[Diy_efi] WI, methanol, and corrosion

[Greg Hermann]

At 1:39 PM 1/23/03, Axel Rietschin wrote:
>----- Original Message -----
From: "Marcell Gal" <cell at x-dsl.hu>
>To: <diy_efi at diy-efi.org>
>Sent: Thursday, January 23, 2003 4:12 AM
>Subject: Re: [Diy_efi] WI, methanol, and corrosion
>
>
>> > the combustion chamber. This excess water will not evaporate fully in
>> > the throttlebody because the intake charge is already at its dew
>> > point and the excess will remain in suspended liquid form.
>
>Even a little water evaporation (before it enters the cylinders) will
>displace _some_ oxygen and this is a bad thing.
>
>> This saturation issue (mentioned by several people) sounds
>> logical to me.
>> Does it mean that it does not make a big difference where we place
>> the water injector (but it must be after intercooler, of course).

You can even do it INSTEAD of the intercooler !!

What IAT are you getting after the IC ?? How much pressure drop across it ??

Fact is, the vapor pressure of water at the IAT you are getting after an IC
is _probably_ less than the pressure drop you are seeing _across_ the IC,
and you will quite likely have evaporated enough water to get enough
adiabatic cooling  effect to cool the air stream to that temp !!

Yes, the water vapor displaces some air/oxygen, but since the vapor
pressure of the water is likely less than or equal to the pressure drop you
would have had through the IC, there is no net loss, maybe even a net gain
!!

Greg
>
>Yep.
>
>> So why bother with lotsof water/methanol injectors when
>> a quite good setup can be achieved by having a
>> - central ("throttle body") water injector
>> - central ("throttle body") methanol injector
>> - sequential port gasoline injectors
>
>If you treat water as fuel, treat water like fuel :-)
>
>Besite that, methanol will increase the combustion temp. While it is true it
>resists knock more than gasoline, it is nowhere near as effective as
>suppressing the phenomenon as pure water alone.
>
>
>
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