Toyota Supra twin turbo and water injection.

[Greg Hermann]

>At 11:59 AM 4/3/99 -0700, you wrote:
>
>>
>>2. A small amount of water (maybe 10% of fuel mass flow rate) after the
>>intercooler will yield some evaporative cooling of the charge air, and give
>>you a net gain of maybe 1% after correcting for the amount of oxygen which
>>is displaced by the resulting water vapor.
>
>How about substituting Methanol or Ethanol for the water... higher heat of
>vaporization (cools better as it evaporates) Plus it supplies additional
>fuel to the engine *AND* increases effective octane of the cylinder
>charge... Pretty good gains to be seen here if it's metered right!

To save going to look it up--ethanol and methanol each have heats of
vaporization far LOWER than water--no more than half. But--yes, they do
have higher vapor pressures at lower temps, which helps the case for using
them some.

Both of these alchohols are pretty high octane, but NEITHER one of them is
an "anti-detonant" in the sense that water is.

Additional fuel to the engine does not affect power--additional oxygen into
the engine is what makes more power, by means of burning more fuel,
possible.

Methanol WILL release more heat of combustion per pound of oxygen breathed
into an engine than gasoline will,  ethanol will NOT!!

The biggest trick to this stuff is to avoid going above the saturation
point with respect to any particular liquid/vapor mixture at TDC. If you
do, the latent heat required to evaporate any remaining liquid will sop up
heat of combustion, and rob you of efficiency and power.

Engines running on straight methanol  are this way--there is not enough
heat available during the compression stroke to evaporate all of the fuel,
so there is still liquid fuel in the chamber when the spark goes off. This
is why alky (methanol) fueled engines are hard to light, and also why their
thermal efficiency is rather poor, and why they need a lot of spark advance
(despite the fact that they make a lot of power, the first part of their
fuel burn goes into evaporating the rest of their fuel, not into pushing on
their pistons!!!)

Regards, Greg
>
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>           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
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