 2007 and he makes his own ethanol from his apple trees. i know a guy who can suck his own dick...........but if his shee has a 170 psi per jug or better he needs to run 104-108 race fuel Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 7, 2007 Report Share Posted March 7, 2007 i know a guy who can suck his own dick........... How does a person come to have this information about another person? Quote Link to comment Share on other sites More sharing options...
blowit Posted March 7, 2007 Report Share Posted March 7, 2007 Yeah, let us know. I grew up there and I am pretty sure I can come up with some place that sells race gas near you. :thumbsup: AV fuel is absolutely fine to run and will not hurt an engine at all. Its higher octane is is mostly achieved by the introduction of lead in the fuel. Lead retards detonation by absorbing shock waves at at molecular level and, as being a non-ferrous metal, absorbs heat readily. This means it will actually extract heat from the combustion cycle and carry it out the pipe. Lead also acts as a lubricant to further reduce the chance of detonation. Anytime you purchase a commercial fuel that must meet so many criteria and EPA guidelines, it has to have special additives. These additives lengthen shelf life, reduce fuel gel, minimize deposits, and so on. These additives can be as much as 15% of a given fuel by volume. These fillers do not contribute to the combustion cycle thus acting as "inert" fillers in the cycle. No good for HP but when your flying, fuel gel can be a much bigger concern. Racing fuels by design are refined with different guidelines and additives are drastically reduced thus allowing more burnable fuel in the combustion cycle. They generally have more lead as well to also raise the octane number as well. In short, race fuels are far superior to AV fuels, BUT, please keep in mind that as the octane of a fuel is raise, so is it's rate of combustion. This means DO NOT buy more octane than you need. Please use octane as a " safety" number as this is only the rating of a fuels resistance to pre-ignition. I think someone was asking about 175psi static with 4 degrees advanced. That setup at sea level might indicate a 21cc chamber with a stock port height and a corrected comp ratio of 6.8:1. That ratio is within the safe limits of standard pump fuel. Will someone make more power with AV fuel with that setup? NOPE. With race fuel? only if the ignition is further advanced to compensate for the slower burn rate. You have to "get the party started" a little earlier with race fuels. The nice thing with race fuels in thumpers is the slower burn rate really helps by applying for to the piston through most of the stroke, not just 20 degrees like pump fuels. Unfortunately, two-strokes do not have a long enough blow down time to take full advantage of this. In short, you should only use AV fuel over pump to supress detonation, not the make power. The big power gain is in Alky because it has extra O2 bonded in the fuels molecules thus acting like a small chemical supercharger. Methyl fuels will contain almost 50% O2 by molecular composition. Quote Link to comment Share on other sites More sharing options...
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