I usually read just the premise and conclusion of Howard's posts. The middle part makes my head hurt. That's what we value with Howard though. His head hurts, so yours doesn't have to. Maybe that's the tagline for your new company.

I may look into AI for the track.

 

First, kudos to Howard Coleman for presenting the engineering & scientific reasons for ai!
THANK YOU. As Howard mentioned, some very bright engineers (at GM) developed a system in the 60's for turbo engines, but the general public would not accept adding water/alcohol, at fill ups. I'm a retired engineer, and very much appreciate this summary & advice.

In 2008, I bought a single turbo T04R, no emissions hardware, PFC, V mount, ~400 whp car. I added Rice Racing's pre-turbo ai after researching various systems. I sold that car for several reasons (I did not do the original build, no AC, title issues, etc etc).

In 2009 I purchased a twin turbo FD (full sequential, with emissions hardware, 99 spec twins, with PFS engine rebuild smic/midpipe/cai).

I like the streetability of this package ( better low end torque than my former car). Coincidentally, this car is at about 300 hp as shown in Howard's example.

I knew I wanted an ai system (water only) for this car, mainly for reliability (steam cleaning, knock resistance).

But which system to install?

I liked the Rice Racing setup very much (pre-turbo, 10-40 micron fine droplet atomization, tremendous hp potential). However, I was worried about this system on a twin turbo (water dropout in the intake tubes / possible turbo impeller wear, unequal distribution, etc).

I debated 7 different ideas for this car.

1) pre-turbo as the Rice system, but modified for the twin turbo (development needed)
2) post intercooler using my air pump (smog pump) and solenoids as an air source to atomize the water with air atomizing nozzle (the smog pump has enough cfm and pressure to operate an air atomizing nozzle post turbo another full development project).
3) individual port injection (best distribution, but added complexity)
4) No ai, just periodic "steam cleaning" by drawing in water from a bottle (Pineapple/D Jerome, etc)
5) a simple single injector at the the throttle body
6) a simple single injector directly after the smic
7) Do nothing since I'm running stock boost

(aside: drag racers use "smog" pumps to evacuate the crankcase, to create more hp, less windage loss. Off topic, but I don't think this has been discussed much for rotaries).

I settled on option 5.
A simple Devils Own water injection kit (150 psi pump)and a single ~200 or 300 cc/min nozzle at the throttle body inlet (installed at "430" best location for cylinder/cylinder distribution?? tbd)

 

You should definitely look at AI for the track as a added buffer.

I don't believe your even 9yrs old Rich!

~S~

 

Howard, always a pleasure reading your write-ups, this is definitely on my upgrades list!

 

I am waiting to see a simply way of installing a meth kit pre turbo for sequential twins. I know some have done manual injection, and another member is working on it too. Unfortunately his is becoming complicated for me

 

"Unfortunately this is becoming complicated for me "

that's a very fair comment...

i am confused though since you list AEM WI amongst your mods. i assume it isn't yet installed and you are noodling on what might be the best setup?

one of the central points i tried to make in this thread was it can be really simple. since water isn't a fuel the amount injected doesn't have to be as closely managed as methanol.

i run a HD FJO AI system at 100% methanol and since it is fuel it must be exact at all points on the map.

w water you don't have the problem.



not too long ago we didn't have the problem of too many options. most went to Home Depot and assembled the componentry ourselves.

xbl6z1 is running a setup that would work well for most in this thread... many of the systems are detailed in the AI section. here's a list of a few you could consider.

Alkycontrol
Aquamist
Coolingmist
Devil's Own
FJO
SnowPerformance

anyone of the above would work well. Coolingmist has been a vendor on our board and has probably the most systems installed on FDs. they have a wide range of systems. i have had direct experience w their products and am comfortable with them.

snowperformance may be the largest saleswise in the industry and has excellent products.

Aquamist has especially high quality systems and has been helpful on our board.

FJO offers HD systems which use injectors rather than nozzles and is especially suited for methanol but also works very well w water.

DevilsOwn has an excellent down the middle of the bowling alley product.

pick one and get busy steam cleaning.

oh, Double J, you don't want to be injecting meth preturbo. blowing up your intercooler et al would make a mess of your engine compartment further, the cooling BTUs of methanol would be absorbed by the intercooler which would flip from being a heat extractor to a cooling absorber for a net loss. meth needs to be injected at a different point than water to max effectiveness.

hc

 

Wouldn't the methanol ignite if injected pre-turbo?

 

howard what do you think of AEM WI?

my car will be daily driven.. sometimes tracked.. pretty much every upgrade possible outside of a single turbo and water injection.. single is coming next year... for now i want the water injection. i want go with aem because i am sponsored by a performance shop around here and they have access to AEM products.

 

Right now my setup is 50/50 in the elbow. I want to change it to just water pre turbo. If I was running single I would just move the nozzle pre turbo.

My issue comes from trying to figure out how to run pre turbo with sequential twins (BNR). As I mentioned one guy is pinning his pfc ( that sounds risky to me. I don't trust myself ).

Is there a simple way that I am missing here?

 

in the cold side of the turbo..

 

I have the AEM system and I am very pleased with it. Do your research and I think you'll find it will do everything you need it to do. I also did a write up on the install if you care to read it.

https://www.rx7club.com/auxiliary-injection-173/aem-water-injection-install-write-up-883642/

 

Great idea! How much air can you send with the air pump?

Don't know about RR system, but from what I gathered similar nozzles need a quite high air/water ratio to achieve fog-type atomization. http://www.everloy-spray-nozzles.com...xternal03.html

Regarding the SUE18A nozzle, with Spraying System. SS does not publish similar data correlating droplet size and air/water flow ratio. But I had an exchange of emails with them, and they indicated that I should expect "only" 80 - 90 microns based on the flow resulting from delta pressure between compressor and intake. I guess because of the resulting intrinsically limited air/water ratio. Flowing more air by using an air pump could therefore result in better atomization.

An additional benefit is that you would avoid any O2 dilution of the intake air, resulting from any phase change occurring upstream.

 

Can the use of AI completely supplant air-to-air intercooling on a stock turbo car?

 

I'm planning to run WI system...

I'm no expert in WI, but I do wonder about the nozzles... Are some better than others?? or Are they all the same. I ask this because I want something that will atomize well under pressure.

Also,.. this might be a stupid question.. but has anyone blew their engine when it was raining outside?

 

I found that the Bete PJ impingement nozzles atomize well with a 150 psi pump

https://www.rx7club.com/showpost.php...1&postcount=47
https://www.rx7club.com/showpost.php...6&postcount=14

- Sandro

 

Thanks Howard. This is a good thread for me. I just got started in this game, and I'm all stock other than a AST for now. (Planning on a DP, cat back, emissions elimination, cheap bas intake, and maybe a small SMIC with piping)

Someone correct me if I'm wrong, but if I'm understanding right, you can put AI on my car without having to change or adjust anything else, and it will make it more reliable by decreasing temps, keeping internals clean, and stopping predetonation.

So here's my question. Why would anyone not put this on? What's the downside? There is an upside and downside for everything. What am I missing?



Sorry, I know I'm a nubbie. I'm just trying to learn from all of you guys.

 

"what do you think of AEM WI?"

i personally haven't had experience w the AEM system but know a number of people that are happy with it.

as you may have seen adamrs80 (post 36) is happy w his... "I have the AEM system and I am very pleased with it."

Adamrs80 has an excellent thread re the install of his AEM system so do check it out...

https://www.rx7club.com/showthread.php?t=883642

"Can the use of AI completely supplant air-to-air intercooling on a stock turbo car?"

yes you can but it is worth noting that an IC is working all the time taking heat out of your motor which is a plus. in addition, while the water does a great job why not obtain even more cooling using the IC. IC do a great job removing heat... at top boost air from the turbo is often at 300 F and the IC removes 130 degrees from the charge air. the more cooling the better.

"if I'm understanding right, you can put AI on my car without having to change or adjust anything else, and it will make it more reliable by decreasing temps, keeping internals clean, and stopping predetonation."

yup.

"Why would anyone not put this on? What's the downside?"

many people still don't understand the benefits of AI. as long as you don't "tune up" (raise boost--lean out motor) there is no downside other than hardware, install cost and your work keeping it filled. (many kits have a low level LED)

"I do wonder about the nozzles... Are some better than others?? or Are they all the same."

most nozzles are similar. IMO the differences from nozzles are not significant when viewed empirically. the micron size of the droplets isn't too important because the water does not function significantly until it reaches the combustion chamber where it vaporizes. i do suggest a 150 or 250 psi pump but other than that... just get it in your engine. i like the elbow or the silicone coupler as a location for the nozzle(s).

keep it simple

howard

 

Thanks for the info Sandros.

What I would like to see is how it atomize under pressure.. Has anyone maybe use clear pressure chamber and see how these nozzles atomize under say 16lbs of pressure?? I ask this question because one engine I bought the guy ran WI, no filter, and tap water. I could see the lime build up and how the water didn't atomize and ran down sides of the intake manifold.

 

I doubt you can find pictures under those conditions.

But in my opinion it should not change much if you are using a high pressure pump.
What counts is the delta pressure across the nozzle.

You may want to confirm this with Bete directly. They have good technical people you can talk with, or send them an email with your questions.

- Sandro

 

Comment on nozzle spray characteristics:
I just installed the Devil's Own kit and tested the nozzle (150 psi pump, nozzle at atmospheric). I'm happy, it's a very fine mist/fog.

FYI, their nozzle is a simple orifice like other kits.

However, the nozzle holder has a couple neat features:
1) surface mount, does not restrict intake air flow, and
2) machined cavity at the nozzle holder exit, creates a mixing chamber, to help atomization.

Sandro, thanks for the comment.

Air pump (smog pump) characteristics:
1) FYI, these pumps are "positive displacement pumps" ie they flow the same volume regardless of delta pressure (inlet to outlet)
2) cfm flow is proportional to rpm (not delta pressure)
3) The smog pump cfm is high enough to create a very fine spray, if using an air atomizing nozzle. Higher cfm= finer water particle size
4) Although I don't have data for the rx7 pump, I think it would be similar to the pump shown in this link, see graph "Vacuuum Pump Airflow Comparison" in the link it has CFM vs RPM,,,,,,,,
http://www.dragstuff.com/techarticles/vacuum-pumps.html

 

I did, but it was rain colder than 32 degrees.

I dont think snow injection is as effective as WI. From personal results lol

 

Very interesting, thanks.

For comparison and further background, these are links i found regarding a Japanese atomizing nozzle manufacturer, with comprehensive technical data. As you said, the higher the air cfm, the smaller the water droplet will be.

http://www.everloy-spray-nozzles.com...xternal03.html
http://www.everloy-spray-nozzles.com...nternal08.html

- Sandro

 

Keep up the great work Howard, most of use appreciate it.

 

Howard - excellent!! For the other readers: The "cooling" is really the latent heat of vaporization of the fluid. Simply put it is it's capability to absorb or release heat when changing state (in this case liquid to gas absorbs energy). Ever seen a carburated intake manifold completly iced up?

The only fly in the ointment with your calcs is gasoline is now about 10% ethanol which has about 2300 BTU/GAL. This mixture if at 10% is about 1085 BTU/GAL.

Regardless, water injection can have some very beneficial effects. BTW they were injecting water in aircraft engines in WWII. As far as injection, water by far has the best latent heat compared to alcohol. So I would only mix alcolol in water to prevent the storage tank from freezing in the winter months. We used to simply use windshield washer fluid.....

Tom

 

"Why would anyone not put this on? What's the downside?"

Coming from someone whos been in the rotary world for about 4 years,has stock ORIGINAL turbos and engine pushing ~330whp at 13 psi; tracks and drives on streets, I would like to give my reasons for hesitations towrads AI. Perhaps people can reflect on my concerns which most prob is on a lot of non-AI STOCK TWIN owner's minds.

Besides the obvious small possible concerns/issues [budget, instalment (who/were to install), adding more possible complexity to a complex car prone to failure, etc]

My biggest issue or concern is deciding what to do with, and how to set it up correctly to meet that goal.

Personally, I dont see the point of adding AI to my stock motor and then tuning for 15+ psi on stock twins. I would want to add AI and then set it up to work with my current setup. This means I wil still run 13-14psi at ~11.0 AFR and just have AI on top of that just as insurance. Heck I love telling people im on my original motor when they come up to me asking how many times ive rebuilt. My motor still pulls great vaccum and I def wouldnt mind keeping it this way for awhile untill I am financially stable enough to rebuild.

-So my concern(s) are/was this. (some have been answered). Can I run AI and just not tune for it? (Ive learned the answer is yes) .....ok so,
-How will I set up my AI to do that? Do I use different nozzles? program the system a different ways not to inject too much AI because I do know that I will loose power as a result.
-So if I dont tune for it, how much hp am I sacrificing?
-So overall is it worth it? **** my turbos arnt even gonna last that much longer and when they do blow Im going to go single or bnr (assuming most people will go this route). Then I will really look into AI. Even then I wil prob not concider tuning for AI, just adding as insurance.
My setup has been pretty damn reliable thus far. Im tuned concervatively at 10.8, ive got a V-mount, I premix, maintane,etc So why add something quite expensive to an already pretty reliable and conservative setup which may decrease power and possibly not add much logetivety?

Answering these questions will prob fix my undecisiveness. Thanks