Water/Methanol Injection

[Joseph Upson]

This is a good short and to the point example of the dual nozzle benefits:

http://www.turbobuicks.com/forums/alcohol-propane-nitrous/80025-good-read-pre-turbo-injection.html

[AleroB888]

..................... Depending on how well it does that you may not benefit from an intercooler by the time the second nozzle kicks in to add its contribution to the combustion process. This depends on when you start spraying, the later the more beneficial the intercooler to the air passing through before injection.

If injection starts at 1 to 2 psi the overall cooling effect maybe equal to or greater than what the intercooler alone provides or at least made that way by the time you deduct for intercooler inefficiency due to drag/obstruction of the air passing through it.
That's apparently why some have found they no longer needed the intercooler and removed it altogether after the addition of a second nozzle.
A simple datalog of air temps with intercooler vs. dual nozzles and no intercooler could determine the need for the intercooler. ..........................

I will make it a point to test the theory once it's installed. I would run the intercooler regardless as a safety in the event of an injection system failure.

My experience was that to get the greatest benefit of either system, use one or the other, but not both intercooler and ALC injection at the same time.

The intercooler would limit the effectiveness of the first spray nozzle for two reasons: it would show more psi loss flowing a mixture rather than dry air, and it would tend to condense the mixture, which would add heat back to the system. Granted the intercooler would drain off that heat, but if the mixture condenses enough, it would pool and create even more psi loss.

Leaving the intercooler in for safety, I don't know. What about just modding the Spark vs. IAT table?

I think if you work at it, you will come up with a good injection system. Of course, the key is timing the two nozzles and being able to vary their output rates. If I understand you correctly, you will cut in the second injector as the first one cuts off?

[Joseph Upson]

My experience was that to get the greatest benefit of either system, use one or the other, but not both intercooler and ALC injection at the same time.

The intercooler would limit the effectiveness of the first spray nozzle for two reasons: it would show more psi loss flowing a mixture rather than dry air, and it would tend to condense the mixture, which would add heat back to the system. Granted the intercooler would drain off that heat, but if the mixture condenses enough, it would pool and create even more psi loss.

Leaving the intercooler in for safety, I don't know. What about just modding the Spark vs. IAT table?

I think if you work at it, you will come up with a good injection system. Of course, the key is timing the two nozzles and being able to vary their output rates. If I understand you correctly, you will cut in the second injector as the first one cuts off?

I haven't read anywhere that what you describe is what happens when the two are used together. I've read that boost pressure increased from its previous setting with the preturbo nozzle installed. The mixture evaporates inside the compressor housing and unless too much is being sprayed it doesn't pool at the intercooler. The preturbo nozzle is much smaller than the secondary nozzle, usually around .75-1 gph as opposed 3 or more, so the air is cool but not wet like what's going into the throttlebody.

The size of the intercooler also comes into play. If the air charge leaves the compressor housing at or close to ambient temperature there is no need for the intercooler, sort of what I implied in a prior thread, however, if injection is not being activated for several psi like 5 for instance, then the intercooler is beneficial in place in that it will probably be removing a considerable amount of heat from the unsprayed boost pressure, increasing overall power under the curve.

Starting with a good intercooler with less than 1 psi pressure drop for your boost level should still compliment the system. If the intake charge is being sprayed at a very low pressure you'll be refilling the tank frequently, something I don't want to have to do.

If my system is set to spray at 7 psi, I will need the intercooler because my datalogs show inlet air temps more than 212 deg by that time without the intercooler. With it temps dropped by more than 100 deg by that point which in theory is good for ~10% increase in power.

[Schmieder]

There is a net effect with the addition of dual nozzles that is apparently equivalent to or greater than what the intercooler alone is offering on a street car if I read closely enough about the GN.

Of course I'm speaking of water/meth install on an engine as a benefit, not to treat an already knocking engine. It doesn't matter how well it works, several people on the Fiero forum still refer to it as a band aid partly because that's what Corky Bell called it decades ago.

A few questions about water/meth injection...

Under boost, where is the greatest amount of pressure? By the turbo compressor, throttle blade or just behind the intake valves? Reason I ask is placing the intercooler for increased efficiency. If there is greater pressure in the system closer to the compressor, I would place the intercooler closer to, like wise if it is closer to the TB the same

Also noting intake charge expansion areas. Knowing when a gas expands it cools, so any place during the intake there is expansion the air charge is cooled. Would a water/meth nozzle be best placed during intake charge expansion or compression?

Compression is obviously where the heat is introduced but spraying water/meth into a charge that is expanding should accelerate evaporation...thus accelerating the cooling action. Or would the vapor charge condense into large water dropplets when the intake charge expands?

In Short, where is the BEST place(s) to place a water/meth injector?
Should I polish my intake with a rough wall for boundry layer turbulence (just how fuel vapor is treated) to keep water in suspension and prevent wall beading?
Is there added benefit to have a dedicated water/meth injector per cylinder just like Fuel Injection? Or keep it just prior to the compressor?

Please excuse me gentlemen, I am German blood and I have to dissect everything, understand it. I don't like bolting things on and not knowing the fine details/science of the mechanisms.

[Joseph Upson]

A few questions about water/meth injection...
Please excuse me gentlemen, I am German blood and I have to dissect everything, understand it. I don't like bolting things on and not knowing the fine details/science of the mechanisms.

What are you doing in PA. and what more does being German have to do with wanting to know in detail other than just wanting to be informed for good decision making regardless. No need to answer that.

You are asking of individuals what can best be served with more targeted research for articles on the subject, that way you can get a more thorough description than what most of us are probably willing to sit and type out. Here are a few links:

http://www.alcoholinjectionsystems.com/a40/Where-Do-I-Position-My-Water-Injection-Nozzles/article_info.html

http://www.max-boost.co.uk/max-boost/intake/WI.htm

Look for the calculator toward the bottom of the thread.

http://www.rbracing-rsr.com/waterinjection.html

[heysoundude]

My understanding is that in NA port-injected engines, that a little bit of water vapour/mist displaces some oxygen in the intake airstream, cools it somewhat, and absorbs the heat of combustion when it gets flashed to steam when the gasoline burns, but ALSO expands significantly more than the air it displaces would for a little boost in torque to make up for the loss of the fuel's energy.

I have a water induction system on my daily driver, a 2007 Buick Rendezvous with the 3.5L: (I can add a diagram/pictures if anybody would like)
It's a simple bubbler tapped into the PCV line between the front valve cover and the port behind the TB on the Intake manifold, with an aquarium bubbler stone at the bottom on an intake hose that breathes the hot air under the hood to better aerate the water supply, and a needle valve on the output to regulate the vacuum leak it introduces to the MAP sensor. on the MAP sensor signal wire, I've added a pull-down resistor (10-turn, 10kohm) to compensate for the vacuum leak. (so the ECU doesn't overfuel because of the extra oxygen from less fuel exhaust it sees at the o2 sensor)...the H2 component included in H2O might have something to do with things too.
using this in the summer, I get an extra 100+ miles out of my tank using about 4oz of water, and it doesn't feel any different to drive. I've never been brave enough to drain the 16oz of water in the 32oz bubbler vessel I use over an 18gal tank of fuel, but as long as I can offset the MAP reading, I suspect I'd improve on those 100+ miles...and to be clear, I only use distilled water rather than water/meth, which is why the summer-only usage (I live in a place that water usually freezes in winter)

that's my $0.02 - in my experience, It works as I have it implemented. pumps and nozzles and wiring seemed a bit over the top to see if it made a difference, and now that I see it does, I don't see the need to get crazy.