Trying to plan a WI setup
 

So it was only a few days ago that I was considering water injection vs. no water injection, now it seems like I'm considering basic single stage pressure actuated water injection vs. full aquamist with fail safe water injection. I guess I just need some input. I am planning on running 93 octane gas only with max boost around 15psi through my ball bearing T04R (or Borg Warner S362 FMW if I end up changing turbos in the future). This should net me wheel horsepower in the low 400 range.

I don't feel like I'm pushing the engine/boost enough to really justify a $600+ water injection system, but it I want something that is dead nuts reliable since this is technically a track car build. In an ideal world I would get the Aquamist HFS-3 with the RX-7 summer circuit, however because this system will cost much more money that I am willing to spend right now, I am looking at MUCH simpler setups.

Would a standard single stage check valve system for AIS (Devil's Own) serve my needs as well as I believe it should? Was looking at activating the system at 10psi and having two LED's on the dash...one to tell if the system is switched on and the other for the low fluid level.

http://wannaspeed.com/index.php?main...7c4b01c5ed7158

http://www.riceracing.com.au/water-injection.htm

LOL. Good suggestions, but Peter's kit is DEFINITELY not under his "don't feel the need to spend $600" restriction. I'm thinking about getting the Wannaspeed kit this or next month for my setup though, due to its simplicity and reliability.

I am in the same boat as you, but after reading tom94RX-7 recent thread i am going with a simple kit from Coolingmist but with the 200psi pump and a CM5 super atomizing noozle. My goal is 500whp con pump and 100%water with a Precision 6266.

..True & fixed :). There is a few threads floatiing around with part numers to put together a kit. eaiser just to buy from wannaspeedthough.

I like how robust a pre-turbo mechanical system is, but after reading tom94RX-7's pre vs. post turbo WI thread I'm not convinced that I want that extra lag associated with pre-turbo WI.

Lag/Threshold is all relative...

For your needs, I would recommend a simple pump/switch system. At 15psi, you aren't depending on the AI, but definitely benefiting from it being there. It will definitley help with reliability of your engine. A pump/switch system will be inexpensive, and easy.

And for my case? (posted above). I think at any psi i will be depending on it as here we have 91 octane :sad:

You Sir have similar goals as me. For that, I would recommend manual preturbo kit made by Brent or Peter. But I am biased.... I am developing my own kit that is similar.

A mid frame turbo that requires AI to achieve big power will greatly benefit from preturbo. The pneumatic function of the Atomizer Nozzle based system simply makes it more effective, and more reliable. DudemaaaansownRx7 has been making over 500whp at 20psi on the very same kit he sells. Peter has been using this technology for over 10 years with nothing short of killer results.

Can you do it with a pump and progressive system? Of course. Can you do it with a boost fed system and atomizer? Absolutely....

The choice really lyes in your preference. I personally am completely sold on manual preturbo WI. A pumpless system with a single electronic component. I am also using a modified T3 GT35R with a Vmount. Obviously a street setup with spool in mind. Preturbo will work extrememly well in meeting my goals of 500whp.

Awaiting return from my deployment to put the parts together.

Yes, 91 sucks.

So what would it cost to build my own pre-turbo mechanical setup? Anyone have a link to one of threads that just startin was refering to for self built parts?

If I can build a full setup for under $300 that will meet my needs, I would be happy...whether it is mechanical or a pumped system. Once you get to the $400 price range, I would probably start looking at the Aquamist HFS-2 for $500.

Most recent one. READ THREAD, Followed by PM'ing him if interested. My suggestion.
https://www.rx7club.com/auxiliary-injection-173/my-pre-turbo-wi-974884/

Here's a question....as your fluid level in the water resevoir gets low (say below 50% in a 1 gallon resevoir) and their is more air volume, how does this affect the water/air supplied to the atomizer nozzle?

I have to imagine that the air in the tank will pressurize more slowly when the tank gets lower, which will cause the water injection to lag the manifold pressure causing inconsistant water injection during spool. Everything should be fine when the system stabilizes, but I really question the transient consistancy of this type of system.

Remember, I want this for a track application where I need consistant results for at least 30 minutes and enough water to support that time, not a drag race situation where I can top off the tank after each run.

I think I'm just going to end up going with a basic Devils Own single stage check valve system (5 gal/hr nozzle)...should be effective and reliable. Haven't figured out if I'm going to be able to fit the pump and a large enough tank in the engine bay yet or what size tank will be required for a 30 minute track session. Any guesses on what percentage of track time will be spent above 10 psi?

I would also still like to know the effects of low water level on the transient flow response of a mechanical water injection system though.

So last night I sent another member payment for a AIS 3gal tank and aquatec 250psi pump for $150....so now I'm committed to mounting it behind my seat. The rest of the kit I am going to piece together either from AIS or Devil's Own. Here is a picture of the tank...the pump gets mounted inside/below it.

http://www.alcoholinjectionsystems.c..._over_view.jpg

I do have two questions though.

1) At what pressure are the nozzles rated for correct flowrate? The pump will be operating at 200psi through a 22psi check valve making the effective nozzle pressure ~178 psi. If I decided to run two check valves (one for pre-turbo and one for pre-TB), then the nozzle pressure would be ~157 psi.

2) I'm debating between the AIS 22psi check valve and the Devil's Own 16psi check valve. The AIS one is the more conventional style while the Devil's Own is a custom one that they have made for their kits. Anyone have any experience with this 16psi valve?

I'm not worried about the 6psi difference when using one check valve, but if I were to use two, that would add 12 psi to my nozzle pressures over the 22psi check valves.

I use the washer res. And a devils own single stage kit. Been working flawlessly for two years now. Im using straight water

Nice tank!

1) At what pressure are the nozzles rated for correct flowrate? 150psi usually

If I decided to run two check valves (one for pre-turbo and one for pre-TB), then the nozzle pressure would be ~157 psi. use a Tee before the check valves and install one close to each nozzle then both nozzles will receive ~178psi.

Also, I'm working on a calculator that will give corrected nozzle flows given specific system parameters. That's why I'm interested in the pressure that nozzles are rated at.

you can check coolingmist's webpage and they rate their nozzles at different system pressures

It looks like nozzles are actually based on flow at 100psi.

From the AI Nozzle/Jet sticky....

and


Also, after reading this thread it is hard for me to trust coolingmists' numbers as I completely agree with Richard L's math.

https://www.rx7club.com/auxiliary-injection-173/indepth-study-wai-injection-systems-820079/