[Diy_efi] higher pressure pumps for water injection

[Eric Fahlgren]

> "Porter, Bill" wrote:
> 
> Are these ratios by volume or my mass?

Mass ratio.

>  Sorry, But who is Ricardo and what is the title of his book?  Could someone email me (pdf or other) the pertinent pages on water injection?

Sir Harry Ricardo, The Internal Combustion Engine.  I've never seen it in PDF, it would probably
be huge, as the book is about 430 pages.

>  It is obvious that there is a lot more engineering (always is) to design a water injection system then to just cobble one together and make it spit water.

Yes, although that's not a bad place to start. :)

>  Are there any other links or resources that would help the DIY'er in me cobble together an engineered system?

Myriad NACA reports from the Ricardo's era are an veritable goldmine of
information.  As I alluded to a few minutes ago, it is hard to pick out
the nuggets that are shaped the way you like, there are just so many of
them.  Start off with Report 756, which Chris referenced:

http://naca.larc.nasa.gov/reports/1943/naca-report-756/naca-report-756.pdf

Check these out, too.

http://naca.larc.nasa.gov/reports/1922/naca-tn-93/naca-tn-93.pdf
http://naca.larc.nasa.gov/reports/1945/naca-wr-e-198/naca-wr-e-198.pdf

Search the archives and you'll find a couple more lists.

> Does anyone have or seen a "table" that explains the tuning aspect of water injection i.e. at what RPM, boost level, VE to remove X amount of timing?   I guess this would all be model specific to your engine a mods.

Never seen a table, never heard any rules of thumb for starting point,
I just plan on experimenting and seeing what happens.

> c) should mix with alcohol 50/50 so it acts to inhibit freezing and improve latent heat characteristics

Specific heat of pure water is far superior to h2o/ch3oh, reference
http://intenz.gotdns.com/~eric/cars/turbo/glossary/water_injection.html

> How big a deal is droplet formation size and uniformity?

Size is quite important, and contrary to all those Viagra commercials,
smaller is better.  Reference recent discussions on atomization vs
vaporization.

> What about dispersion within the manifold on say a supercharged Bonneville with a roots style blower and little room for mixing?  How about on an 91 EFI Mustang with twin turbos? Do you need to a use a NOS style fogger setup on to achieve
> dispersion or can you get away with a single nozzle.

You certainly want to distribute water as evenly you do fuel.  Pumping
it in before a roots blower should chop up the particles quite nicely.
Pouring it in before a turbo fan will also atomize the water along with
the compressor blades, so is often discouraged.  To see the various
effects of WI placement, which can be interesting, try out some configurations
with this:

http://intenz.gotdns.com/~eric/cars/turbo/glossary/turbo_calc.html

(WARNING: The WI modeling assumes 100% vaporization, so only "inject"
the quantity that you are guessing will actually vaporize.  How much
is that?  I have no idea, maybe 5-10% of total injected water?  Beware
that it assumes the water vapor has zero partial pressure, too, and
consumes no volume in the intake wrt HP calculations.)

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