Water, water everywhere...DIY?

[210Tumbleweed]

Okay...One for the masses, older-skool wrenchers to the new wave techies.
93 IDIT Factory 093
I've been looking at a lot of different ways (including looking 'round OB) to get a LOW Budget water injection setup in the SuperDuke, and I'm almost there...How low you ask?
At this point I have invested a lot of time...learning about flow rates, injector spray paterns, droplet size, single vs multi stage design, constant vs progressive pump control...thermal coefficients of expansion, and even latent heat of evaporation somethin-er-other...
And I don't have the means, just right now to...fffwhtt!!!...pull $500-900 US outta my pocket (or anywhere else) for a buy-N-fly system.
What I do have is one- 12vdc 160 psi, 8L/min pump; two-Danfoss 240vac constant duty solenoids; seven- 3/8" pushlock x 1/8" mnpt nickel-over-brass fittings, two 3/8" pushlock bulkhead unions;

AND

One commercial grade BUNN coffee maker, that has been eviscerated...soon to be TIG'd up on all seams, with appropriate holes added for lid, vent, out and return flow....the math says it'll hold 7.43 US gallons.

>The crux of my problem is nozzle/flow calculations and flow control. I just ain't quite getting it. I'm no math-magician...if there's anyone out there, on here, that could or would kindly chime in and bless me with a nugget o' knowledge...

 

[Thewespaul]

Do you want to know about different nozzle options or do you want to wire an arduino and control the solenoids duty cycle to control how much is injected?

 

[210Tumbleweed]

A baseline nozzle size for a single stage setup...until I get a better understanding of two stage; and the Turbo rebuilt. Would be great!

What/How's an Arduino figure in?

 

[210Tumbleweed]

I'd considered trying a...please don't LyAO...electronic brake controller (like for a trailer) taking the return spring out and monitoring pump pressure to determine flow?

 

[210Tumbleweed]

Uh...maybe I missed something.

Solenoids are NO/NC ?
Pumps have duty cycle?

I could be wrong in my understanding of control schemes...most everything I've read says one or the other.

 

[Thewespaul]

To make things simple, forget the arduino for now, as well as the trailer brake controller.

This is the nozzle I started with on my water **** setup years ago, I don’t remember the flow rating but it did well. I bought it off McMaster Carr, and I’m running the next size up currently.

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If you want to know your absolute flow, then setup everything the way you would with it in the truck, and bench test the system. Catch the fluid in a container while running it for 60 seconds, and measure what is injected. This will give you a flow amount with your specific setup. I don’t have a need for ramping it in, or for changing nozzles much so I kept my setup simple. Pump comes on with ignition, and once line pressure reaches 150 psi the pump shuts off automatically. A set of relays open the solenoids to allow flow and are triggered by a nitrous micro switch. This is mounted under the gas pedal and closes when at wide open throttle. This sends power to the next switch, which is an adjustable Hobbs switch. This allows you to have the injection to only occur when the engine has boost, which will help vaporize the mixture, and give you another layer of insurance.

 

[Thewespaul]

Duty cycle for solenoids is just a rapid opening and closing of that valve electrically that is used to regulate flow by adding the restriction of how long the valve shuts vs how long it is open, hence the “cycle”

 

[210Tumbleweed]

Cool...yeah... I've got an adjustable Hobbs (1-15lb), 10 ft of vinyl tube, and a check valve on the way.
If you're not using that noZzle in the photo...?
Or what size do you think would be a good starting point? I've been holding off ordering any...due to my lack of understanding on sizing.

 

[Thewespaul]

Yeah take it, it’s been sitting in my box for years

 

[ISPKI]

That brass nozzle from mcmaster is the same one that I am using for my setup. They get very very small, I picked up a few in the lower size range to test out.