Water injection.

[Mike (Perth, Western Australia)]

At 07:54 PM 18/3/2000 +0800, Bernd Felsche <bernie at perth.dialix.com.au> wrote:
>Mike writes:
>
>My main concern with pumping water directly is with it running dry.

I was going to put one of the pumps at the bottom so it always has fluid
and also on a slight angle on the impeller exit side so any minor bubble
from anywhere would tend to ride up out and up the pipe away from pump
a simple washining machine level sense switch  in series with pump...

>That's why I like the idea of using an air jet - provides excellent
>atomisation at fairly low pressure - but you need the flow (or vice
>versa). What convinced me was watching a spray-painter: They don't
>pressurise the paint cans.

Interesting, there's a spray painter spares part dealer in Osb park,
I'll drop by during the week and have a closer look. What I wish
to do is flow water around and near the nozzle at low temp in readiness
for a spray - that way I have consistency - fuel rail fashion, I'm not
sure how it would work feeding fluid/air in at boosts of 15psi or so,
perhaps a small booster water pump to assure minimum water pressure into
the nozzle - with higher pressure feed from a PET bottle, 2L air reservoir,
kept at a minimum 50psi or so by an air pump.

Any thing I do ont his I want to achieve consistency in temp and flow.

>Then there's the stuff that's in the water - loads of minerals. The
>8 litres of water I put in my windshield washer reservoir is enough
>to discolour the inline filter I put in. (The filter is virtually
>useless - it didn't cost much to try - but I wouldn't recommend it.)

Yeah true, making your own distilled water though is dead easy, now
that we have summer finishing, rain water makes a good start for the
still ;)

>Perth water: You can make a meal of it!

Not as bad as Adelaide, when I was over there,  boiling in a saucepan
produced a vile froth on top - Yuck - I hear melbourne's water is starting
to go the same way - I think Perth (on average) has less dissolved minerals
then most other capitals (cept hobart/bris perhaps), I think its actually
close
to WHO limits though !

>>These are centrifugal and will do 15psi easily - though they are very
>>temperamental if there's the slightest amount of air in the line.
>
>They tend to be.

Yeah the funny thing is its hysteresis traps it, ie. With minor positioning
change it can be reduced otherwise its a bad trap.

>>The impeller is also a little temperamental if there's any dirt, it causes
>>the impeller to shaft to strip - but reglung it is easy.
>
>What is easy?

3 screws undo the impeller cover, clean up impeller centre with scalpel,
dab a little araldite to set o/night, screw back. These things are made
with nylon keyway in the nylon impeller and pressfit onto offset shaft,
dead cheap but prone to strip if the impeller pulls in any dirt.

I'd got a couple (one spare) and took the first failed one back on
the 90 day warranty - and accepted, the second one however looks too
dirty and used so they'd probably object if it failed now...

I also use one for the laundry - waste water to outside toilet cistern,
thats the one that failed due to lint and sand etc, But I've glued it
and its ok now.

>>With a good filter, correct positioning etc, it should be possible to
>>operate them reliably - thats what I will be trying shortly,
>
>It'll be interesting to see how well (and long) it works.

The one I've used for the cooling system pressuriser hasn't failed as yet,
and thats been there around six weeks - before that I had a "Whale", the
seals on that were terrible. I cycle the pump about twice a day to 15psi
and toggle a solenoid to purge air from the head, here's a pic:-

http://www.wantree.com.au/~erazmus/Twin_tyre_vehicle/Purge_Gauge_Switches.jpg

>  Make sure
>your water tank has anti-surge baffles and put in a level sensor
>that triggers well above the suction line. Not sure how you'll go
>with sucking water through an inline filter - I suppose if you
>ensure a static head it should be OK.

Yep, have a couple of those Hoover sensors - work fine, but I won't be
sucking water - the bottom of the botle has a feed to pump and filler from
top so it will always have water...

>Pretty sure I can get one through the store down in Rockingham.

Ah right, I used to live down there, 14 Cygnus St, next to underpass
about 1972, there's now some nice new restaurants at the beach where the
old pier is - great mussles :) Pity the old loco is gone from the park
though - my kids would have loved that - the beach is still clean though :)

>Well I do find that there is some preheating necessary for the fuel.
>After removing the intake silencer on my (and getting a very nice
>transient throttle response improvement as well as a drop in fuel
>consumption), I found that the engine would sometimes falter on
>sudden throttle openings during cold nights and mornings; when it's
>5C or less.
>
>The reason for that was that the pre-heat flapper used to close
>against the outlet of the intake silencer - which was no longer
>present. So the engine got a healthy dose of very cold air.
>
>The pre-heat flapper is thermostatically-controlled, with vacuum
>servo to move the pre-heat as required. The flap is supposed to be
>fully closed at 25C, Fully open below 20C. That's also to prevent
>icing of the throttle valve, btw.
>
>My fix was to put in a new flap across the opening left by the
>removal of the silencer, and link it back to the pre-heat flap so
>that it would shut off cold air when preheat was required.
>For the price of one wire coathanger and the base of an icecream
>tub, I fixed the problem. It's worked for several years now.
>
>The fuel rail is btw close to the head on my car - it holds in the
>injectors, so it gets quite warm.


hehe = these VW's <g>, my stepfather had a beetle back in 75, he was
endlessly redoing/cleaning the carbs - don't know why, he had that
whistling exhaust drove my mum crazy...

Rgds

:) mike

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