Flow rates for nozzles

[Barry E. King]

> -----Greg's Original Message-----

> An alky rated injector should do it just fine. Dunno as I would
> want to use
> a standard petrol rated injector unit, though--but if that is what you
> have, what's to lose??? Worst they can do is plug up with corrosion and/or
> quit working, then you could replace them with Alky rated units.

I have several perfectly good injectors to play with.  Guess we'll see  ;)

> Filtering the water would, of course, be just as critical as
> filtering fuel
> is to injector life, tho. It would definitely require a different type of
> filter element to work properly with water, so pay attention!! I
> would also
> suggest using only reasonably "soft" water. But DO NOT try using regular
> "softened" water, as it is full of sodium chloride!! You would need RO
> treated or demineralized water if decent quality water is not readily
> available to you.

Of course.  The purer the better to start with and filter it properly after
that.

> I hear (HI BRUCE) that about 1/2 the mass flow of fuel is about the right
> water flow rate. I also SUSPECT that if you are getting GOOD
> atomization of
> the water, injecting it close to the intake valve, AND synchronizing the
> squirt of the water with the inhale (high air flow velocity in the intake
> port) that a water mass flow rate as high as 100 or 125% of the fuel mass
> flow rate could have positive influence on HP output, particularly if you
> go with a higher than usual static compression ratio.

I need to mess around with the atomization aspect to see what pressure will
do the trick.  I want to keep the pressure lower rather than higher just for
cost's sake but will implement whatever works.

As to where to place the injector, the ultimate would be a dual feed
injector where the water and fuel were either mixed prior to injection or
injected simultaneously.  The former wouldn't be much different than a
direct port nitrous setup.  The latter injectors do exist but I have never
seen one for sale.  They'd be too pricey anyway.  I'll be injecting either
immediately before the throttle plate or immediately after right into the
plenum.  Also I will only be injecting at 15 PSI or above so presumably
there will be enough airflow to minimize or eliminate puddling.

The amount of water you quote sounds quite high unless I am misinterpretting
your terms.  I was thinking more along the lines of 5-15% water by weight of
fuel.  The rate is adjustable based on MAP and linked to IDC.  This range
was based on two things:  a study I read once which had quanitified results
(I really wish I had access to that study now) and the fact that the ERL
system's largest nozzle is 200cc/min at specified pressure.  I am open to
new numbers however.  How did you arrive at your numbers?  I'm using 720cc
injectors and will be running up to 25 PSI or so with water/alcohol
injection.

<snip>

> From what Bruce says, it sounds as though a mechanical (engine
> driven) high
> pressure water pump would be a good idea both so as to shed electrical
> overhead and so as to improve efficiency. DSR (Memphis, Tenn.) makes gear
> type FUEL pumps which are entirely hard anodized AND polymer coated on all
> internals as well. These units oughtta live pumping CLEAN water, but $$$
> again!

Yeah, makes sense.  In my particular situation, however, mounting a
mechanical pump will be rather tricky and likely not worth the grief.  I am
pretty much resigned to using an electric pump.

I believe I have a decent controller alogrithm worked out which will not
require external sensors except for MAP.  Now to get around to implementing
it.


Regards,

Barry