Using DSMLink for Water/Alky Injection...

[Enraged78]

Hey all,

I recently had an idea on how to better implement a water injection system using DSMLink V2. Currently, DSMLink disables the fuel pressure solenoid and instead uses it for Nitrous control. The nitrous control function is actually quite robust, and allows the solenoid to activate the nitrous using RPM, TPS, and knock functions. This seems to me like a perfect and simple way to control a water/alchohol injection system. Here's my thought:

Use stock windshield washer resivour, plumb in 100 PSI pump, and plumb the hot wire from the fuel pressure solenoid into a relay which controls the pump. The pump would mount next to the resivour, and the water line would run to the intercooler piping before the throttle body elbow, with an aquamist nozzle installed. This would actually be very simple and clean, and should work well. However, I have a few questions.

1.) Would it be worth it to have relay control AND solenoid control in this system? Have the hot wire from the solenoid turn on the pump AND the solenoid, and this would ensure proper pressure has been built up in the line, and would prevent too much water from continually being injected when the pump is turned off (bleed pressure). The water line would naturally be run through the solenoid as well.

2.) Is the water hammer or check valve necessary if using a relay and a solenoid?

3.) Is this all overkill, and should I just use the hot wire from the FPS to drive the relay to the pump?

Any thougths or suggestions would be much appreciated. I will construct this and take pictures when I'm done, so the group can benefit from yet another W/I system writeup.

Thanks,
Matt.

[98spydert]

Originally Posted by Enraged78

1.) Would it be worth it to have relay control AND solenoid control in this system? Have the hot wire from the solenoid turn on the pump AND the solenoid, and this would ensure proper pressure has been built up in the line, and would prevent too much water from continually being injected when the pump is turned off (bleed pressure). The water line would naturally be run through the solenoid as well.

It's worth it to run a solenoid because you maintain pressure between the pump and nozzle and their is virtually no delay from when the solenoid is triggered and when the nozzle actually sprays.

2.) Is the water hammer or check valve necessary if using a relay and a solenoid?

The check valve is necessary if you don't have a solenoid. If you do have a solenoid, you won't need the check valve because the solenoid is closed when you're not spraying.

3.) Is this all overkill, and should I just use the hot wire from the FPS to drive the relay to the pump?

I wouldn't trigger power to the pump at all. Keep the entire system powered when you expect to use it and trigger power to a solenoid.

If you have DSMLink, check out the DSMLink forums. This has been discussed many times and lots of people use it. Saves you the trouble of running any sort of Hobbs switch.

[Enraged78]

Originally Posted by 98spydert

It's worth it to run a solenoid because you maintain pressure between the pump and nozzle and their is virtually no delay from when the solenoid is triggered and when the nozzle actually sprays.

That makes sense. Thanks.

The check valve is necessary if you don't have a solenoid. If you do have a solenoid, you won't need the check valve because the solenoid is closed when you're not spraying.

Again. This makes sense.

I wouldn't trigger power to the pump at all. Keep the entire system powered when you expect to use it and trigger power to a solenoid.

Wouldn't this burn out the pump? The decent pumps put out 100+ psi, and I'm not sure the system would be 100% leak free if this was on all the time. I would like to use this whenever my foot gets the heavy urge, and keep it moderately simple.

If you have DSMLink, check out the DSMLink forums. This has been discussed many times and lots of people use it. Saves you the trouble of running any sort of Hobbs switch.

Didn't even think about that until after I posted here. There's a bunch of posts on the DSMLink forums, but most people are discussing progressive controler solenoid use, which is a little beyond what I need right now. It's good to know that this is not a new idea over there. Seeing as how I'm only running a 14b, maybe the FPS control with a relay and a check valve is just what the doctor ordered.

Thanks,
Matt.

[Enraged78]

I re-read Twitch's tech article, and you're post suddenly makes more sense.

Do it yourself WATER INJECTION!!!!!

The Sureflo 100PSI pump will automatically shut off once the pump is primed. So, I can use the fuel pump relay hot wire as the relay signal for the pump. When the car is on, the pump is on, and the system is primed. Very nice.

When DSMlink sees that parameters for the solenoid have been met, it energizes, and everything works. The Sureflo kicks back on because pressure is down, and everyone is happy.

Sounds like a great new project. I might also add a top feed resivoir to complement the stocker. Should allow for a few more gallons of water/alch to feed from.

I like where this is going.

Thanks,
Matt.

[Enraged78]

Dupe post. Stupid connection.

[doug]

I'd definitely be interested in that writeup you mentioned earlier after your install is done, should you decide to implement this. I've been looking into a WI system more and more lately, and already have DSMLink V2.