The Ford Barn - View Single Post - E-85 ???

Old182 · 12-31-2011, 06:14 PM

Ethanol certainly has its downsides (not the least of which is political), but as mentioned earlier it also has a few upsides. From a purely performance standpoint, because ethanol contains 34.7% wt. oxygen, it "chemically leans" the fuel-air mixture and E85 could be expected to reduce range by almost 30% except ethanol has a high latent heat of vaporization and will increase the density of the incoming air (methnaol is higher and is one reason it's used in race engines). The denser air will allow more power to be made at a given manifold pressure (throttle position) and helps to offset the deficit in Btus, albeit not a lot. It will swell elastomers particularly in a high aromatic gasoline, it is miscible in water and it will clean out fuel systems - bummer. It's high octane number doesn't do much for Model Aers (remember our engines can run on kerosene) and water/alcohol separation may be less of an issue with our cars than modern cars; there are additives that prevent or reduce phase separation. The neat thing about Model As is that you can turn the GAV to richen the mixture significantly, perhaps allowing enough additional fuel so that re-jetting is unnecessary for E85. Using stoichiometric air/fuel ratios of 14.6:1 for all-hydrocarbon gasoline and 9.0:1 for E100, E85 would be about 9.8:1, or about 33% richer than "normal". If you prefer to drill jets, I believe it's the area of the jet hole that will need to be increased ~33% to get you started (old Holley advice). Good luck! Oh, and a very Happy and Healthy New Year to all!!

12-31-2011, 06:14 PM	#18
Old182 Senior Member Join Date: May 2010 Location: Newburgh, NY Posts: 222	Re: E-85 ??? Ethanol certainly has its downsides (not the least of which is political), but as mentioned earlier it also has a few upsides. From a purely performance standpoint, because ethanol contains 34.7% wt. oxygen, it "chemically leans" the fuel-air mixture and E85 could be expected to reduce range by almost 30% except ethanol has a high latent heat of vaporization and will increase the density of the incoming air (methnaol is higher and is one reason it's used in race engines). The denser air will allow more power to be made at a given manifold pressure (throttle position) and helps to offset the deficit in Btus, albeit not a lot. It will swell elastomers particularly in a high aromatic gasoline, it is miscible in water and it will clean out fuel systems - bummer. It's high octane number doesn't do much for Model Aers (remember our engines can run on kerosene) and water/alcohol separation may be less of an issue with our cars than modern cars; there are additives that prevent or reduce phase separation. The neat thing about Model As is that you can turn the GAV to richen the mixture significantly, perhaps allowing enough additional fuel so that re-jetting is unnecessary for E85. Using stoichiometric air/fuel ratios of 14.6:1 for all-hydrocarbon gasoline and 9.0:1 for E100, E85 would be about 9.8:1, or about 33% richer than "normal". If you prefer to drill jets, I believe it's the area of the jet hole that will need to be increased ~33% to get you started (old Holley advice). Good luck! Oh, and a very Happy and Healthy New Year to all!!