How is pump pressure/volume controlled and mapped with a WI

[PK4]

I have a Sureflow 150/100 PSI pump, a hand full of nozzles of different sizes & most other bits & bobs to make a rudimentary WI setup. But, I would like to have a progressive system at a minimum, (I have a couple of AIC?s auxiliary Injector controllers that read manifold pressure and tach signal and fire off a 7th fuel injector that Ideally I'd really like to adapt one at some point.) But for now:


What is involved in a simple progressive system? I know they feed off of manifold & vacuum/pressures, what sort of signal do they put out ( a varying 0-12v ? a pulsed 12V signal? An amplified low voltage signal? And to what? the pump directly?

I read a (4 yr. old) sticky here and was lost after a few posts. Fundamentally, how is the nozzle volume/ pressure of a progressive WI system logged & modified? And what is controlled by a controller to vary the H20/meth to fuel mix?

What tools required to tune and measure the proper amount H20/meth to fuel ratio/timing? Canit be pick up on laptop OBDII know how to calculate nozzle capacity & I read something about exhaust gas temp, is there a device to read that temp without stabbing a probe into my headers (surface mount?)


My car is a 99 Porsche Boxster; 2.5L, 11:1 comp, ratio, Eaton m63 blower, 4.5 PSI boost, AIC w/ 500cc fuel injector, 260+/- hp (60 hp boost) at crank.

Thanks in advance, PK

[wred]

Most Progressive controllers send a pulse width modulated +12v or ground signal to a shurflo pump. Flow is controlled by the speed of the pump's rotating internals (known as pps or progressive pump speed). Others also send a pwm signal (+12v), but to a high speed solenoid valve (such as aquamist 2s, 2d, HFS-5, coolingmist s-hsv) or a piston-type pump (perrin). The high speed valve performs similarly to a fuel injector, opening and closing rapidly to alter flow, while the piston-type pump changes the frequency of its pulses to alter flow. They are more costly, but have more range as well as being much more precise and linear (in terms of flow) without sacrificing good atomization. Here's some more reading you can do:
http://forums.nasioc.com/forums/show....php?t=1393721
http://forums.nasioc.com/forums/show....php?t=1413320

Pressure is only regulated in a hsv setup. In pps kits, flow varies in accordance with pressure. Pressure in hsv applications is maintained by either a pressure switch or an internal bypass valve. Max flow rate is normally altered via a change in nozzle size (archaic, I know), but of course there are other possibilities.

Typically people inject 10-15% of fuel fluw, although I'm not sure if that's for water/meth mixtures. If you spray only water, you should inject less.

Often times stock sensors are inadequate for doing anything other than driving your car. Just to give you an idea, I know in my wrx the map sensor loses resolution at 22 psi, egt sensor doesn't really measure egt, and the iat is useless since it's before the turbo. It may be different in your case, though. Also, depending on what program/device you use to pick up readings from the OBDII port, they may not be useful due to a slow update rate or certain incompatibilities with your particular car. As far as the external mount egt sensor, I don't think such a thing would work well since the heat retention characteristics of various metal can differ, possibly skewing your readings.

[PK4]

Thanks Doug,


Thanks for the very insightful reply. I?m surprised you were able to handle my buckshot load of questions.


So If a Sureflow takes a sort of PWM type signal from a controler to control it?s speed and the HSV does essentially the same. What is difference the frequency that each runs at?

One of of the threads mentions a pulsed drive on the sureflow shortens it's likfe, true?

My spare AIC (auxiliary injector control) will put out a pretty well-metered PWM signal (I guess) to run and meter an auxiliary injector and thus , an HSV (? same frequency?). I know people have run a HSV from an AIC. I assume though that the pump would need to run on a far lower frquency than a PWM signal for a fuel injector or an HSV (no?)

I?m also going to guessing the PWM controlled pump is not terribly accurate, does it need to be?


BTW, I did get a hold of an EGT with (2) probes. Looks like a pretty easy install.

Thanks again,

PK

PS. Nice articles, informative.

[wred]

Sorry for the late reply. I don't visit this site often and I forgot about this thread.

The possible frequency range of the hsv is much more narrow than the shurflo pump's. It can only operate at 100 Hz or so, MAX. This is because the width of every pulse must be long enough for the valve to fully open and fully close. Depending on what hsv you use, this takes approximately 3 ms. If the frequency is too high, the valve will simply stay closed at low duty cycles, and stay open at high dc's. It will not be able to modulate flow variably.

The shurflo pump, on the other hand, is not restricted in this way. The pump simply needs to be on long enough for the motor to begin moving. Because of this, the shurflo pump can operate at much higher frequencies.

I don't have first-hand experience with the shurflo pump's longevity in pps kits, but it makes sense to me that it would wear out quickly from the constant changes in pump speed.

As mentioned earlier, the pump can actually operate at HIGHER frequencies than a fuel injector/hsv. You MIGHT be able to use the AIC to control a shurflo pump, but the pump will need to draw 10A from it. If it's not designed to provide that much current, you could fry the AIC. Otherwise, it should work. However, the AIC will be perfect for a hsv.

You are right, a pwm controlled pump is not that accurate. People do get away with it, though. But since you already have something suited for controlling a hsv, that would definitely be the path I recommend. It will be much easier and less costly to go hsv now rather than going the pps route first.

I am in the process of building my own WI kit from scratch. If you need any advice on parts (where to buy, how much, part #s, etc.), feel free to ask.

[PK4]

Originally Posted by wred

Sorry for the late reply. I don't visit this site often and I forgot about this thread.

Been awhile, forgot about this forum to. (What forums do you hang out at?) Building WI from scratch, sounds interesting. Thanks for the offer regarding parts. I may in fact need some nozzles but I think I?m set for now.


I?m still bungling around a bit. Turns out for my "six" the aic fires at between 35-300HZ, from idle to redline respectively, or once per ignition fire. No valve that I can find is capable of that. (Except a fuel injector, more on that later)

I got another AIC for fuel, supposed to be pretty good. It has two mappable outputs. One is a PWM signal for the fuel injector and one is a 1-5v analogue signal (convenient, both channels being under 1 software hat).

The analogue V. (with an amp.) could, I guess, be used with a progressive valve or pump, or go through a PWM converter to run an HSV valve (not sure how well this works, seems sloppy, frequency still needs to be dealt with).

But I still have another AIC (which means more software to deal with and to tune). But it would be independent & exclusive to a HVS, meaning I could set it up to fire at a more reasonable frequency. I picked up a little trick: lower the AIC freq. and use multiple injectors spaced upstream to avoid gaps in the H20 saturation during the course of a cycle (not crazy about adding more holes, bungs and nozzles though)

Yet another wrinkle, there?s a guy who uses regular fuel injectors (which I guess can handle the high frequency) for WI ( www.myo-p.com/ ). I?ve seen elsewhere where a 50/50 meth mix really inhibits corrosion of pretty standard PWM valves (frequency still an issue).

So, My options are:


1) Use a second AIC, retuned frequency to run an HSV (need two nozzles (??), 2 software packages to tune)

2) Use second AIC with a standard fuel injector for h20 ( corrosion, not clear how big an issue, car sits a lot though)

3) Use 1 AIC, covert 0-5v channel to PWM (has one interface, requires a converter with It?s own static tune or it goes up to 300 hz & uses fuel injector).

4) Same as above but amplify 0-5 channel for proportional valve or proportional control of pump ( not terribly accurate (but does it really need to be))


Thoughts, comments, ideas?

Thanks for youre reply,

Regards, PK

[wred]

I was always under the impression that the open/close time of an injector was about the same, if not slower, than a hsv... how long do you think it takes for an injector to open/close?

I know this doesn't have much relevance to the topic at hand, but I was wondering; where are you getting these extra injector controllers, who makes them, and how much are they costing you? If I have understood your post correctly, you have 3 AIC's? My controller cost me almost $300, and I have the impression that the ones you're getting are more robust. If you let me know the name/part# of your extra injector controllers I can help you figure out which would be best to use.

Whether or not a hsv is capable of keeping up at 300Hz is dependent on the width of each pulse at higher frequencies. If the duty cycle at that point is at or near 100% (which it should be), the hsv's inability to open and close repeatedly is negated. I am inclined to say a hsv would be suited for your 35-300Hz AIC.

You are right, the 0-5v output would work if you had a converter such as this. Although it would be ideal, for obvious reasons, if you could control the hsv directly from the AIC.

I'm not sure I understand your "trick." Are you contemplating running multiple valves (one for each nozzle)? Or are you suggesting each nozzle be at a different max flow rate? I wouldn't recommend this, just because it's so much more difficult to detect a failure when you have multiple nozzles.

You're right about the corrosion issue with fuel injectors. However, there's an additional problem; i don't think fuel injectors are designed to operate at high pressures (100+ psi), which is important because the meth/water droplets need to be small enough to vaporize completely by the time they reach the combustion chamber. For some reason, either fuel doesn't need to be as atomized or pressurized... I'm honestly repeating what I've heard concerning this matter though, so don't take my word as gospel.

Are you actually running extra fuel injectors? If so, how many, and for what purpose? Fill me in on some of my questions, and I'll help you make a decision from there.

Btw, I normally hang out at nasioc.com and wrxtuners.