Hey, I think I'm going to take a shot at this, but if there's anyone good at electronice take a look at this and tell me what you think.

Ebay-1pcs CCM2 10V 12V 24V 30V DC Motor Speed Control PWM Controller Reversing switch

It looks like there is a power in, and a variable speed output. There is a bi direction switch that can easily be wired to a on off switch with out being able to reverse the output voltage.


I am thinking I might be able to supply the potentiometer with voltage from the MAF and adjust it so it starts spraying at a set point, then as MAF voltage rises so will the injection rate.

It is only 10 bucks so I'm going to buy it and do some bench testing, but I was wondering if anyone with more knowledge then me might have an input on it.

 

I tried a PWM controller on mine for a while . Then i read up some more on W/M systems and ditched it .

https://www.rbracing-rsr.com/waterinjection.html

 

You could make it work. The voltage from our maf varies between about 1.25v and 4.5v. Assuming that the main ic's add is set at a 5v reference you should be able to just cut off the potentiometer and wire the maf output directly to the pins on the ic.

Expect that voltage regulator to get hot.

 

Brett

Did you go to direct drive Brett? I could just use a simple voltage switch to activate it, but I was thinking the variable speed might be nice.

Also are you running that 20 dollar ebay 100PSI pump?

LEGO,

Thats kind of what I was hoping that it's a 0-5 Volt control. I've found a few ebay electronics that use a 5 Volt referance.

 

Most do. I forgot to ask, are you using this to control the pump or the injectors? It went be able to control injectors, but I'm sure you know that.

 

Not sure what you mean by that ?
I had a two stage setup and used the vfad wire to control the stages.
Stage 1 was with the pwm controller and stage two was without it.

I'm using a 200psi cooling mist pump.

 

Yeah to control the pump. I'm just going to go with a nozzle or 2 into a BHR throttle body spacer.

My second thought was to place 2 voltage switches so one could turn on the pump and it would supply one sprayer nozzle and have a solenoid activate a second nozzle at higher MAF rates.

 

Like that idea better . Read the link i posted ...........

 

Is is just on and off now without a variable injection rate?

 

If this is going to be your only protection against detonation I wouldn't even consider it. Just based on the manufacturing quality from the pictures it's functional junk, and will fail on you eventually.

 

Actually I've got several different electronics of these sorts and they have been pretty good quality and I have not had a failure from them yet. Granted I don't run them really oftem, but I've used them for long periods of time with out a problem then just throw them in a box and pull them out to work again.

 

If I have understood this right, problem with reducing the flow rate is that this will influence "atomization", or whatever it was called. It is flow that gives turbulent flows that drives the mist- making. If you reduce flow, turbulence is reduced, and mist gets larger particles until the point where solid fluid comes out of the orifice/nozzle.

So to keep the mist with as small particles as possible you must run flat out through the nozzle. Therefore, you should have many small nozzles that is opened from demand(more power = more nozzles).

Sounds logical to me.

 

I was thinking that also, the only reason i was thinking of a progressive controller is that the 3 big companies providing systems all have them. I also don't want to loose power from excessive spray at lower rpm and boost.

Now i am thinking of a 2 stage system where the first one runs when the pump runs and the second one comes online with a solenoid valve. But when running multiple sprayers it will require more flow and reduce the pumps pressure causing the same issue possibly.


Theres only one way to really know.

 

I haven't done any research on how it's normally done, but if you wanted to do multi-stage injection couldn't you just use multiple injectors in a configuration similar to our secondary fuel injectors? It would eliminate the time it takes for a pump to spin up or down from the current speed.

At higher RPM the secondaries could become active, and wouldn't rely on a change in pressure to change the flowrate. YOu also wouldn't have to worry about pump control failure (and you'd have a viable failsafe if injector control fails).

 

I personally wouldn't wire something inline with the MAF voltage without proper filtration and isolation. That's going to open up a wormhole of MAF issues depending on the noise of the adjacent circuit.

 

You would not connect in line, but in parallel. If done in a proper way it will not add noise, it will just act as an voltage(multi)meter. Only thing you would have to take into consideration is that it needs to be very high impedance and avoid ground loops. Should not bee too difficult.

 

Not difficult, but not exactly in parallel...

 

If you are going to measure voltage, you measure by connecting measuring device in parallel with ECU, or over MAF.

Maybe I'm just bad at explaining what I mean.

 

I got you aasf thats exactly how you do it. One wire off the output of the maf. And the voltage switch is already grounded. I have a mag extender harness to tie it into. If theres a problem then i can simply unplug it.

 

No. That would work in theory, and it's an ok idea, but in practice it would never work well. There would still be a large amount of noise being input into the maf signal since cars are naturally very noisy, and dirty PWM signals are also quite noisy.

It would have to be decoupled using an opamp or something similar to avoid mutilating the MAF signal to the ECU.

 

No, I've seen me do it. So in theroy and practice it works great. And No eratic MAF readings.

 

The PWD might cause a problem, but the switch works just fine

heres what I have

All you have to do is remove the photo resistor. Then use a volt meter to determine which pin is the voltage output and which is the input. Then hookup the input to the MAF output. There was no discernible change in the MAF voltage to the car or my MAF readings at idle.

 

Bear in mind that i am not saying that it wont work, but just for future reference if you do experience electrical gremlins, you will want to understand what jitter is and its impact to circuitry and its prevalence in Relays and switches.

Its very commonly overlooked.

 

yeah, I wouldn't have thought of it in that way. I'll admit it. I was more concerned that when I tried it out I was pulling too much voltage from the maf and it would not read correctly. I also have not run it at higher rpm, just some Idle testing, but I figured it would affect the low voltage idle more then the upper end.

 

Hmmm...

Isnt MAF voltage simply read by a ADC at ECU input? If so I do not see why jitter should come into the picture...? To my knowledge, jitter does not appear on an analog signal itself, only in the process of making it digital numbers, or after. http://en.wikipedia.org/wiki/Jitter
And there is always an input filter at less than half the sample frequency, so any HF noise should not make a difference, neither find its way through PCB etc.

Or are your concern that the conductors with PWM output to motor will act as an transmitter antenna, maybe? Keep them short. Alternatively an output filter. If they can make it work close to coil and spark plugs, motor control is a walk in the park compared.