Nozzle spray angle...

[jondee86]

Thanks for the input rotrex

If the water is more effective in the cylinders as droplets rather than
vapour, then it makes sense to move the post-charger nozzle closer to
the inlet manifold. I'm not sure which position you are recommending, so
I have marked them here...



On top of the last bend would give a straight shot into the manifold, and
probably separate a fair amount of water out on the manifold floor. However
this will find its way into the cylinders no problem as the engine is installed
with a slight slope.

Will it make any significant difference if the nozzle is mounted radially to
the bend, or axially to the following tube ? Same situation applies to the
pre-charger nozzle.

Cheers... jondee86

[rotrex]

I'd take the right position, maybe a bit further left, say 2cm, so the spray mostly points into the pipe. You might even point the nozzle straight down into the pipe towards the manifold.

The left nozzle position would likely lead to a large percentage of the droplets hitting the outer walls of the pipes creating more of a wall bound fluid stream than mist.

Water vapor does little for you power wise, it actually costs power. You need it mostly as fine fluid droplets in the cylinder.
For methanol this is less of an issue. Most will evaporate even just hitting the hot inlet valve. There has been research done on comparing ethanol port injection vs direct (in cylinder) injection regarding charge cooling effect.
http://www.aquamist.co.uk/forum2/vbu...eferrerid=6624
They found that much of the ethanol seems to evaporate hitting either the inlet valve or the cylinder walls (cylinder, head and piston crown) before the intake valve closes. It rather cools the metal than the inlet charge and does little to raise the knock limit by means of in cylinder charge cooling. It still raises knock limit due to its chemical properties aka high octane number.


That can be a good thing, too, say for a heat sensitive motor lacking piston oil jet cooling or a rotary engine.

One more suggestion. Mount nozzle threats for both positions and compare what gains you the most power after ignition tuning. You will find that the ignition advance requeirements will be rather different for the two positions. The position that needs the most ignition advance to restore full power got the most water mist into the cylinder. With the engine being out of the car this is very easy to implement.

The more methanol your mix contains, the less the nozzle position matters.

[parmas]

Nice explained Rotrex. I like your thinking style makes me wonder of an updated revision on mine for my next high compression build...

[jondee86]

OK... I think I'll go with the in-line (back of the bend) location. Should be
easy enough if I can use these nozzles...



As suggested, I will position the nozzles a little bit towards the incoming
airflow to try and keep as much water off the walls as possible. Having the
tip of the nozzle projecting a few mm should help a little as well.

@ Richard L
I don't see the extended nozzles anywhere on the Aquamist Direct site. Can
you confirm that they are selected the same as standard nozzles ?

Cheers... jondee86

[rotrex]

point it towards the opening of the intake plenum, so straight down

[jondee86]

I'm thinking something along these lines would work ?



Should be easy enough to make a couple of aluminum bungs and have
them welded to the tube. I don't have a lot of clearance on the intake
ducting, so I would have to check that there is enough room for the longer
mounting detail. Right angle fittings should work.

EDIT: Due to the amount of messing around involved in mounting the
nozzles in-line, I am thinking that I will just put them at 45 deg as shown
in the revised sketch. Since 99% of people mount them straight in the
side of a duct and it works, mounting in the corner should also work.

Also means I can use standard nozzles with a button welded on the tube
and tapped M8.

Cheers... jondee86

[jondee86]

@rotrex Actually, looking back at the advice you gave in this thread...
http://www.aquamist.co.uk/forum2/vbu...1006#post21006

I am starting to think that port injection may be the easiest/best solution
to ensuring even distribution of water. This picture shows that there is more
room under the fuel rail than I first thought, and it should be possible to tap
a nozzle into the top of each runner close to the injector.



This location will avoid water pooling on the manifold floor, and bypasses the
question of how best to mount a nozzle in the ducting. My research to date
has not found any urgent reason to spray pre-charger, other than when
using the car for sustained high speed operation (racing). So I will probably
put that on hold for now. It would be a simple job to add a 5th nozzle at a
later date.

I have a couple of questions regarding the best nozzle and fitting setup for
port injection...
1. Do I need checkvalve nozzles ?
2. If so, what is the lowest height option for a right angle connection ?

Cheers... jondee86

[Richard L]

Originally Posted by jondee86

@ Richard L
I don't see the extended nozzles anywhere on the Aquamist Direct site. Can
you confirm that they are selected the same as standard nozzles ?

Cheers... jondee86

The extended nozzle is only available in the "internal checkvalve" version.

.

[parmas]

Originally Posted by jondee86

@rotrex Actually, looking back at the advice you gave in this thread...
http://www.aquamist.co.uk/forum2/vbu...1006#post21006

I am starting to think that port injection may be the easiest/best solution
to ensuring even distribution of water. This picture shows that there is more
room under the fuel rail than I first thought, and it should be possible to tap
a nozzle into the top of each runner close to the injector.



This location will avoid water pooling on the manifold floor, and bypasses the
question of how best to mount a nozzle in the ducting. My research to date
has not found any urgent reason to spray pre-charger, other than when
using the car for sustained high speed operation (racing). So I will probably
put that on hold for now. It would be a simple job to add a 5th nozzle at a
later date.

The Aim of injecting Pre-Charger is to increase the efficiency of the charger if by any means you are already working out of it's efficiency range. Also for setups without intercooler (like me) that don't have long piping giving time to evaporate and cool the air mixture. Tried and tested and works without problems.

I have a couple of questions regarding the best nozzle and fitting setup for
port injection...
1. Do I need checkvalve nozzles ? RECOMENDED
2. If so, what is the lowest height option for a right angle connection ?

Cheers... jondee86

Having the setup port injected will not affect the air mixture thus no cooling is being made. I would still make at least one nozzle post charger to gather that extra hp from a denser mixture.

[jondee86]

Hahahahahah... just had a look at what a port injection system costs
So an end to thinking out loud. It is always possible to upgrade, so for now
I will go with a basic two nozzle system... one pre-charger and one post-
charger. Standard nozzles installed at 45 deg in the bends as per the above
sketch.

From what I understand, placing the post charger nozzle further from the
inlet manifold would help the cooling effect, but increase the chances of
water being centrifuged out of the airstream. Placing it in the last bend will
reduce the time for cooling, but allow more water into the cylinders in
droplet form... so perhaps the better option ?

The pre-charger nozzle appears to be less critical as the charger "mixes"
the air and will not be sensitive to droplet distribution at the inlet.

The only question remaining is whether it is necessary to use one (or two)
checkvalve nozzles ? There will be some pressure differential between the
nozzles, so draining could occur during out of boost driving. However, there
will only be about 0.5 metres of 4 mm tube between the nozzles, and this
should not create any significant delay between activation and spray ?

EDIT: Oh,and one last question... what would be the recommended water
split be between the pre and post charger nozzles ? 25/75 ?

Appreciate the input as I like to examine the alternatives

Cheers... jondee86