cheap water/methanol injection any adivice guys?

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I remember there being a really good water/methanol injection thread but cant find in search. So i had a few questions i hope someone could answer, keep in mind that this is a budget setup not pro aquamist setup or anything like that .

1.What are the pros of mounting the spray nozel on the intercooler pipes before throttle body vs. mounting it between air filter and turbo.

2.Lets say i use the pressure of the plenum to push water from the tank to the nozel, but i use a solenoid switched on at 14psi+ (anything less no water gets to the nozel). What disadvantage am i facing over using an electric water pump?

3.How much water becomes too much water (i nkow this is dependent on engine load), say i use a 140ml nozel at max it will be 140/slightly over how on earth will i know when to stop increasing. Am i in any risk of hydrolice/hydrolocking the engine?

4.How much leaner can you run the fuel mixtures, whats a good a/f ratio (measured at muffler tip)?

5.I have not seen these cheap brass irragation fittings but from the picture it seems they do not have any sort of threads on the tip of the fittings, so there goes the idea of welding a bung to the intercooler pipe and simply screwing it on, what have you guys done to fit brass fittings to alluminium/stainless pipe.

6.Whats a cheap recomended pump apart from shureflow

7.Is there any damage to the engine running a water/methanol injection that i should be aware of? From what i read so far its all pros.

8.I'll be running at themostat around the throttle body area for testing whats a good temperature to start activating the system.

[jmac]

I'm generalising this to buggery. Some of the water injection based info isn't etched in stone, it's generally what's believed to be going on. There is more to it, I've concentrated on just a couple of things.

1.What are the pros of mounting the spray nozel on the intercooler pipes before throttle body vs. mounting it between air filter and turbo.

It'll depend on what specifically you'll be running - water, methanol, or a mixture of both.

If it were straight methanol, then for the most part it's 'good effects' are not in the cylinder, but on the way there. It sucks tremendous amounts of heat out of the intake charge, making it denser, but also lowering it's temperature, so it won't pre-ignite during the compression stroke.

For most street cars (this isn't true for tractor pull turbo diesels that have been boosted beyond 200psi, well beyond) where the turbo compressor discharge temp isn't insane, water does it's work mostly in the chamber. Yes it will take some heat out of the intake charge on the way through. But the amount of heat energy water absorbs to get to 99-100 deg C is relatively modest. However the amount of heat energy to get it from there to actually change into a gaseous state is massively disproportionate. So the work it does can actually occur as the incoming charge (already hot from the turbo compressing it) is being further compressed by the piston coming up.

A quick note here. The reason that with the same fuel you can XX compression (say 10.5:1) safely, or can run 8:1 and 15psi boost (which would actually give an effective comrpession well in excess of 10.5:1) and _not_ detonate is simple. The turbo is a substantially more efficient compressor than a piston, so it heats it far less to compress it to the same amt. Add in the fact the chamber will be quite warm from previous combustion events, and the fact that water actually does most of it's work in the chamber is a good thing. It's also thought that while it's along for the ride, when it gets super hot, ti expands considerably (perhaps more than just the burning charge relatively) so it might even sort of have some small increase in power, and possibly spoolup.

Having said all that, I'm personally not a big fan of injecting anything before an intercooler, simply because there's a reasonably good chance of it condensing or pooling in the core. It could end up leading to a big enough puddle, that if picked up due to a wierd incline, and a sudden rush of boost (say you'd been caning it, then drove normally for a while, then nailed it again) it might get enough in the cylinder to hydraulicise it. Not a definite, but worth concern.


2.Lets say i use the pressure of the plenum to push water from the tank to the nozel, but i use a solenoid switched on at 14psi+ (anything less no water gets to the nozel). What disadvantage am i facing over using an electric water pump?

Possibly a slight delay between when it sees that pressure and when it's delivering the water etc. There's a much easier way. Most spraying gear has the option of very cheap inline valves. They basically shut off automatically below 3psi, and won't spray again till the water is above 3psi (or whatever figure). That way you wouldn't need a solenoid

The main advantage of a pump (like the one you mention at least) is that it can flow big time, at a high pressure, so it's no trouble at all to add the water after the intercooler, it'll still spray with big boost pressure (you can even route a hose from before the throttle body to the tank, so it automtically preloads the tank and the delivery pressure is automatically raised with boost.

3.How much water becomes too much water (i nkow this is dependent on engine load), say i use a 140ml nozel at max it will be 140/slightly over how on earth will i know when to stop increasing. Am i in any risk of hydrolice/hydrolocking the engine?

Very very very roughly,a small (say under 2litre) four would have a combustion chamber space about 35-50cc (that's chamber, plus gasket volume and the piston dish if any). At 4000rpm, being a 4 stroke, it's actually doing 2000 complete cycles per minute. At a minimum, assuming you could somehow magically only deliver the water to one cylinder, then you'd have to deliver 50cc x 2000, or one litre of water per minute at 4000rpm to completely hydraulicise it. I am fudging the figures, as obviously there would be some fuel in there etc, but you get my drift, it's actually bloody hard to do unless you go ridiculous. Of course if you dumped in about 1/10th of a litre, and it managed to get there in one cycle, it'd lock up easily. But a smooth consistent spray that totalled about a litre a minute would be needed. Anyone feel like doing the exact math?

Don't take the rated flow of a given nozzle for granted, set it up in a bucket or something (or mark the reservoir) and run it and see how long it takes to get a litre into the bucket.


4.How much leaner can you run the fuel mixtures, whats a good a/f ratio (measured at muffler tip)?

If you are looking for peformance, don't lean the mixture, unless it's currently at something stupid like 10:1 on gasoline based fuel, it's counter productive, and risky. Presumably you are running quite high boost and pump fuel, frankly I wouldn't suggest leaner than 12.5:1 for starters, and only go leaner if you really know what you are doing, and can accurately measure it. Too many people have lost engines trying to 'outsmart' the basic properties of the fuel, and the boost levels they are chasing. If you are definitely going to run methanol and water, you can lean out the mixture a touch, if you are game, but not by very much, as you'd have to replace the 'missing' petrol with methanol. Methanol likes an a/f ratio about twice as rich as petrol (and is happier at far richer than that) so you'd need twice as much. Then factor in that it might be a 50/50 methanol water mix. You'd have to basically spray in 4 times as much water/methanol volume as the volume of petrol you'd be taking out (roughly speaking) so it's a shitload.

5.I have not seen these cheap brass irragation fittings but from the picture it seems they do not have any sort of threads on the tip of the fittings, so there goes the idea of welding a bung to the intercooler pipe and simply screwing it on, what have you guys done to fit brass fittings to alluminium/stainless pipe.

There's fittings available to screw or clamp them to a flat surface with a hole in it, or other options. Check at the place you buy the nozzles from (I can probably point you toward a place in Melbourne if it helps)


6.Whats a cheap recomended pump apart from shureflow

nfi. Not many efi fuel pumps will last long (if at all) with water. some can. If you are looking at spraying pre turbo, where you won't need massive pressure, some of the windscreen washer pumps will do enough. The ones that are sometimes used to spray headlight lenses on some luxo cars etc actually have a much higher volume and pressure capacity (nothing like a shureflow though) and would be the pick of the 'cheapies'


7.Is there any damage to the engine running a water/methanol injection that i should be aware of? From what i read so far its all pros.

Probably the biggest one potentially is that methanol isn't particularly friendly with a lot of metals, and fuel system components. Holley carbs for use with them run diferent spec needle and seats (mostly for twice the glow), and acc pump diaphragms for starters. Most engines that are run on it for drags or sprint cars, or even jet boats don't leave the methanol in there. After the race meet, they drain the methanol, then fill the tank with normal pump fuel. Then they run the engine till it's blowing copius amounts of smoke (since it'd be supplying twice as much fuel as would be needed for gasoline, with methanol jets) then shut it off, as that means the methanol is completely flushed out.

Some washer spray bottle/motors won't hack it, some will, only way to know is to find someone who's tested your particular choice, or 'suck it and see' - perhaps by dropping the pump into a jar full of methanol and seeing what it does.

8.I'll be running at themostat around the throttle body area for testing whats a good temperature to start activating the system.
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Although temperature is critical, it's not the only issue, and it's what it does just prior to combustion that is probably the most important. If I were in your shoes, I'd start with too much water (not enough to lock it up, perhaps something approximating the amt of fuel that would be delivered by one injector at 100% duty cycle for a 4cyl for example. Then cutting back on it, till you get the best performance with whatever boost/fuel you run, thne going back a touch bigger with the water/methanol.
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There's been a few discussions about this on the jyturbo mailing list, and I'd highly recommend joining and reading the relevant stuff in the archives. The current threads are actually about methanol and nitromethane, and some of the more interesting stuff I've read on the net in some time. If it's of any interest, I'd again recommend taking a look. A quick caution though, the list is not for the feint hearted. It goes off topic a lot, but the discussions are actually very well articulated. There's not much tolerance for people who 'demand' it be on topic or that a question that's been asked a million times is not answered and the asker is too lazy to look in the archives, but for anything else, it's gold.

John McKenzie

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thanks for the detailed reply, certainly cleared some things up. I was intending on a water-methanol 50-50 setup and leaving in the car permanantly and it only being activated above 14psi. But after reading yours and a lot of other comments about methanol damage, i think i might reconsider. Could you leave me with the melbourne supplier of nozel fittings.
Cheers