Water injection (was: Re: fuel cooling intake air)

[Bruce Plecan]

> Said differently, everything you'd gain from a lower temperature would be
> lost because of oxygen displacement. Denser, yes, but that much diluted
with
> an inert substance.

Just one little problem, it works.
One of the toys I work on is a 436 CID engine running 60 PSI of boost, we
blow a gal of water thru it in about 15 secs..   Got some time in getting it
right, and fun watching others that haven't, figured water injection out.

> What you really want to obtain (and the only thing you get) from WI is
less
> detonation. This could allows more boost pressure and/or more spark
advance.
> I believe it's better to inject late so water enters the cylinders in
liquid
> form, and take very little space. You get in-cylinder cooling as expected
> and maybe also some extra pressure from water evaporation.

Less detonation, oh good, that's what a deisel runs on (compression
ignition).  My above example is a diesel so according to you it should run
poorer, oh OK.

> If you are concerned about the charge density, you can also consider to
use
> a more efficient intercooler and/or spray water on the outside of it. This
> will give you a cooler, denser charge, still 100% made of air.

Spray water thur the intercooler, onto the ground and then drive over it,
that really don't sound to smart.

> >> I've heard that the serious Rally guys inject before the intercooler
when
> using water injection.
> I've at least one counter example: the Ford Escort Cosworth World Rally
Car
> has both WI and an intercooler spray system, and water is injected after
the
> IC.

I can name examples of all kinds of stuff.  The key is execution.

> Just my $0.02
> Axel
> PS: About spraying FUEL before the IC, I hope you'll never have any
> backfire, because the mixture in most of the induction system will be
REALLY
> flammable, hot and compressed :)

If I have a backfire at WOT, there is a serious problem, and the worst part
is the cause of the backfire.  You making no disticntion about quanities,
and just using a worst case scenerio.  Fine.
Grumpy



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