he howard, how are ya!!!

>>currently i am near 88% maxxed out on my 850/1600 injectors at 14 psi boost.

this seems odd to me as the numbers dont match and I can relate as my car is seeing the same behavior that im trying to debug, ..... what i mean is that according to my understanding and max's calc page ( http://maxcooper.com/rx7/how-to/fuel_system/calcs.html )...you should be making like 520+ rwhp at 88% with your 850/1600 injectors. Im guessing this is not the case at 14 psi. My track car is behaving the same way, injectors are close to max when i get to 14-15 psi, yet they should be at maybe 60% as my 750/1600 setup should support way more. I believe there is somthing wrong in the inj setup, either the inj lag setting or resistors or somthing. I decided to try a low-imp injector driver to replace the resistors to rule them out, then ill check the lag settings.

anyway, I would get those numbers correct first, as 88% at 14 psi is not right, unless you are making 520rwhp at 14psi!!! :-)

 

this thread is proceeding valuably along and is not about my injector duty cycles. i mentioned them while in the process of making the point that WI can fascilitate the reduction of fuel (18%) into the motor allowing the duty cycle to be decreased.

i run two 44 lb/minute ( 2 X 44= 88) turbos and they make maximum airflow at 17 psi on pump gas. comparatively a GT4294 makes 85 lb/minute at 23 psi. your R85 makes 56 lb/minute at 15 psi and you should be at 70% idc making 415 rwhp. you could turn up the boost to 33 psi and make 64 lb/min.... i wonder if the motor would make it to turn 5

draw your own conclusions on my duty cycle but please don't compare my setup w a single.

let's get back to WI.

howard coleman

 

sorry

 

my sincere apologies to a great guy and fellow rotary roadracer if it appeared directed towards you rather than the issues you raised.

you were very correct to make the comments you did if i was running a single. my twins just have different metrics.

sorry 2

 

i had the same ideas about where to run the water injection nozzles. i thought moving them closer to the engine might help out a good bit, but then i realized that the IAT sensor wouldnt be able to read the "effect" of the WI and the correction would be bunk at that point. i wanted to be able to SEE what the difference was. i may be wrong in assuming that this correction value is something worthwhile, but it just seemed like the right thing to do. i have my nozzles in the greddy elbow using the fuel injector bungs. though, they are relocated. ill take pictures later today and see if i can post them up.

 

are you logging IAT? if so is there a measurable temp change when your WI is on?

i plan to continue to use my relocated (IC to elbow tube) IAT to plant my fuel map where it should be given general ambient temperatures but will tune using AFRs and EGTs under boost.

i do think that a significant part of the cooling gets lost heating the Greddy aluminum elbow, throttle body, UIM & LIM manifolding when injecting upstream.

i want all my cooling in the combustion chamber and therefore plan to locate a jet in each of the 4 runners in the LIM.

howard coleman

 

thanks howard :-) ...ok, back to water injection!! ;-)

 

I do log IAT's (GM sensor) and after tuning without WI, I was seeing temps up to 179F at 17psi, 7500 rpms. Ambient temp was in the mid 70's at night.

the next day after adding fresh air ducting to the intake filter and turning on WI, ambient temp in the 90's, I was only seeing temps in the low 130's.

Of course tuning, I was making a pull every 5-10 minutes. I do use a rather small SMIC. I use the stock elbow, so I'm not losing cooling there. And I don't have data with fresh air ducting and no WI available at this time. (sidenote: I did take the heat shield out and left the ducting in place...fresh air mixed with hot radiator exhaust...and was able to notice a loss of "pull"...so for the folks that say before turbo intake temps are not crucial, I beg to differ. (not you Howard...I know you are equipped)

you can see my WI line just before the elbow.



Howard if you don't mind me asking, did you switch from internal WG's to External? if so, to get some backpressure down???

 

during tuning they were logged via BDC. we opened them on spreadsheet and noticed that they immediately dropped to 17C and stayed there. . . it was cold outside and i dont remember ambiant. one thing i do wish to do is some cold air ducting for the turbo and a thermal blanket for the hotside. im more afraid that (and i assume you feel the same way judging your posts) the cooling effect is somewhat lost by the time it all gets to the combustion chamber. thats the reasoning for a thermal blanket. . . although my exhaust manifold and turbine housing are ceramic coated, im sure it does SOMETHING to the LIM.

so, are you speaking of putting the nozzles in the LIM at the port? pointing directly at them? as in, right at the bend in the runner sitting parallel to the ground? i think that might be a very beneficial place to have them if the spacing and heat doesnt take its toll.

 

my plan is to locate a jet in each runner of the LIM. the jets, probably Aquamist, will point 90 degrees to the flow direction. while jet direction/flow is conjectural i like the 90 degree position. the jets will locate on the inner, or toward the center, of the engine side of the LIM somewhere near my secondary rail.... the rail or log, not the injectors. i plan to fab a 1 into 4 stainless steel log manifold that will bolt up to the jets. i will coat it/cover it w insulation. since there is some sort of double wall structure near the rear 2 ports, i don't remember what it was but it is but it is gone, i will have to do a bit of machining to get to the two rear runners.

howard coleman

 

I'm very interested in hearing more information about this as I'm seriously considering doing some sort of WI system, whether it be 1-step or 2-step or something 3D based on load vs. RPM...

B

 

YAYYYY BDC!!!!! finally you're going to give it a shot!

 

Ok I had the car in the air today doing an oil change. Here are some pics of my WI set-up. I tried to use the paint feature to label each picture but for some reason it's saving in black and white. In the second pic the orange led on the bottom left is for "system on". The orange led on the right is for "pump operation". It kicks on and off with it's internal pressure relay and fully pressurizes the system to 100psi and then shuts off automatically. I put my solenoids red leds on the boost gauge itself because I could easily see the correct boost pressure they come on and not have to look in another location of the indicator light. One is at 2psi and the other at 8psi.

 

Here are a couple pics of the solenoids. There hard to see but to can clearly see the "T" fitting in the first pic separating the hard line. They are mounted just below the steering arm and on top of the subframe(low enough so there's no heat problems). Also, I didn't get any pics of both my Hobbs pressure switches because they are mounted underneith the dead pedel inside the car. This keeps them out of the eliments.

 

DAMN! not so subtle.

 

if it hadnt been raining, id have pictures of mine up. hopefully, this weekend.

 

this has been a pretty decent thread on WI and w 650 hits to date it appears there is solid interest, and of course there should be.

i think it would be really helpful to start a new thread which should track on similar lines to the Aquamist forum sector entitled, "Disaster Avoidance."

i won't be able to start on it until this sunday but my concept will be to set forth why we should TUNE for WI, discuss each component of a proper system, and then get to the meat of the thread..... specific system failure areas and our options to defeat each.

so all you WI fans get your thinking caps on and lets put together THE thread on bulletproof FD WI. of course if anyone wants to start it before i do feel free.

probable title so as to be Search friendly: "Water injection... system failure avoidance."
or whatever you can come up w.

howard coleman

 

I must agree. I would have to say this is one of the best threads that I have read to date. I would have to say that it comes second to another though. I can't recall the name of the thread off hand but it went in an talked about WI in the 7. It briefly mentioned location and ther was a short argument. This thread is quite a bit more informative as to where you should place the injectors. And since there is not really good thread to date on this I highly encourage you to take it to the next step.

Also I must say that people that have already installed the system sonderful jobs. But let's not stop there, show us what you have.

Thanks,
Z

 

I've had this installed - PiNZ VapourJet System 2 (Mapped by Haltech E6X), which injects into the elbow.

Haven't given mine a beating yet (freshly rebuilt - I'm just dying to mash the accellerator!), but I know others down here in NZ who swear by them Temps dramatically dropped (only a few degrees above ambient!) and failover measures give a certain amount of confidence if you forget to fill the reservoir or there's a problem

Will get some logs online once I've got a few more kms on my engine (or if I can extract some from PiNZ)

 

I don't follow you? If your talking about the protrusion of the WI nozzle and the air temp sensor resticting flow, it doesn't. Only when the system is activated will I loose .5 psi because of the water spraying against the air flow for better atomization. That's no bid deal to me.

 

I forgot to add my "system failure avoidance" info with my pics. My gauge on the right side of the Mickey Mouse ears has a Nordskog Digital Fuel pressure gauge. Because my system is under full time pressure, I can mount a fuel pressure regulator in-line to monitor the water pressure with that gauge. The great thing is that my Nordskog gauge has an adjustable fuel pressure warning feature that flashes the display as well as it's own electrical lead that it sends a ground too to activate another device. What I was going to do was use the lead from the gauge to open another solenoid and use it as an electronic blow off valve. So in the event you loose water pressure in a set-up that's tuned for WI, my gauge can send a signal out to and open the solenoid that's connected to the TB elbow and vent boost pressure. Example: gauge sees 40psi and sends a signal out to open the solenoid (blow off valve) well before the system reachs 0 psi. No boost means no boom. This would also keep the engine from reaching full boost if you run out of water due to the solenoid (blow off valve) being constantly open under the preset water psi warning level. Oh yea, my set-up has been working reliably on my Fd for over a year.

 

My system on my Fc.
Coolingmist single stage. I have two LED's one tells me that pump is running and the other is a "clogged Nozzle" indicator I have it adjusted so it lights up breifly and goes out. If the nozzle is clogged it will stay lit for a period. Pump and tank and all controlls except boost pressure switch is in the drivers bin.

I also have air temp guage with two senders I can read on both sides of the I/C with a flick of a switch. I can watch the temp drop as I'm under boost/ spraying water. I also chill my water/ mix via a cool can under the hood. My nozzle is located away from the TB close to the I/C as coolingmist recommends

Johny

 

The rest of the car for interested parties

 

the ideal failure avoidance...doesn't light up LEDS if something fails, it takes action.

I believe the "action" of an electronic BOV (some might call Charge Relief) has some flaws.

1) WOT, venting charge (dropping boost) will trick the boost controller and could damage a turbo due to over revving. Differential Equations says, once your charge relief valve is flowing its maximum pressure, the turbo (if strong enough) will then again begin to increase manifold pressure. Now, with no water to cool that extremely overheated charge, on that aggressive tune...my bet is on KaBoom.

I'm not following the above statement, the pump and accumulator will in a way regulate the pressure...are you going to install a regulator (usually requires a return line to "regulate") just to monitor pressure in the cabin so the gauge can open the electronic BOV??

and don't like the example given.

If you tune with 100psi of water mixed with fuel, and the system waits to "protect" at 40psi (or any other significant drop), on an agressive tune, again my bet is on KaBoom. Water pressure will determine the flow rate of the nozzles. The only line that is under pressure the entire time would be the line leading up to the solenoid. So if the pressure drops in that line...the reservoir is empty, a high pressure line has become detached, the pump has failed, or accumulator is failing to hold pressure. In some cases the result will be the pump running dry, endlessly. Now, at any throttle position you are either venting air (after IC) or your engine is breathing un-filter air.

Howard has a great idea to lay all these cases out and then brain storm how to bulletproof each case. IMO, the "Water injection... system failure avoidance" thread should be extremely structured and as little discussion as possible...maybe edited down, once a case has been discussed from all angles. This thread has gotten way off track from the thread title. But I think Howard is set on what he wants to build now.

 

Guys,

Did we ever uncover any definitive answer about the optimum location to inject??

I have not spent time on the WI forum to see if there is a universally accepted optimum location so Howard or someone else please chime in and let us know what if anything was learned.