Joe Perez

iTrader: (8)

Recently, I'd noticed that my rate of consumption has been down quite a good deal. IOW, I haven't had to fill the tank for a while. Did a pressure-test on the system and found that the pump was operating normally, so I pulled the nozzle out of the inlet pipe to inspect it.

Now, we all know what a normal, healthy nozzle looks like on the inlet side, right?



Right, it's got a cute little filter screen, made of stainless steel, around the inlet to prevent foreign matter from clogging the delicate little hole in the end. Well, here's what mine looked like:



WTF, right? Where did the screen go? After a brief search, I found most of it at the bottom of the nozzle assembly, clogging the hole that it's supposed to be protecting:



Nice, eh?

This particular nozzle was purchased from one of the major kit vendors, and has been installed on the car for about a year and a half. I've been running about 1/3 methanol to distilled water, which is certainly not an excessive amount. And yet that little screen simply disintegrated. Can't imagine how long it would have lasted were I running 50% methanol, as is the case with the "boost fluid" sold by most of the WI kit companies as being compatible with their systems.

On the plus side, I hadn't re-mapped my ignition table since moving from CA to FL, and apparently that 93 octane gasoline is some pretty good stuff as I hadn't been getting any knock. On the minus side, this was the one failure more that my failsafe system couldn't detect, and of course, it's one that I never expected to happen.

Needless to say, I'm done with Meth. From now on, it's pure water. That, and apparently I need to advance my ignition a bit more.

sixshooter

iTrader: (12)

???Methanol doesn't eat steel??? Did it rust or what?

miatamania

iTrader: (9)

Wow. Strange.

Joe Perez

iTrader: (8)

Methanol does have a corrosive effect upon regular steel. Stainless is supposed to be impervious, though just how impervious depends upon the grade used. One supposes perhaps that these nozzles are made with the cheap stuff.

NA6C-Guy

iTrader: (1)

Wow, dat iz teh gayz

magnamx-5

iTrader: (7)

one more reason i dont use nozzles with screens good catch man im glad you saw it before bad stuff happened.

ZX-Tex

iTrader: (15)

Wow.. gonna check mine tonight!

Joe, on a related question, I have been looking for a flow switch as a fail-safe guard for the WI. I think if a I ran a flow switch in series with a pressure switch (on the pump outlet) that it would guard against just about any type of WI system failure:

Line rupture or leak - flow, but low pressure
Clogged line or nozzle - pressure, but little or no flow
Low or empty tank - no pressure or flow

In your quest for developing the ultimate WI system I am wondering if you found any small, inexpensive flow switches that toggle at low flow rates, like 3-6 GPH. Not a meter, just a switch, like a paddle switch type. I have been looking, albeit somewhat casually, and have not found anything yet.

I want to redo my WI failsafe to use flow and pressure monitoring on the pump outlet, and have it trigger timing retard on the ECU. I know how to do it all, I just need the flow switch.

Thanks in advance.

UrbanSoot

iTrader: (24)

why do you even run meth? meth is good for substituting for fuel but water is WAY better at cooling

sixshooter

iTrader: (12)

Damn. I knew it would promote rust but didn't really think it would eat steel. Well, I learned something today.

Joe Perez

iTrader: (8)

I've looked around, but haven't found any simple (and affordable) flow switches that will be effective at the low flow rates we use. For a system which uses any kind of progressive control, you'd really want a flow meter anyway, as you need to be able to discriminate between a partially blocked nozzle and the normal reduced flow at lower injection rates.


One word: Bandwagon. Everybody else was, there was lots of hype, so I felt I needed to. Besides, we can't leave Tom with a monopoly on the use of plenum-injected fuel as a coolant, now can we?

In the time since, I've been doing a fair bit of reading which indicates that water, by itself, is a highly effective anti-detonant, and I simply never got around to purging the system. It's done now, and it's going to stay that way.

Anybody here know why all those smart fellows in white coats even bothered with methanol back in the 40's during the heyday of liquid-injection research? Antifreeze. They tested a whole bunch of different alcohols, and methanol just happened to be the cheapest and most widely available that they could find to stop the water from freezing up inside the tanks and lines on the aircraft when they were parked on the ground. (During flight, waste heat from the engines was used to warm the fluid.)


Corrosion + pressure differential + flow = the damn thing just fell apart. I found several semi-coherent but corroded bits of the screen in the bottom, and one little sliver of wire that was partially protruding out the hole. I'm guessing that during the initial stages, a lot of the smaller bits just shot straight through the nozzle and were inhaled by the engine.


I'm still running a filter screen on the new nozzle, I'm just not going to pump corrosive liquid through it any longer. We'll check back in another year and a half, but my feeling is that this one will probably fare much better.

Joe Perez

iTrader: (8)

Also, a note on pressure switches.

I had previously been using the switches that Devil's Own sells, the ones that look like this:



I've had two of those switches fail on me. Both times, the plunger locked in the fully extended position, forcing the switch on all the time. Not the way you want a failsafe switch to fail... Figured it out when I noticed that changes made to my Spark1 map weren't having any effect- the ECU was being forced into Spark2 all the time.

I am now using a genuine Hobbs brand switch, which looks similar to this one:



I got it on eBay for about $15, so it's both cheaper and appears to be much more robustly constructed. There are dozens of different models and most are adjustable within a wide range by removing a rubber cap on the back and turning a screw with an allen wrench. I set mine on the bench (using compressed air and a regulator) to close at 35 PSI, giving me a setpoint of 20 PSI above system pressure (you have to account for MAP pressing against the outlet side of the nozzle) which should be a reasonable turn-on point.

magnamx-5

iTrader: (7)

Boost Pressure Switch - For Turbo Water Injection hobbs:eBay Motors (item 230364469681 end time Aug-12-09 15:11:12 PDT) i use these nvr had a problem to date.

ZX-Tex

iTrader: (15)

Damn it, I have TWO of those. One to trigger the WI, one as the failsafe switch. Sticking plungers FTL. That might be a motivator (among other things) to go to Adaptronic controlled progressive WI. That or use the switch you pointed out. Thanks for that BTW. I have seen those before, good to know they are working well for you.

My water consumption rates have not been horrible, so I may just stay with the simple single stage on-off system for now. Really though, to do programmable progressive WI, all I need to do is go buy a less than $100 IGBT/SSR (packaged, with supporting circuitry and terminals) and wire it to the Adaptronic. Done. The Adaptronic has fully programmable PWM outputs, just need the IGBT/SSR to provide enough power to the pump.

Also, good point about the flow switch. That would not work for progressive WI. I had considered that. A flow meter would require some feedback monitoring to compare commanded versus actual flow to work as a fail safe, and that is beginning to get complex/expensive I think, unless you have any ideas.

Even for single-stage on-off WI, a flow switch would work best if it was matched to a particular nozzle, or at least within a small range of nozzle sizes.

Ultimately, there is no inexpensive and/or easy substitution for periodic nozzle inspection I suppose.

gospeed81

iTrader: (51)

Just ordered one...exactly what I'm looking for.

y8s

iTrader: (8)

joe is there enough flow velocity / pressure drop in there to cause cavitation in the screen? perhaps it simply aerated itself to death.

thymer

iTrader: (5)

Not super cheap but how much did you spend on your engine and is it important to you?

IFS-30C - Injection Fail Safe - Combo

Joe Perez

iTrader: (8)

Cavitation? I'm pretty sure that the water in those lines is moving at sub-sonic velocity. And there's really no question that the debris which I fished out was seriously degraded beyond what mechanical stress would cause. I'm sure that the force of the water moving through the screen was a contributing effect, but without corrosion weakening the screen, I doubt seriously that it would just distintegrate on its own.

I have to imagine that exposure to methanol may have played a role in the failure of the switches as well. I have always mounted them up high on a long line to prevent liquid from entering them, but there's not much you can do about vapor working its way through the line and entering the switch. I'm just hoping that the newer, more robust switch, along with an absence of methanol, will improve its chances. Hell, this system only has to hold together for maybe another 6 months and hopefully it'll be gone altogether.


Periodic inspection is a good idea. Not running corrosive chemicals in your system is another.


The gadget that Thymer posted is a good idea so long as you have a controller capable of reading and responding to it. I intend to implement flow monitoring of that nature in my next system, just wish I could figure out who the OEM supplier of the flow metering device inside that box is. I can't find a good source of inexpensive flowmeters right now.

thymer

iTrader: (5)

This is not interfaced with any controller, that's the point, it's standalone. The box looks for flow. When there is flow it outputs 12V which triggers a solenoid. This solenoid then allows your boost controller, MBC, whatever to raise boost pressure above base.

y8s

iTrader: (8)

what is the possibility you accidentally made a methanol fuel cell and it just ate the stainless?

IcantDo55

iTrader: (11)

I don't have meth on my Miata but so on my Stang. I don't use and saftey switches but I did move the air intake temp sensor in line with the meth so it directly cools the sensor and tune to a temperature and if its over that temp it pulls timing. Its fail proof because you are not depending on floats and such also of lines get clogged for what ever resin it does not cool sensor it pulls timing.

I'm running straight 100% meth. Put some meth on your finger and some water, tell me what feels cooler???