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Water Injection now testing ....


JimAttrill
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Well, I finally got it all wired up. The delay is because I hate wiring anyway, and the thought of taking my Mud Console off to add the switch was not my favourite job.

Wired a buzzer and a switch into the relay switching circuit and voila! I had a buzzer that worked at the pressure set by the switch. But no water as the pump wasn't running.

What I found out from a workmate who understands volts and such elecktrickery, was that my buzzer was cutting down the current to the relay, so the coil would not operate.

So, took the buzzer out of the circuit and now with great trepidation, I am driving it. The problem is, without a buzzer or a light I cannot tell when the pump is running. Oh well....

I haven't blown the motor up yet, and really want to see if I get lower EGT and fuel consumption. Forgot my stopwatch so I can't really test it before and after yet, will do so tomorrow if the head stays on :)

P1310089Small.jpg

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Water injection into the intake???

I hope it atomises properly otherwise it'll be like sucking water through an intake when wading, and we all know what that does to diesels :o Still, its common on very high performance race petrols, and of course wanna-be chavs!

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Wired a buzzer and a switch into the relay switching circuit and voila! I had a buzzer that worked at the pressure set by the switch. But no water as the pump wasn't running.

What I found out from a workmate who understands volts and such elecktrickery, was that my buzzer was cutting down the current to the relay, so the coil would not operate.

So, took the buzzer out of the circuit and now with great trepidation, I am driving it. The problem is, without a buzzer or a light I cannot tell when the pump is running. Oh well....

Use an LED instead if the buzzer... current draw is very small then. Otherwise, put the buzzer in parallel to the pump on the other side of the relay... might have to use a resistor to get the voltage across is right though?

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If you put a buzzer, or LED, in series with something, then you will be limiting the current flow to that device massively. You want to put the buzzer in parallel with the relay or pump. If you use an LED, I'd put a normal diode the opposite "wrong" way round across the LED to prevent voltage spikes killing the LED.

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I was cheating really. With the buzzer in-line I only needed one wire to the dash. With it in parallel I need two more wires. So if I wire the buzzer in parallel on the relay switching wire it will not stop the relay from working? That I could manage without taking the dash apart again as I allowed plenty of slack in the wiring.

For those that didn't see my previous post, the thingy in the foreground of the picture is a purpose-made atomiser sourced from the US, and the thingy with the wires attached is an adjustable boost switch. The pump is a headlight washer pump from a Disco. They grey thing in the pipe is a VDO non-return valve.

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Well, the pump is made to pump water, so it should last a week or two :) If that fails I have another one lying around, and if that fails I have the HP side of a TD5 fuel pump which pumps water at a fair pressure. Though I suppose it would prefer to pump diesel. The US pump was a whopping $120, too much for me.

What's wrong with the Bodgelok thingys? We use them all the time to avoid cutting wires.

I hate electrical stuff, did a bit for my apprenticesship. I was taught it, but can't remember learning much at all. Got as far as Fleming's left hand rule which I found interesting as I am a left-hooker, but for the life of me can't remember what it was about.

Thanks for the link, I'll try to understand it sometime this evening. Maybe have a couple of beers first :blink:

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Scotch lock (or IDC - Insulation Displacement) connectors are horrible. they work by piercing the insulation with a barb, which is used to carry the current.

The trouble is, if/when the barb only just nicks the copper, you have a very poor connection with high resistance, which when carrying current will generate heat, melting the wires and starting a fire. even a 'perfect' fit will still have poor performance, due to the limited surface area of the barb.

I would never ever use them, in a vehicle or anywhere else. Call me pedantic if you wish, but i despise them as an unsafe and poorly executed method of joining wires together.

In summary, they are the work of the devil :P

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My only concern with water injection is that you're injecting water into a pipe which is at (up to) 1 bar, so you might find the pump stalls (and burns out eventually?). The good news is, no water = no difference, so your engine is safe from this effect, but if the pressure difference allows some water to pass, but not enough nozzle pressure to produce a spray, you could end up ingesting gobs of water through the inlet valves, and this would be bad.

My conclusion - I'd try to visualise the water spray pattern against 1 bar first. My crude experiments suggest that a water cooler bottle will hold nearly 1 bar pressure(!) and lemonade bottles probably similar levels, so you could poke your nozzle through a bung in the bottom of one of these, use a workshop compressor to pressurise it to 1bar (or whatever max boost you're running) and visually inspect the spray pattern. That way you'll know that the washer pump is able to deliver into that environment.

Otherwise, with the setup you've got, you might just find no difference on the road (except an annoying buzzer) and you've got plenty of water left when you get home. Either way, I applaud the experiment, it's an exciting idea. Are you using pure water? If you use the methanol-based screenwash you could see even greater performance benefits.

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To be really pedantic, IDC works well on wire that's designed for it. 90% of the UK phone network is IDC, but we use wire that's a single solid conductor and of calibrated copper & insulation thickness. That ensures everything works as it should. There's probably 10 or more IDC terminations in the average phone line from exchange to your phone.

In cars, with normal multi-strand wire and scotchloks, I agree they are just bloody awful things and should be avoided at all costs. Before anyone asks, solid cored copper wire isn't ideal in situations where it's subject to vibration / movement.

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Methanol based screenwash is an interesting though, another possible could be acetone, it has been known to increase the fuel burn in diesels thus increasing efficiency :)

I use a fair bit of acetone (Propanone) in my work; it is miscible with water, but almost instantaneously denatures and 'swells' rubber (both synthetic and natural) and dissolves many plastic items, so do please be careful if tempted to experiment with it around those expensive engine components. :blink:

Perhaps, use of a industrial alcohol solution with water (e.g: Isopropyl Alcohol...aka: "Rubbing Alcohol") might also yield the effective 'evaporative' temperature reduction you`re looking-for, without the corrosive effects of a Acetone or Methanol. ;)

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I use a fair bit of acetone (Propanone) in my work; it is miscible with water, but almost instantaneously denatures and 'swells' rubber (both synthetic and natural) and dissolves many plastic items, so do please be careful if tempted to experiment with it around those expensive engine components. :blink:

Perhaps, use of a industrial alcohol solution with water (e.g: Isopropyl Alcohol...aka: "Rubbing Alcohol") might also yield the effective 'evaporative' temperature reduction you`re looking-for, without the corrosive effects of a Acetone or Methanol. ;)

Some wise advice, however with an injection system into a cast inlet manifold one would hope there aren't any plastic bits or perishable rubber seals between there and the cylinders, but its something to beware of if added to the fuel tank for example :)

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I'd try to visualise the water spray pattern against 1 bar first. My crude experiments suggest that a water cooler bottle will hold nearly 1 bar pressure(!) and lemonade bottles probably similar levels, so you could poke your nozzle through a bung in the bottom of one of these, use a workshop compressor to pressurise it to 1bar (or whatever max boost you're running) and visually inspect the spray pattern. That way you'll know that the washer pump is able to deliver into that environment.

I know I could experiment like this but I have no patience. So it seems that all is working ok - the headlight washer pump seems to push out enough pressure to overcome the turbo pressure. I seem to have used about 500ml of water on the way home where the boost was only enough for about a minute or less.

Stage two will be to fit a larger reservoir draining into the windscreen washer bottle.

Stage three will be to fit a level sensor into the bottle to switch off the pump when the water level drops.

Hey Fridge, I am often pedantic myself, so don't worry :)

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That brass thing you see in the photo is an adjustable boost sensor with an NO (normally open) and a NC (normally closed) connection. So I can adjust when I want the switch to close using the NO connection. When the boost meets the setting, the NO connection closes and power will go through. I have a boost gauge and I used the buzzer to check the actual setting, not really trusting the visual setting on the switch.

The sellers of the switch recommend that I start the water injection at .2 bar but I am setting mine a bit higher, at .5 bar or thereabouts. Max pressure on a 300Tdi is 1.05 bar. So it will not inject water when I lift off or just cruising along at less than about 80kmph (or 50mph).

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Well, I put a light across the pump. The boost switch is set at .5 bar and it is definitely using a bit of water. When I tested the setup with and without the injection on a stretch of uphill and rather empty road close to the workshop, I must say it does not seem to have made much difference even though the engine seems to accelerate better. This could be wishful thinking, rather as your car goes better after you wash it :)

However, I have discovered a 220 litre drum of Methanol in the workshop which was to be used to make biodiesel ....

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Sorry to keep 'bumping' this post, but I have now set the boost switch to 5psi which is about 3 bar so the w/i pump runs quite a lot of the time. It is now using quite a lot of water, and the engine is running fine. I shall try to work out fuel consumption figures soon. Luckily I have a spreadsheet that calculates the consumption going back to when I bought it 240k kms ago. So any change will be easily noticeable.

Haven't tried the methanol yet....

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I wouldn't mention acetone. That is on my banned/snake oil list.

But I have used 2 liters of (cheap) water in the last 77 kms. In that time I would use about 7 litres of diesel. So I want to see if my diesel consumption has improved. I will let you all know.

And I still haven't added any methanol to the water... that comes next

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  • 2 weeks later...

It seems that my fuel consumption has improved quite a bit :)

I have an Excel spreadsheet which calculates all litres/100k figures for the last 240 000 kms, since June 1996. The overall fuel consumption is running at 10.3 litres/100km which is 27.4 mpg imperial.

Since using the water injection I have been getting 9.7 l/100. That is 29 mpg. But I have been driving slower I think because of the current price of diesel. It'll be another month before I fill up again, and I'll post the figure then.

All I can say for the moment is that there is a change, and it is for the better. I am also calculating water consumption and it seems to be about 50cc/km so far. I may need to add a bigger tank as the Defender washer is about 4litres.

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