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Auxiliary InjectionThe place to discuss topics of water injection, alky/meth injection, mixing water/alky and all of the various systems and tuning methods for it. Aux Injection is a great way to have a reliable high power rotary.
I apologize ahead of time for the broken record to be played. I just wanted to verify and clear up a few things before I go shooting another type of fuel and water into my car.
I want a very simple boost activated progressive, post ic setup. (Would love pre turbo, but I am skeeeerd for my blades) I am looking at AEM and not sure about nozzle size yet. She has
1. Mild street port and pretty much all bolt on mods.
2. PFC cleaned up a bit. AFRs are pretty normal for what the avg. I see on this forum. I am not running an O2 sensor. My wideband sensor took its place.
3. Running 10psi stock sequential twins on manual controller. Once I have the inj up and running I would like to crank her up to 12-13psi. My current injector duties are around 76-78% wot. Occasionally bumping 80%. Stock injectors.
4. I mix minimum 30% minimum 96 with 93 octane and premix.
Ultimate goal is to increase power a bit via boost and lower temps without changing out the fuel injectors just yet and obviously not blowing her up via detonation. I have much more to learn!
My first round of questions.
1. Pre BOV. I have read it doesnt matter and I've read no way. I would think running it right after the bov wouldn't be much different than running it all the way back on the charge pipe. Looking at the pic does it appear I have enough room after the bov for proper atomization? Like enough for the meth to actually have time to cool the charge air temp? From what I gather it doesnt make much of a difference with the water.
2. Running 50/50. If I was to take an avg of what I read I should not have to worry about tuning. The meth should semi negate the affects the water has. Is this a car to car basis kind of thing? Sound accurate?
3. With second question in mind will a 50/50 mix on avg possibly help with the injector duty? I guess that would depend a lot flow rate obviously, but would the water totally counter act the meth, or would the meth still help a bit on the duty being that it is a fuel. Apologies again for the redundancy of these questions. Regardless what I read I prefer to ask and still hear an answer for something like this.
4. With said pic where would you mount the injector?
I am sure I will have more questions to come.
This will probably be one of those mods I should have
done first.
No one in this section? Man I am a few years too late on this lol.
I am getting ready to install an RX7Store resonated midpipe and would really like to get this water/meth inj going.
Any fuel mixed in the AI will help keep lambda down, with enough water provided you can stay below 0.85 and control temps it doesn't matter either way excess fuel or water is there to stabilise combustion and temperatures. If you are going down this path I would suggest gapped fine wire irridium spark plugs, if you get any evidence of hesitation in the top end after that upgrade ignition.
i can't really see the point of that bov, I wouldn't run it myself. For the AI ratio you will likely run even if you are leaning on the factory fuel system it shouldn't present a hazard anyway.
Thx Slides. I knew someone would help me!
I have a twin power. Not sure if that will help or not for an upgraded ignition. Some say it will.
For the bov I was/am under the impression that it actually has a purpose besides making noise. A bit of protection for the compressors. I cant really say myself because I do not know the system well enough. I should say I am still new to the forced induction all together so still learning. I see quite a few people running without them. If it is just for noise and no protection I have no issue taking it off. If it offers a little protection I would prefer to keep it on.
As for the ratio I am not sure yet. I understand that a 50/50 is awesome. As for volume (nozzle size) I am still researching. I definitely will not "tune" with this. I just want some added protection, some steam cleaning, and if it happens to help inj duty that would be a very big plus. For the progressive on and off I am sure I will have to play around with it. Probably on at 7psi and max at 12psi, but again I assume that is vehicle specific. Thanks for your help!!
Lol, I just started reading past threads about BOVs. It is funny and a good example of why I am still asking questions after reading many threads on this injection stuff or anything else for that matter.. So many varying opinions. I would prefer to keep the bov. If there Is no way it would work with it there I will definitely consider getting a new elbow without one.
Testrun,
A BOV is necessary for longevity of the system and turbos.You can run without it but this will stress everything over time. Not a good idea. Where your BOV is fine. Mine is in the pipe between the IC and the elbow. As for the water-meth, I would first replace your secondary injectors and secondary fuel rail. You are at almost 90% duty cycle and are at 11 psi. You have no headroom to go higher boost. You will blow up your engine since you will exceed your necessary fuel delivery from your injectors and will run lean and your engine will go bye bye even with WMI. As for the WMI, I would put a nozzle right after the BOV in the elbow, as far away from the throttle body as possible as to increase dispersion and mixing of the spray with the incoming air.
Mike
Damnit. I was trying to avoid injectors lol. She runs so smooth and strong now. I see injectors opening up a can of worms. I haven't researched it too much, but I am not interested in 1600s as I hear hesitation is an issue. I am concerned about 1300 (bored out 850s) for reliability issues. I guess you are correct if I want to stay on the safe side, although many have said I am ok up too 12-13psi as long as my afr are ok. I have read that 80% is about max you want to see and then many of the pros have said hitting 100% isnt going to kill you or it if afr are ok.
I could be totally safe. Stay where I am at with the boost. Add the water meth and change my damn gearing from the 390 to a 430 (did auto to manual swap and never changed rear) Get my added acceleration there first and then go from there. I know myself well enough to know that I will want more.
Hey Tom!! Yes I am running the factory bov also. After all the thought of messing with the fuel I think I will stay where I am at for now. I am still 10-10.5 when at 11psi. I think it is 10.5 I will have to check.
I am sure I could squeeze 12 psi out with no issues, but she runs strong as is. I may try to add this resonated midpipe. If she creeps I will just switch back and keep her for the future.
I think I will add my water/meth and work on my 4.30 and kaaz lsd. Finish up the stereo, and exterior and enjoy the car. Once it is rebuild time I will mess with injectors as I will probably go bnr III. Hopefully not for a long time lol.
So move the bov back to the cold air pipe (if I want to keep it) and inject at the beginning of elbow?
I was looking at sakebombs aem set. I haven't checked rx7store yet. Again, I just want a simple setup.
Testrun,
Be careful with the mid-pipe. Once you get rid of the cat and the restriction of the mid-pipe, you probably will boost creep. Once you boost creep, you don't have the fuel capacity to overcome the lean situation you may cause and then again boom! Sorry to be a Debbie downer. Just trying to save you a big dollar engine rebuild. Been there, done that twice myself. The injector change is relatively easy. I have stock RC tuned 550cc primaries. My secondary fuel rail is the RP original one. At first, I had Bosch EV14 2200cc secondaries which worked well and now I have 2200cc ID's. Enough fuel for any twin setup. Still stock fuel lines and damper. One days work and all fixed.
Mike
Mike I really appreciate your input. I would rather be safe then sorry. Like everything else, many say it will creep others say with the rb dual tip it wont. Not the magnaflow resonated anyway. I may have to try it out and just be safe. It may not even be worth the hassle right now. If it isnt giving another 20+hp it probably isnt worth it with the noise and all.
As for the water/meth I see the o negative. Unless it will get me too rich and cost me power.
I run the newer AEM water injection system and like it. There may be others as good or better, but the AEM unit works for me. I installed my injector about 9" before my Greddy elbow
And you should port your stock wastegate if you are modifying your intake and exhaust. I hold a steady 12 psi with a ported wastegate and free flowing intake and exhaust
She holds great now with the manual controller. I have 0 creep with the 3"dp, hi flow, and rb dual. She will hit 10.8-11.3psi (depending on ambient) and just hold it. No idea what it will do with the dp. The pettit hi flow I currently have on probably 300 miles on it so I am in no need to change anything. Just got a good deal on the mp. Always looking for more hp and less heat so as long as it doesn't lessen the reliability.
I may just take your advice and plug the bov. You using an m5 nozzle?? I dont recall on your build thread. I know your using the windshield reservoir.
I didn't know you have two BOV's. You can get rid of one. Just pull the vacuum line from the aftermarket one and plug it closed. The aftermarket BOV will just stay closed then.
Mike
I suspected you still had all the factory intake stuff. The aftermarket bov may not stay closed like that depending on the spring seat pressure, either replace it with a blanking plate on the elbow or feed a pre-throttle boost reference to it so it stays closed on boost.
I have high flowed secondaries, a "300l/h" 044 silhouette pump fed from an under car surge, auto exe intake, twin pass intercooler, 3 inch dump and 3.5inch exhaust with a 6 inch body low cell count catylist. I am maxing out the stock turbo/gate actuators seeing something like 16 psi at mid-high 80s duty cycle. Works well enough but i'm sure modern bosch ev14 based injectors would be a better thing. I'm going to do the "wrong thing" and chuck a pair of factory secondaries into a modified primary rail when I go single too, but it's not my every day car so although i will try to optimize fuel consumption on cruise later on it doesn't bother me too much if its not perfect. I will run a pre-turbo air atomiser setup, i think i will stage a couple of solenoids to it with in line restrictors driven from a hobbs switch and the fsctory secondary control outputs.
Lol Slides that's all way over my head.
Only thing I know is I hit 90% duty @7500rpm last night when I took her for a spin. It is getting "cooler" on SoFL the last few days. I really dont know how the whole process works with the PFC regulating the fuel with the temps. I am still learning that.
My AFRs were (from a video I slowed down)
6psi 12.5
7psi 12
7.2psi 10.8 @
10.6psi 11-11.3
11psi 10.8-11.0
11.3 psi is a quick spike and she just holds 10.6psi solid after that till redline.
seems like it was a bit richer last time I checked everything, but it was also warmer. Like richer by .5
So after last night I am reconsidering injectors again lol. My main go to guy is telling me just get a set of bored 850s and he said he could slap a map in with the new injectors for me. If I get 1300s then I will be forced to run at least 13psi
Air is denser eith lower temps, the ecu compensates for this, which is why your injector duty was higher. If you are sticking with factory turbos or a small single high flowed secondaries isn't a terrible option.
Thx Slides. I was thinking that a lot of my heavier "loaded" driving will be up north where it is cooler so looks like I will just have to get the injectors done.
As for the bov. I think I will move it to the cold pipe and plate the bov on elbow. Hell, I may use the plate for the injection nozzle. I looked at flow rates, but I need to match up what nozzle for the flow. I think it was an M5. I will start with a 50/50 mix and drop down if needed. I know I will run a minimum of 2-2.5 gallons. I was thinking Euro "hidden" tank, but it seems like a lot of $$. I am not that worried about it being stealth so I may just stick a tank in the back. I will probably mount the pump in the spare tire well on a board and keep the carpet over it for some sound deadening. I have no idea how loud these pumps are. Then just run it up to the front. The controller will probably just be mounted on the left side of tunnel in front. Sound like a plan??
Testrun,
Your AFR's look good for now. That will change if you increase boost, it gets cooler outside or both and you will run out of fuel. IMO fuel delivery is more important than anything else. If you lean out your engine enough, it will blow up. Piston engines are much more forgiving in our HP range. The bored 850cc's, bored to 1300cc, are OK but are known to stick open, outright fail, and are not modern technology. The Bosch 2200 EV14 are only around $175 apiece, still much cheaper than 2000ccID's. You can get the whole setup with new secondary fuel rail for around $500 from Rotary Performance. Do this first and worry about the other stuff later, if not $500 may seem super cheap as compared to a $5000 to $8000 for a rebuilt or new engine.
Mike
"Your AFR's look good for now. That will change if you increase boost, it gets cooler outside or both and you will run out of fuel. IMO fuel delivery is more important than anything else. If you lean out your engine enough, it will blow up. Piston engines are much more forgiving in our HP range. The bored 850cc's, bored to 1300cc, are OK but are known to stick open, outright fail, and are not modern technology. The Bosch 2200 EV14 are only around $175 apiece, still much cheaper than 2000ccID's. You can get the whole setup with new secondary fuel rail for around $500 from Rotary Performance. Do this first and worry about the other stuff later, if not $500 may seem super cheap as compared to a $5000 to $8000 for a rebuilt or new engine."
totally agree w the above.
boost creep was mentioned... i will add mod creep. news flash, it never ends.
you need a proper amount of fuel and you also need AI. i suggest you relocate the BOV from the elbow and locate your AI nozzle to that location. do not rush things or you will blow your motor. do it once, do it right.
Thx Howard. Yes I want to do things right the first time. I also would like to make sure what mods I do supports future mods If possible. Like injectors big enough to support big power, but not big enough to cause me problems with hesitation etc. I want to over build this car. I feel she is fast. I know when I finish her she will be very fast. Hopefully I will have a long way to go for if and when I decide to make her scary fast.
The amount of opinions out there is crazy. Some of the most diehard rotary guys I've known for 20+ years do not run water injection. They truly see no reason to. A few think it is a total waste. All the research I do makes it look like magic. Almost like snake oil. The way I understand combustion chambers it makes total sense to me, especially with the rotary. Fuel injectors next. I will purchase the ai kit I want and then have the rear end rebuild. While diff is out I will probably install the kit and maybe move my fuel filter or at least change it.
Sgtblu I will definitely consider that. Funny thing is I keep thinking it is post ic. I will do some research on it for sure. Thanks for the input.
To clarify, the stock IAT sensor IS post IC. It’s also post t-body under the intake manifold and can heat soak. You might consider a fast reacting wannaspeed (there are others but familiar with his) sensor relocated (to reduce heat soak) to post IC but before the AI nozzle (so the fluid doesn’t mess with your tuning). Fast Reacting IAT sensor for Rx-7 - Wannaspeed
10-26-18, 09:01 PM
