I would run a Peak and Hold injector driver just to be on the safe side, it keeps the powerfc happy.

I was going to use the same type of setup but was going to do the following

2X 1600cc in stock Sec location
2X 460cc (Water Injection)

This will give you about the correct ratio of Water/Fuel and when you are under light boost they will not be online as long at the Sec injectors are not firing.

When the Sec injectors start to fire then the motor will start to get water from the other 2 injectors @ the same Duty cycle of the Sec injectors

Stock Injector output_____/-------- Injector Driver (FJO Driver)--------------Sec Fuel 1600cc
Sec Front Rotor. . . . . . . . \_____ Injector Driver (FJO Driver)_________Water injector 460cc

Stock Injector output_____/-------- Injector Driver (FJO Driver)------------- Water injector 460cc
Sec Rear Rotor. . . . . . . . . \_____ Injector Driver (FJO Driver)_________Sec Fuel 1600cc


Any Questions?

 

^ I've considered a similar setup. what are you using for the water injectors?

 

I am going to use stock NA FC injectors, I have tried them with the alch/water and it doesn't seem to have a problem with it.

 

^ i like your thinking how long did you try them for..... what % mix will you be doing it pre or post turbo? any other info on this setup or is it still floating in your mind im very tempted to run a similar setup if i decide to go the pressurized route, currently i want to run a mechanical injection setup pre-turbo.

But i believe the injection setup running stock injectors directly off the ecu at 5-20% sized injectors for the water vs. fuel would net you the best control over injection eliminating the bogging at lower rpm full boost on/off swith applications currently out there. minus the ones with mappable control which still dosent give enough control in my opinion.

for my setup i was planning on running 2 water/alc injectors pre and possibly post turbo.

stock fuel
---------rx8 450-470 primaries
---------4x yaw high imp 1000cc secondaries

water/alcy
---------1x 75-200cc inj preturbo running off primary signal
---------1x 100-400cc inj post intercooler running off secondary signal

now to be able to run the water/alcy injtors i was looking at either going fjo box tapped off primary and secodary to run just the water injectors OR an EIC/AIC setup with a larger injector so that i can adjust the % of total injection with a simple spin of a **** possibly. i need to look into those still.

but i think the easiest way would be the fjo running the water/alcy inj with a hobbs switch to turn them on at the preset PSI.

z

we should probably have a seperate thread to discuss this

 

I moved some of the discussion that was happening in another thread to its own thread.

 

Here is my ideas

Either one of these would work, it is just how you want to do it.

This one is if you want to cool all the incoming air


This one is if you want to only cool the secondary intake runners, and have the primarys just run thru without water.

 

think you could upload to the forum those pics i cant see em here behind my filter. if not ill see em in a couple days.


but iv been thinking on how to run the water injectors and being i can run the 1000cc's without the additional FJO driver, what i kinda stole/came up with/ like is running a solid state relay off the primary and secondaries signals to run the additional drivers as i want to maintain the same duty cycle percentage, itll make measuring the % of fuel to water easy as choosing the injector that is that percentage. like say 4000cc fuel = 400cc water for 10%.

the solid state relays cost around 8$ per and have plenty of speed to match the duty cycle. much cheaper than the driver box. ones ive been looking at have a response of 15khz something like 33 microseconds to open 33 to close with a draw oh 0.020 ohms draw practically nothing.

But after thinking about it that way id have to run a smaller injector off both signals for pri/sec for a total of 4 inj reason being as youd only have half the fuel from half the signal for fuel duty as the injectors signal is based of firing duty of only one rotor not both. i suppose you could always double the injector size used off the one signal to get the correct water %......

thoughts?

im thinking of steering clear of an EIC as it is usually based off RPM not load like your fuel injector

z

 

I had considering a similar setup, but I was told that normal fuel injectors will rust quickly unless you run 100% methanol.

 

it hasent been done much but there are people running this type of setup just far and few between for info.

most of them for the "rust" issue run 50/50 without issue and for more piece of mind they are searching out the flex fuel injectors with stainless internals. i still feel like most of these claims are people scared to try so id like to at least try. for a better piece of mind a alcohol soluable oil pre mixxed just like fuel should provide no issues i have some extra injectos laying around and a fuel pump so i may set up a controlled test once i treturn stateside to test these theories.

z

 

Are you hell bent on 4 methanol injectors? I know it's the best for atomization, but it will add complexity.

 

I agree with everything you said, I didnt even think about a flex fuel injector, the only reason I was thinking about the FC Stock NA is because I have alot of them laying around. The Alk/Oil I have heard of and would be a good insurance policy.

I am debating on a return fuel system like the stock fuel injection system works or a one way feed, but if you get air into the system it would be harder to remove it from the system, it comes down to complexity of the system you want to build.

It really doesnt matter, 2 or 4, the issue is if you have the fuel rail setup it would not be that much harder to install 2 more injectors, you all ready have the fuel rail and a injector box.

I guess i wanted to add the water to all the runners, I could move the injectors upstream and reduce the number of injectors but that means less atomization like you said.

 

I've already put a lot of thought into this kind of setup, but again I was worried about regular injectors not working with methanol so I shelved it. At this point on straight pump gas I have more power than I can put to the ground with my crappy tires so it's not a big priority, but I'd love to give you ideas for this.

If you had 4 methanol injectors and you wanted the PFC drivers for them, you'd have the two secondary injector drivers running 6 injectors total. I think that's pushing it.

You're basically plumbing a whole separate EFI fuel system to do this right. Fuel injectors are designed to run at constant pressure relative to manifold pressure, so for the most consistent delivery you'll need a fuel pressure regulator as well and you'd want to match it to the base pressure you're using for the regular fuel system. http://aeromotiveinc.com/products-pa...***-regulator/ is a regulator with NPT inlets if you don't want to spend money on stainless hose. And as we've already discussed, you need to find an injector that will work with whatever fuel you choose to use. And a regular EFI injector is not going to work with 100% water for long.

For the fuel itself, if it were me I would go with straight denatured alcohol or something else that is readily available. Mail ordering methanol is a pain in the *** and you will get tired of it after a while. You don't want to be in a situation of "crap, I'm reluctant to do x with my car because I don't have enough A/I fuel readily available today." That's what I went through when I used to run race gas 100% of the time on my old setup. I know people freak out about safety for storing anything more than 50/50 in a tank but what the hell, you've already got 100% gasoline running all throughout the car.

Now check this out:


http://www.atpturbo.com/mm5/merchant...Category_Code=

Now where could you mount these so they would clear the hood? You might be able to put two at the beginning of the manifold, one where the primary runners join and one where the secondary runners join. But you'd have to check fitment as I said. The other option is one bigger injector (you can get up to 2200cc topfeed now) mounted to the TB elbow and driven off one of the secondary drivers in the PFC. Buy an FPR and then run it all to a pump and tank. I would consider the single pre TB injector idea. It would have the advantages of a full EFI system but wouldn't cost too much or require that much custom wiring or plumbing.

 

im looking at exactly this almost at the elbow or just before. but running something like the FJO or possibly the solid state relay wont put a load on the driver like just a straight additional injector from looking at it the addditional load for the relay would be like .02 ohms not sure on the FJO. especially if only running one additional injector for simplicity it could be pretty large just running off one rotors signal farther up the air stream allowing more time to mix with the air.

although i still feel better if it was ran with 2 injectors instead the one off the secondaries at the throttle body elbowish and then one either pre-turbo or just post-turbo to get maximum cooling of the air charge. these would be efi controlled but with a hobbs switch just to be sure they wont fire while cruising in upper rpm's when the secondaries come on out of boost.

z

 

I would be concerned about driving a fuel injector by just running power and ground to it through a relay. That's like running it at 100% duty all the time, it may hurt reliability of the injector. The solenoid inside a normal fuel injector really isn't designed to be run that way.

 

i fail to see what your saying that is the exact way an injector is run minus the 100% duty you stated.

heres the thing the stock injectors run a constant positive firing to ground through the ecu giving duty cycle obviously. now running the solid state relay it can match the response of the driver from the ecu so it will operate at the exact same specs as being driven directly off the ecu so it is still running in its designed fashion unless iv missed something.

input?
z

 

I agree

Duty cycle means the amount of time the injector is on/firing

With the way you stated, you would be giving the injectors the same signal as the stock injectors. I haven't delt with a solid state relay so I can't say about if it will work corretly.

 

i havent delt with the SSR's either but looking at specs of some random ones close to the range we would need it looks to work on paper and for the price i will be willing to start testing it come feb once im stateside again.

z

 

.

 

Make sure you check the switching time first...

https://www.rx7club.com/showpost.php...1&postcount=24

- Sandro

 

you guys know that Aquamist offers an RX-7 specific, fuel injector duty signal summing module that reads both primary and secondary injector duty, calculates overall duty, and controls a water injection PWM high speed valve matching this duty and also outputs a 0-5V signal for logging or other uses you find for it, right?

 

yes but some people will go to great lengths to reduce the number of boxes and separate controllers they have in their car. that's why I went through a lot of trouble to make the Power FC control my boost on a single turbo.

 

i would have to agree entirely.... imm finding it hard to do all the add on boxes to make the pfc work with all the additional support we like to use. its definatly hard to justify the 450 boost controller the 150+ injector controller, 600+ ai controller and so on and so forth.

i actually have an AEM 1900u full standalone at the house im so close to talking myself into installing and selling the PFC as its just not enough of an ecu if you want more than just a stock style setup.

after looking at everything and where i sit it may just be time to do the swap over and sell the entire PFC setup lol. whats the going price of a PFC, commander, datalogit, harness w/ less than 3000 miles BRAND new basically? 1800ish ya thatll easily pay for the engine harness clips and solenoids to control all this plus the additional "boxes" i would have needed with the PFC and id still have cash left over im thinking...... hmmmmmm


Sandro

as far as the response there are other much faster SSR's out there like in the .5 microsecond hell even .5 milisecond would be acceptable as long as it has the same turn off time it would just lag that much. but i agree 50-100 miliseconds is way too long. but .5 microsecond response is pretty close to perfect if you ask me ill find a link to some examples in a bit.

z

 

ok for updates to anyone interested i will NOT be pursuing this any farther. reason being i will be running the aquamist hsf-3 system which is literaly exactly this setup we are discussing to include the HSV which operates at speeds speeds capable of a fuel injector 250hz as well as having a high imp driver to be ran directly off an ecu if you wanted 13ohm.

but after thinking it all through i believe this will be the least hassle most cost effective route for what i want. i will most likely be running 3 nozzles as well 1 pre-turbo and 2 direct port or at least in the upper intake manifold in both secondary ports.

z