[dvldoc]

You can think of is like this because the the cooling started earlier along the intake track pulling more heat. If you have 3 foot pipe and start cooling it at 1 in vs a 3 foot pipe and start cooling it at 26 inches tends to count for for the temp difference. Were also talking less than 10 degrees.

Its not the vaporazation that it instant were talking about the mixing of the mist with the air stream that mist hitting that air and surrounding metal is what is cooling. Vapor is hot (evaporated) that is in the combustion chambers.

Theme parks use mist systems to spot cool areas, it drops the temp up to 20 degrees just in that area, that how the initial burst from the system is working,

Vaporization vs atomization (the mixing with the intake air) are two different things. Vaporization will not occur to the mix hits its boiling point and it will not ignite in air until it is at its flash point.

Boiling point: 64.7 C
Flash point: 11 C
Water boiling point is around 100 C (dependent on atmospheric pressure of course) the higher the pressure the higher the boiling point, so you cant have vapor until the fluid reaches the boiling point.

I think of were we got the mix up is the word vaporization vs what we refer to as atomization the mixing of the alcohol solution with the incoming air.

[Terry Syd]

OK, I think I'm getting it now. The methanol will vaporize at 64.7C, that is what causes the biggest drop in temperature in the induction system. Once the methanol goes into the airstream (which has been preheated by the turbo) it vaporizes immediately.

The water will still remain atomized until it is subjected to the intense heat of the combustion chamber, at which time it will then vaporize and become superheated steam.

I then see a subtle difference in the tuning between gassers and diesels. A moderately tuned gasser could use more water to dampen the detonation process and to remove 'hot spots' caused by built up carbon. Further, a gasser for max power can use larger amounts of methanol and water with a larger nozzle to increase octane and cooling.

A moderately tuned diesel could 'carefully' use more methanol in the mix to drop the intake charge temperature and to fill the chamber with a combustionable gas that will aid the combustion of the diesel fuel spray, especially along the relatively cool cylinder walls. The amount of methanol is limited by the point at which the methanol will autoignition in the high compression diesel. However, a heavily worked diesel can use a higher percentage of water in the mix to keep down excessive EGTs.

If that be right, I'm tending towards a smaller nozzle with more methanol in the mix (say instead of 20% maybe 30%) in my lightly tuned diesel. The position of the nozzle being located immediately after the turbo in order to maximise the cooling effect on the intake charge.

I'm trying to conceptualise the principles and applications now, before I start cutting holes and fiddling with nozzles. I hope I'm getting somewhere.

[Pig Bodine]

Yeah, this is exactly what I'm trying to get at. I think that I might have problems with pitting if the water isn't completely vaporized (i.e. in the gas phase) by the time it hits the valves/cylinders even though it may be atomized. The distance needed to do so is what I want to determine my nozzle placement as I care more about the cooling/cleaning effect than any performance gains. In light of this, what do you think as far as placement? If I understand it correctly it is the water vapor that does the cleaning, just like steam cleaning an engine bay...

[Terry Syd]

PB, after looking at the temperatures involved, I don't believe we can get full vaporisation of the mixture. Even if the intake tract air was over 100C, when the methanol hits the airstream it will create a significant drop in temperature. However, since we will be using an M2 or M3 nozzle, then our atomisation process will result in quite fine droplets. Since others with much larger systems aren't getting that fine of atomisation and are using much more water, I don't believe the atomised water droplets will pose any threat to the engine.

I do note that although the methanol may instantly vaporize upon discharge, that there continues to be a cooling effect over longer distances. This additional cooling effect is only a few degrees. I would surmise that this small additional cooling is being done by some of the water being evaporated over the distance. It may not be as dramatic as the methanol drop in temperature, but seems to exist in any case. Therefore, if we are trying to maximise the 'intercooling effect' then a nozzle position right after the turbo appears to offer the best cooling.

Of course, that cross-over pipe on the Yota is quite thin and may present some problems. The last time I had one in my hand, it gave me the impression it was pressed steel. If it is steel, then perhaps brazing a fitting to the pipe won't be so difficult.

[dvldoc]

I would hope your pipe was much stronger than you think, Besides with the nozzles head and bonded washer you have extra surface area to support the nozzle. People put these in aluminum intake tubes as well with no problems. Unless this is some insanely cheap metal you should have no problems.

[Terry Syd]

PB, just to go back to your question about the water vapor, I figure that once the combustion process starts that any water that is still in the atomised state will turn to vapor in the cylinder. Since I am running a 33% vegetable oil mixture with my biodiesel, I'm hoping for the same anti-coking capabilities that you are.

If you check out that thread I started on the boost compensator for the 2LT mechanical pump, you will see that the boost ramp only extends for a set period. Even when I had significant stock pre-load on the diaphram spring the marks left by the metering pin indicated it had run down the ramp, across the flat and then up on the overboost ramp. I've since done the tuning you see in the thread, but I'm confident that even with the 'helper' spring I installed to slow the rate of increase in fuel flow that the metering pin is running off the ramp.

I don't know what boost pressure the compensator is stopping at, it could be as low as 5 psi, but more likely at 7psi. My thoughts on how to tune the WI with the methanol would be to start flowing it at the boost pressure that the compensator quits compensating. This would not only help to prevent any bogging from an earlier injection, but would add additional fuel (methanol) for the remainder of the boost pressure rise when the engine would really need it.

I've ordered the pressure switch with the lowest settings, the one that only goes up to 10 psi. This should allow me the best option to get the WI finely tuned.

[Pig Bodine]

I guess it'll be ok pitting-wise those droplets are pretty small. Does the base kit come with the M2 and M3 nozzles or do we have to special order the M2?

[dvldoc]

All kits come with 3 nozzles, You need to specify M2 as it is a specialty size. And it depends on which base kit you order as well the lowest is a M3-M5-M7 combo.

[Terry Syd]

PB, you also might want to order the SQ 1 pressure switch. It goes from 2 to 10 psi.

Nason adjustable Pressure Switch DevilsOwn Injection

[Terry Syd]

I have been doing some further research on various forums and a fellow on the UK Surf forum came up with this previous post.

Water Injection.
I looked at fitting an intercooler but it’s quite a job on a 3l so I thought I’d try water injection. I bought a kit from the States for £137 including postage and taxes.( http://www.devilsownonline.com ) This is a fairly basic kit based around a water pump from a mobile home and a nozzle from an oil fired boiler but with a small controller that piggy backs the MAP sensor and introduces the water progressively as boost rises. The most complex part of this installation was adapting the nozzle so it could be fitted and removed from the out side of the inlet crossover to allow quick and easy swaps to different sizes and to allow it to be positioned further along the crossover than I could reach if fitting it from the inside. I’ve settled on a 5 Gph nozzle with injection starting at 7 psi and reaching full by 10 psi. With this set up I can get through a gallon of water driving to work and back – 65 miles however in practise I switch it off once up to speed on A roads and it lasts a bit longer. I am try to sort out a larger tank though as at the moment I only have a 5l plastic bottle in one of the rear cubby boxes. Still it’s only tap water so finding fresh supplies is easy.
If you turn the water on when the engine is already boosting you get a real kick and if you’re not already at full boost you very soon will be, the boost comes in much quicker with the water on. I’ve not had the chance to dyno the car with the water on so can’t give any figures but the kick it gives is worth every penny! EGT stays the same in the mid range with the water on and max EGT is down a little but not significantly , fuel economy seems unchanged which considering the extra performance probably means a real terms improvement. Future plans include a larger tank and water/methanol mixes, adding methanol gives more power and lowers EGT. It’s worth noting that with the water and gas on there is practically no smoke from the exhaust even under full load quite the opposite of cars that have had there injection tweaked. The average EGT with the mods is lower so NOx levels should be no worse for disconnecting the EGR, visible smoke is reduced and economy has at least notionally improved so environmentally my car should be better for producing more power not worse and the mods work with bio-diesel too!

To make sense of his post, he had also had an LPG system installed.

So, he used a 5 GPH nozzle, but he was also running a 3L engine and a Progressive Controller. Perhaps a 3 GPH nozzle may be in the ball park for my 2L. I also note that he had not tried blending in any methanol at that point. I'd love to get his later results after trying a bit of methanol.