Using a fuel injector as a nozzle
 

I plan to make ~230whp without an intercooler on my 1.6

Obviously i need water injection to keep IATs down. I have decided to inject water only, pre compressor.

Is there anything stopping me from using a fuel injector for flow control? I have heard that water rusts them shut but if i use an EV14 which i believe has stainless internals i should be immune to this?

The plan is to piggyback the water injector from one of the fuel injectors in the rail, which should give me a water flow rate proportional to fuel flow.

<p></p><p>&nbsp;</p><p>Most decent water injection kits inject at a MUCH higher pressure than fuel injectors are designed to handle. Like, triple.&nbsp;</p><p>&nbsp;</p><p>EDIT: That is, triple the max they would be reated for. ~300psi.</p>

Hmm. Reasons? Atomisation?

Surely a fuel injector doesnt have problems atomising fuel, so if i run water through one at, say, 100psi, surely this would do it?

I'd be worried less about pressure (I agree with your reasoning) and more about the long-term effect of a water / methanol mixture on the innards of a fuel injector deigned for petroleum / ethanol blends.

Why not just fit an intercooler.

Fuel is much more volatile than water. Also, you are injecting it further upstream. I would say that you want to do whatever possible to atomize the water as well as you can.

I understand the effects of pre-compressor injection, but Ive seen some evidence that the water can actually damage the thin leading edges of the compressor.

https://www.miataturbo.net/attachmen...ine=1437509151

I dont think its worth it.

Because i'll shit in your mouth.


Compressor damage is still a big worry for me. I remember reading that volvo tried pre comp injection in the 80s and it killed a turbo after 80k miles. Thats a ton of mileage, but knowing volvo thats probably pushing 5psi boost and with tiny amounts of water.

Any more info on that pic?


Did a bit of googling on the EV14, found this PDF. Seems methanol is okay, ish. Water only may be the answer.

Cold piss could be you're answer either.

Normal EV14s do not have all-stainless internals. Let E85 soak in an ID1000 and it will eventually corrode. I shudder to think what a normal OTS EV14 would look like after a few months of pure water.

This is not a good idea.

A boost based WMI kit is about $280...not expensive enough to warrant rigging something up IMO. Run a nozzle post turbo with water or washer fluid and see how your BAT's are. They'll likely be A-OK

I'd keep it simple if I were you. If you plan to only inject water, then inject it post-turbo with a regular old nozzle. Running water through the compressor doesn't help it vaporize because the air (especially in the UK) already contains a lot of water and when you raise the pressure of the air its ability to hold water actually decreases (given constant temperature -- look at psychrometric charts). With the temperature rise through the compressor, it ends up being a wash -- in general, the water stays in small droplets until the combustion event no matter where it is injected.

Alcohol is a different story. That can be injected pre-compressor effectively and a good portion of it will phase-change and absorb intake heat. It also doesn't eat compressor wheels like water. But it's overall capacity to resist det during the combustion event isn't as good as water.

Rest assured that if fuel injectors could be effectively used for this, they would be. Also, I'd be stunned if you can make 230 on a 1.6 without an intercooler. I managed about 190 targeting 10psi -- which is about as far as you can safely push it with water injection/no intercooler. I'm currently fitting an intercooler on my silver car to make things even KISSer.

Injectors | Magneti Marelli

I love it when people overcomplicate things in the name of simplicity

The whole PWM of the pump setup is so simple and proven. I see no problem with it.

OP,
I like your plan to run just water. Let the EMS control fuel, you dont need to add any to your water injection. I would recommend adding a little touch of something to prevent algae bloom though. Like a little splash of alcohol.

Tons of useful, usable advice.

Joe, Brain, Sav, thanks. I am now hunting for an IWP injector, they seem to be OEM fitted to a few renaults and fiats so should be a simple ebay buy. Ive believewater flow rate needs to be between 20-40% of fuel flow rate so ill size my cc/min accordingly.

Im loathed to just have a nozzle with on/off flow. If im going to do this I want to have my water flow perfectly tuned at every RPM and load, not have something that is perfect at 3krpm then gets progressively leaner as rpm/boost rise. You could do this with pump PWM im sure but i only have a microsquirt and im sure as hell im not the one to program those curves into a microcontroller.

Hornetball, full_tilt, ta for the words of wisdom. Nice to know that ill get close to my goals at least. I cant help but think that if i injected pre compressor i could run straight water and have even stonger anti-det protection than water/alky mix. That is my motive for this, i dont see the need for meth/alky if you can stop the turbo heating up the intake air in the first place, rather than trying to cool it down after its been heated. Good shout on keeping things sterilized, maybe a shot of russian standard every once in a blue moon would do it.. :D

I picked up a Aquatec 4l/min 8bar pump and lines yesterday, i suppose i should update my build thread.

You're not getting it. Not in the least. And you're not listening.

Water injection works to suppress detonation in the cylinder. It is a very ineffective intake air coolant -- no matter where you spray it. Doubly so in humid England. You can't phase change if the air is already saturated. That's why it rains so much in jolly old England after all.

Alcohol can cool the intake charge some, especially if sprayed prior to the compressor. But it's a less effective detonation suppressant.

Very old technology that the vendors are happy to misrepresent. The term "chemical intercooling" especially makes me laugh. If you're going off what you're reading on vendor websites, just remember, they want YOUR money.

I've attached some real reading.

Okay. Ill take a bite or 2 out of some humble pie. Thank you, hornetball. Theres tons of conflicting info out there, but those pdf's look like a freaking goldmine. I need to sit down and absorb.

I've done WI on my SC setup (3 stage setup), it was pure water. It sort of works. It does work. But it didn't work as well as I needed it to. I was running very high water/fuel ratios, 30-40% by volume and 20+ PSI Boost on pump gas. I don't run water injection any more.

My suggestion:

1. Install an intercooler
2. Install an intercooler
3. Install an intercooler
4. Consider E85.

Even if it's a tiny intercooler, it will help a lot.

If you do end up running WI, use water/alcohol or water/meth, not just pure water.

Meth (methyl alcohol) is an alcohol. ??

Unless you're talking methamphetamines. But I think those cause detonation rather than suppress it.

Water injection worked well for me with the exception that I wasn't disciplined enough to come off track when my low water light would come on. That's operator error.

Methanol, ethanol, something besides pure water only.

Another thing he keeps ignoring, is that even when you suppress the det, you will still make mediocre power unless you can EFFECTIVELY cool the charge. The cooler the better.
When I ran my FFS on e85, I had no det, but without an intercooler the AIT's would hover over 200F, and no matter what you do, you won't make good power at those AIT's. The air is just too hot/thin. You keep adding timing and the car just stays at the same power level.

<p>Ian/Sparkybean, I can see that you're very determined to run water injection, and I'm not going to try to change your mind. I'm an ignoramus when it comes to water injection.</p><p>This is a genuine question, as I've already learned a lot from reading this thread. I'm not asking you to explain yourself because I doubt you, but because I want to learn from you.</p><p>What is it that makes you want to use water injection rather than an air-to-air intercooler? I perceive that as easier, simpler, and more predictable/proven. There must be some advantage to running WI that I'm missing.</p><p>Genuine post, not troll post.</p>

This is what Vlad is talking about:

Your STI Doesn?t Need an Intercooler, Right? » PERRIN Performance Official Blog

Bottom line, with hot air you just can't get the air molecules into the cylinder.

I'm going out to the garage now to piddle on my new intercooler tubing. I do have a basic CoolingMist system I'll be selling BTW.

I can tell you what I liked about running without an intercooler:

1. Engine cooling. OEM auto radiator. OEM air guide and undertray. Never any cooling issues whatsoever -- even when running AC or going hard on track -- and look where I live. I'll also tell you that engine cooling is my biggest worry now that I'm mounting up a FMIC.

2. Intake piping was gloriously short and simple -- basically followed the OEM routing.

You can see all of this in the silver car build thread. Bottom line, you can safely do this and there are some advantages to it. But big power isn't one of them.

<p>Thanks for sharing.</p><p>That seems to reinforce the idea that the way to go is still a big radiator, traditional intercooler, and a bit of ducting.</p><p>*insert THE MORE YOU KNOW infographic here*</p>
https://derpicdn.net/img/2012/10/15/123636/full.png?

WI can be easier to package, have less throttled volume, possibly weigh less (maybe), and you don't have an intercooler blocking airflow to your radiator or any other heat exchangers up front.

In reality, this sounds fantastic. But in my experience, you need an intercooler and it needs to work well to make the most power safely. If blocking airflow as a big concern (about the only one I mentioned that is actually a legit concern IMO), then do a small intercooler that's tube/fin design.

I'd like to offer another suggestion. Since the speed3s are DI and we cant just pop new injectors in when we run out of fuel, we have to add auxiliary injectors in the charge piping.

What you can essentially do is grab a split second box (or other stand alone fuel injector controller) and wire it in based off MAF voltage, MAP voltage, IDC ... any number of things, and basically just have 5 or 6 injectors total, using the ones in the charge pipes for chemical intercooling. The additional injectors could have their own little boss / rail, and just T off the existing low pressure line coming from the tank. From that point its just a matter of programming the desired IPW from the injectors for your needs. It sounds like a lot of work, but ive made a spreadsheet to calculate the IPW for me based of G/s needed and its really a simple just one and done as far as tuning is concerned. The only tricky part would be determining how much of each to use for proper cylinder distribution / cooling / and proper fueling.

I saw a picture forever ago of a ... pretty sure it was an R34 skyline doing this, but for the life of me i cant find that picture.

Did he just suggest e-cool?

I can't stop laughing:rofl::rofl::rofl::rofl:

Oh this thread is gonna be fun

I'm doing a 5th injector on my setup. Because I need more fuel and it will let me keep my 1K ID injectors mainly, but there are other benefits too.

That is a very patsmx5 thing to do.

:giggle:


Once I priced a set of ID 1300's (900 dollars for four!!!), I about shit myself, then I started looking at other options to get a little more fuel. 5th injector seemed like the cheapest/most decent way to do it, it should come in under 250 dollars and won't affect my idle.

I've tuned several cars with this set up, i can show you plenty of logs with substantial drops in boost temps on both pump gas and E-85, so if dude doesn't want to run an intercooler, i fail to see the real problem here?

Obviously the main solution would be an intercooler, but i feel what i suggested is more easily done, more effective, and safer than the wet compression solution that was initially suggested.

<p>Intercooling is nothing new on a miata. And is easy.</p><p>See here:</p><p>https://www.miataturbo.net/diy-turbo...tercool-83180/</p>

On a direct injection car this is for sure the more-or-less best approach to increase fueling. That's not really what the OP needs, needs cooler air temps.

For his miata, the OP should just install an intercooler. It's cheap, easy, works, and the only "downsides" are trivial. Intercoolers are even cheap, probably no more than a WI kit and they don't run out and have no moving parts.

<p></p><p>This x 1000.</p><p>What happens when you forget to fill the tank and you suddenly blow your engine.</p>

Well typically you nuke a piston when that happens, so you'll experience a loss of power, as well as a large cloud of blue smoke exiting the exhaust. Once, I even managed to blow the dipstick out of its tube about 2". I managed to datalog this last time I did it. :dealwithit:

Right, i wasnt addressing this from a "adding fuel," standpoint, though that is its original purpose. Its very simple calculations to just remove X amount of fuel from a MAF curve, and put it back in with an auxiliary injector and use the cooling as a by product.

Im in no way advocating this as a replacement for an intercooler, i am in favor of him just running an intercooler. I just believe that of the options offered, that this one is the most reliable, with the most controllable results.
The thing about using an injector tapped into the MAF / MAP, whichever, is that it gives you the ability to create an accurate fuel map that is spraying 100% of the time. This cools BATs (boost air temp, is that an acronym yall use here?) 100% of the time, cruising, idle, WOT... and not just wide open like a meth kit does. For the record i'm usually pro methanol, i actually have a methanol kit on my speed3, i just feel in this case you need something more controllable.

Hey, I know . . . let's pull all these electronic gizmos, toss the FMICs in the dumpster and run oversized Holley double pumpers. Intake air temps should be like absolute zero if we do that, right?

Listen dude, the sooner you stop constantly bringing completely irrelevant "knowledge" from other platforms into conversations to make yourself sound smart, and the sooner you learn miata's inside and out and actually start contributing, the sooner people will take you seriously. I can talk about other platforms all day long too, but in the end most of it is worthless and no one will care.

None of us even use maf's with the tuning solutions we have for a miata, or the fueling available. E-cool is idiotic on a car like this where intercooling is easy, cheap, and simple, and where we have plenty of fueling solutions. Suggesting piggyback controllers to someone using a megasquirt already is also silly.

We ridicule e-cool every day because of how archaic it is, you probably don't even know what FFS is and who Tom@ffs is and why we all laugh about it so often, and that's ok, but again: we don't have the silly problems ms3 owners have so why even talk about it?

If OP wants to be stubborn that's totally OK, if he wants to be different for the sake of being different, that's OK too. But we here at MT reserve the right to bust the balls of everyone that does that, until they actually accomplish something worthwhile.

PS: I'm really not picking on you, I'm sure you're smart and tuned some cool cars, but they are nothing like what we're working with here, so it's really not helping folks.

Megasquirt supports staged injectors, not that you'd want to use them. Dealing with the voltage offset on the wideband alone made me nuts, I can't imagine delivering fuel off some tapped in shit like that.

I vote we ban the abbreviation ms3 in relation to a speed3 on this forum, the latter is just a tiny bit longer and I can raed and comprehend fasterer.

I'm pretty sure I've made over 230 a few times, not totally intentional, with my hacked up mess of FMIC that cost less than any name brand WI kit. Complication for simplification is insane, I've given up on that crap.

I disagree with your opinion. My opinion is that the best way to increase fueling on a direct injection car is with an aftermarket ECU and, if necessary, larger injectors. But I'm no engineer.

Back when I used to have carburetors it eCooled the charge so much we used to put the beer on top of the engine coming back from the store. But you had to be careful. With a really big carburetor the beer would sometimes freeze.

Right.

Reading the NACA papers was encouraging, a possible 70% increase in BMEP sounded bloody marvellous until i realised that their test engine was initially knock limited and the IAT's were held constant throughout the whole test. I am looking to lower IATs, knock is not (yet) a concern.

Reading further echo's the comments in this thread; water isnt a great intake charge cooler.

After this i started looking into meth/alky/water mixes, which DO cool the intake charge better than water but these solvents only do an average job (at best) of cooling the intke charge. They also screw up AFR's, are more expensive, require mixing, and generally still have nothing on a good intercooler.

Im not sure why i was so stuck on water injection to be honest. Too much time reading vendor websites and hoping for a magic bullet. I think i was also getting confused between IAT reduction and knock supression. Sure you can supress the knock and advance the timing, but as 18psi put it, I wont get any extra power with all that hot air going into the engine.

SO...

Looks like im getting an intercooler. Ill delve into that thread aidandj, thanks for the head start. Triple J, looks like you need to buy me a curry.

...Is it even worth me hanging onto my water injection setup for my power goals? While tuning for MBT sounds nice im sure i could be conservitive with the timing and run more boost.

Shame, im £250 down from this little excursion.

In my experience, pure WI isn't going to help much. I've read way to many WI papers that say they will. If you run water/meth, then it could help, many have dyno graphs to prove it.

If I could do it over, and had the budget, I'd run dual fuel systems, gasoline for driving, something else for boost (E85 most likely). More weight and complexity, it's obvious, but it's the best of both worlds then.

I don't know who originally said it, but god damn that's one hell of a Patsmx5 thing to do :giggle:

:rofl::rofl::rofl:

I know, I suck at making compromises... I own that.

5 or 6 years ago, I became hugely interested in the old NACA research papers which explored the injection of various liquids into piston engines at various locations. Got a whole 3-ring binder somewhere full of those articles.

Lots of different papers came to various conclusions based on differing methodologies. Some injected liquid directly into the combustion chamber at various timings, some metered liquid into the intake manifold at ratios varying with fuel, some explored the relationship of water-injection to power in the presence of varying IAT, etc. Some of the tests focused specifically on increasing ignition advance and MAP for maximum power on a turbosupercharged engine. Some focused on attaining maximum fuel economy. Some focused on allowing the use of lower-octane fuel.

All tests generally agreed that the use of water injection permitted great increases in knock-limited power, a result which I was never able to consistently replicate on my own car mostly because I'd run out of airflow (Greddy) and was already intercooled. That engine just refused to make much past 210 WHP no matter what I did.

From what I gather, the blending of alcohol with water was done principally to prevent the water from freezing solid. At 20,000 feet over Germany, this is a concern even during the summertime. Which brings me to this point:
I'm slightly curious about your statement here.

While decreasing IAT is generally desirable, isn't the primary goal of IAT reduction in a turbocharged engine to eliminate knock?

Very bad wording on my part. I am now looking to raise power by lowering IAT's (and thus reducing probability of knock) rather than just reducing knock with water injection while still having high IAT's.

Thanks for your input.

I even made this sick MSPAINT schematic... lol

https://www.miataturbo.net/attachmen...ine=1438286550

Then you need an intercooler. Good call on that, it's the better solution. If you try to push the absolute limits on pump gas, then water/meth injection could helpful.

Injecting water pre-turbo will cool the charge coming out of the turbo. It will work better than an alcohol. Depending on your IC location, and average speed, an IC might not be the best route.

Way to contradict all the logical conclusions in this thread, I award you one eggplant. :eggplant:

Using a fuel injector as a nozzle
 

True.

If the intercooler is located behind the radiator or your speed will be less than 30mph then you are completely accurate.

No, what you saw was a Skyline running an HKS AIC or Greddy REBIC with a bunch of extra injectors put in for fueling under boost. Didn't have anything to do with "intercooling."

Back in the day they did a lot of stupid shit, even on expensive cars.


https://www.miataturbo.net/attachmen...ine=1438533202

but it "worked" right?
so it must be perfectly acceptable to use in 2015 right?
lol