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fleebut

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There is a way to fund it, help me build an engine. :) I have need of a crank kit for the really high compression engine, and one of the EFI systems I was talking about would be nice too. Anyone want to donate to the cause? The crank kit is about $1400 and the EFI system I want to try is right around $1300. That would net me a 13:1 467 ci engine. As it is the one I am doing this summer consists of the 455 that is in my 70 GTO getting some small chamber heads that will make around 11.3:1, not exactly super high, but more than pump gas will handle and I know how well that engine combination ran on race gas. The GTO needs lots of work, mostly to fix rust issues and electrical gremlins, plus it has been run pretty hard being my daily driver for almost 15 years, so the engine is going in a different car.

 

There is no way I would want a ready mixed tank of vapor in the car. Hindenburg in New jersey comes to mind but on a smaller scale. I am only planning to heat it just prior to its injection into the airstream, and the heated fuel rails Obermot has for cold starts could work quite well if they can run continuously and keep the fuel temp over 200F. I dont have those, and that is too much for a carb to handle since it is vented to outside air and that poses other issues along with only a 7psi fuel system, so it would only work very well with a higher pressure EFI system with around 60psi.

 

Im not so much talking about flame speeds when I say ethanol burns faster, flame speed is controlled/influenced by other things in an engine like AF ratio for instance. I am refering to how the individual droplets burn. A droplet can only burn the outside edges and the speed of the burning increases slightly as the drop gets smaller, less surface area to cover. The difference between gasoline and ethanol is that the droplets for ethanol burn in such a way that they are done burning almost as soon as the work is completed and the gasses have expanded as much as they are going to from the heat. Gasoline is still burning the droplet, usually because it is much larger than the ethanol drop, but also due to makeup of the fuel. That continued burning creates more waste heat since the work is done and the energy has to go somewhere, so it goes to waste heat and into the metal surfaces of the engine and then to the cooling jacket. When we make those droplets very small, more like a fog or vapor rather than the coarse spray of an injector, we get a more complete burn with less waste heat. It is just far easier to control with ethanol than it is with gasoline, due to the boiling points of each fuel and its components. Getting some of the gasoline components to vaporize takes over 400F whereas ethanol only needs 173F at sea level. In a high vacuum condition in an engine it will vaporize at a lower temperature, but you are limited on how much time you have to achieve full vaporization, so you need to preheat the fuel in the rail. I wonder how many slightly different ways I can say the same thing.. :)

 

Why dont we have more intake fires and explosions? Well an engine is drawing air in under vacuum, like syringe pulling fluid into it. When there is only one way for the air fuel mix to go, and no ignition source, it will be quite safe. If the airflow were to reverse for a moment, then you could have a problem, but that only happens when there is some sort of catastrophic failure in an engine. Even if the fire does start prior to the spark or ignition from compression, it is headed into the engine not out of it.

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