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Old 11-06-2009, 02:13 PM   #18 (permalink)
drew1d
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Join Date: Nov 2009
Location: Pawlng
Posts: 21

Push - '03 Honda Civic Si (Ep3)
90 day: 28.27 mpg (US)
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Quote:
Originally Posted by Christ View Post
You got some sources/references to back that up?

I'm sure there are lots of turbo guys and FI guys in general that would love to disagree with you, and set up complete injection systems on their engines for the express purpose of injecting water/methanol into their engines, making more power and efficiency as a result of doing so.
Disagree, if they want.

Let me see if I got this right, inside the combustion chamber is a mix of gasses, for simplistic terms will say Fuel vapor and 02. With the right ratio, all the 02 and fuel are burnt, the gasses heat up and expand and push the piston.

Adding water vapor does a few things. It's material that expands when heated as well, and if it takes some of the heat away from the cylinder as it isn't the agent that is combusting. This slight amount of vapor expanding in the cylinder is what's giving the power? I wouldn't say that the water vapor isn't really chemically changing anything. It doesn't really mix with gas or oil.

Water vapor also slows pre-detonation, like the fuel is a higher octane, so you'd also have to tune your car for it.

If you can figure out a good way to do that, then I guess you may see some higher mpg's if you dial it in just right.

The part where I would NEVER advise anyone to consciously put water into the engine is because of blowback gasses. As the cylinder fires in normal operation of the car, a small amount the expanding gas blows past the piston rings into the engine, causing pressure to build up. A PCV valve is used as a one way valve to relieve the pressure of the gasses, and vent them into the intake. Water vapor in the oil causes it to gunk up. Either having that valve stick open, or gunking up other parts of the engine. The worst thing I'd think you can do is have a turbo setup where the oil line cooling the turbo could get gunked up.

So higher mpg at the cost of engine parts? Not worth it. Imagine all the energy (probably electricity from burning oil) it takes to machine the parts the water would destroy? That's like the opposite of what I want.

If water in the gas really worked, then if I used 10oz of fuel in my chainsaw on a dry day, lets say it would idle for an hour. And on a foggy humid day, it would idle longer, no? Would you feel that's an accurate test?
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