DIY, cheap water injection

[b4black]

I'm gonna give it a try.


I have a washer bottle with a built in pump from an '88ish Grand Prix. I mounted it with a angle braket where the charcoal canister was. The ground and switching is easy. Just alligator clip it to the boost light swicthes. When it lights, pump goes on.

I still need an igintion power source, a way to control the pump speed and a nozzle for spraying. It will be spraying above the carb.

 

[fc227]

How electronically inclined are you?

Also one of those “hot rod” or “car craft” articles showed an under the carb hat injection system.

 

[b4black]

One concern I have heard is about impeller erosion when injecting prior to the turbo. This page from Dawes Devices comments on that. http://www.dawesdevices.com/howto.html

The nozzle: Most people that I spoke to who have made there own water injector have used a small orifice that "squirts" the water into the mouth of the turbo. They rely on the turbo to completely atomize the water. The problem with this is that it is highly abusive to the compressor blades. Eventually, it will errode the leading edge of the blade, just like a sandblaster. If you are using this system primarily as a means to increase fuel, rather than for cooling, you may need to resort to the squirt method to get enough fuel. Multiple misting nozzles could achieve a higher flow, but the complexity would be prohibitive. I used a misting nozzle from McMaster-Carr (www.mcmaster.com) to atomize the water prior to the turbo and avoid this problem. Of course, you need a pretty high flow nozzle to equal the volume of the "squirt" method. I used part # 3178K87, which is nickle plated and has it's own filter screen. By atomizing the water prior to injecting, so far there has been no visible wear. You will need to monut the nozzle in an elbow with a hose nipple on the other side, to allow for the fluid input. I had to search the bins at the local hardware stores until I found some elbows that would clear the nozzle's screen. Cost: about $3 for the elbow, about $5 for the misting nozzle, and about $6 for ten hose nipples (Mc Master #5346K11), you will use the nozzles elsewhere on this system.

Injecting ahead of the turbo allows you to use a low pressure pump (i.e. cheap washer pump). Spraying ahead of the carb will help atomization and prevent the water from being sucked in at vacuum.

 

[Baron Von Buick]

Ok it may be dumb question but what the hell is Water injection?

 

[Ttype83]

Originally posted by Baron Von Buick
Ok it may be dumb question but what the hell is Water injection?

The only dumb question is the one not asked.

Quoted from Dawes page:
Water Injection Facts:

When increasing the boost level of a turbocharged vehicle, an undesirable byproduct is an increase in intake temperatures as well as a corresponding increase in combustion temperatures.. These higher intake temperature increase the chance of detonation within the cylinder. The best solution is to add an intercooler when the boost pressure exceeds 12 psi, but this is not always practical due to cost and packaging limitations. The early Chrysler TI (drawthrough) turbo engines are a good example of packaging limitations. It is somewhat difficult to fit an aftermarket intercooler to the factory manifold. This makes it a good canidate for water injection.

Water injection decreases the possibility of detonation by lowering the combustion chamber temperatures and increasing the effective "octane" of the fuel. This allows the engine to run a higher boost and full spark advance without the use of race gas. Additionally, if the water is atomized in the intake stream, there is an additional cooling of the intake charge. Both effects are increased with the inclusion of 50% alcohol to the mix (don't spray the exterior of an intercooler with alcohol!, this refers to internal injection only). The additional fuel of the high octane alcohol will in turn allow boost beyond what the factory fuel system can deliver.

Water injection also has the effect of "steam cleaning" the combustion chambers and exhaust valves. This removes the carbon build up that decreases efficiency and leads to pre-ignition(detonation). It will also keep the throttle body and interior of the intake manifold much cleaner than normal.

 

[Baron Von Buick]

Wow, Thanks, That was like an ending to a G.I. Joe Cartoon, Well
Now i know and "Knowing is half the battle" Thanks for the info it was very helpful, now when people are talking about it i wont be scratching my head.
Thanks
Patrick

 

[b4black]

Fred, I can handle most simple electronics . I re-read both those articles. Both used aftermarket kits.

I don't think I will need to control the pump speed. It looks like the injection rate can be controlled with the nozzle orfice size. I will probaly order some of the McMaster water mist nozzles referred to on several website.

I haven't read about any problems with methanol and washer pumps. I think the alcohol in washer fluid is methanol, so they should be OK.

 

[b4black]

OK, made a little more progress.

Found a ignition-switched power source - the white wire to the wiper motor. Just need to tap into it.

Got the McMaster water misters. They are kinda big. I fit a 1/8" npt coupler to it and then a barb fitting. Instead of drilling a hole in the carb bonnet, I think I can mount it in the hole where the thermo-swicth for the air cleaner is. Then it will spray up into the air stream just ahead of the carb. The incoming air should be more than enough to suck it into the carb. (Instead of spraying down into the carb from above.)

Washer bottle and pump (used) - $8.00
Mounting Bracket (angle aluminum and hardware) - $5.00
Hose - $ 0.50
Mister nozzle - $4.00
Coupler and barb fitting - $2.50
Check valve - $1.00
Eletrical connectors - $1.00

Grand total - $20 (not bad )

Actually I bought four different sized mister nozzles at $4 each. Still pretty cheap.

 

[b4black]

It's working.

I haven't upped the boost yet. I just want to get a feeling for it first. It is lowering the knock I was seeing at 11 psi, but there's still some during shifts. I'm not injecting much yet.

The clear tubing I first used would get soft when hot and loosen on the fittings. (The pump creates 30 psi.) I went to black vacuum hose and hose clamp on the fittings.

50% ethanol - 50% water. 30 psi and a M5 nozzle. This would be a about 2 gph (one-fifth of the M15 @ 40 psi mentioned above)



http://www.mcmaster.com/catalog/109/html/1883.html

 

[Peter]

How much water? Check this.

http://www.snowperformance.net/installation.htm

 

[b4black]

I started out with a M5 size nozzle turning on at 8 psi. After testing I was running two nozzles (one T'd into the other's line) and turning on at 3 psi. As the nozzles get bigger, the pumps pressure decreases. Lower pressure = less flow. In other words, twice the orifice size does not flow twice as much if the pump can't maintain pressure.

Aslo, turning both on at 3 psi is a lot of alcohol at low boost (especially on the street at part thottle). It would be nice if the alcohol amount would increase with boost.

Easy solution. Two bottles with two pumps. One to each nozzle, so there isn't as much of a pressure drop. And each pump can turned on at different pressures. (one at 3 and the other at 8 psi).



My brain's was on a roll.

I decided no need for three washer bottles under the hood. I removed the stock bottle and moved the pick-up hose to one of the alcohol/water bottles. With the stock bottle out of the way, it becomes a great place to mount the MSD box. The box matches up exactly with the holes for the stock washer bottle. Now the MSD box is mounted, and I didn't need to drill any holes.