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Originally Posted by geokoppmann
Has anyone considered that the 'volumetric energy' may just be the wrong scale to use when comparing 105 octane Ethanol 86 octane unleaded gasoline ? If the 33% less volumetric Btu's were an accurate indicator then the 12 Horsepower increase demonstrated by four Dyno runs on my '98 Ford F150 couldn't happen BUT, it did ! AND, the Torque increased 5.5 ft-lbs. I had "Dyno Edge" in Albuquerque, New Mexico run two 'before' [on 86 octane unleaded gasoline] and, four 'after' [100% E-85 - no unleaded gas in the tank] Dyno runs on my '98 Ford F-150 XLT 5spd auto. My full tank of E-85 (blended to 85 (+/- 2) % enabled the 98,xxx mile 4.2L V-6 SFI engine to produce 12.2 more HP and 5.5 ft-lbs of Torque.
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If you are purchasing fuel by volume, and burning it to convert energy, then volumetric energy content is the
exact right scale to use. You are simply purchasing less energy in your gallon. There is no magic here. I would be interested in another hypothesis of why the fuel economy is so good, but let's respect the basics of chemistry.
I don't see the significance of the 105 octane. Unless you have modified your truck engine to require that octane (higher compression ratio via changes in pistons or combustion chamber, etc) it is irrelevant. It is simply an indicator of resistance to knock. I assumed you didn't modify your engine, since you switched back and forth between the two fuels. If you did modify your engine it explains the results on regular pump gas.
I don't see your point about the connection between fewer BTUs per gallon and more hp. If it makes more hp, great. You just can't get more hp out of the same volume of fuel, you will need more of it. This is a mileage question, not a hp question. I wouldn't worry too much about 12 hp, that is within the accuracy range of most dynos. Was it a different day, different ambient temperature, different barometric pressure?
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SO, it would 'seem' that the old 'anti ethanol' saw of 33% loss of gas mileage just doesn't add up when E-85 enables an internal combustion engine to develop more power at the rear wheels where a Dynomometer can measure it.......
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I didn't say 33%, not sure where that came from. It is 26% for pure ethanol, so that will only be a 22% impact on E85. That is still all about mileage, not hp. Sure you can potentially develop more hp, you will just need more fuel to do so.
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A FFV conversion unit does adjust the pulse width of the signal to the injectors.
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It is logical IMO that it will need a different pulse width, so that it can put more fuel in to the engine. The fuel injector is injecting a certain volume, not a certain amount of energy. It will need 22% more to be precise. That is what I am asking about.
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Maybe, just maybe, E-85 is just a 'better' burning fuel.
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No arm wrestle here on the burning of E-85. I am not suggesting that it pollutes more, or even the same as unleaded. If we want to call that 'better burning' then great, no problem. I just don't see how 'better burning' translates into producing energy that wasn't there to start with.
Interesting discussion.
PS: It makes it easier to follow if you don't insert your comments in other's quotes. It makes it look like they are the previous poster's comments. Just a suggestion.