got...DIESEL?

This shows how far the nozzle carrier and feed pipe extend into the inlet tube





here's the two intake horn nozzles....an 865 cc/min and a 520 cc/min (@ 200 psi). Because I have the intake nozzles staged later than the pre-turbo nozzle, I have also placed a solenoid valve in line which is controlled by a Hobbs switch located in the intake manifold, which is set at 30 psi to turn on the intake nozzles.





This shows where I mounted the pump...behind the PDC on the fender, and the resevoir.





here's the hobbs pressure switch under the air horn that enables the air horn nozzles.





here's the pre-turbo assembly. Note another pressure switch that brings the pre-turbo nozzle on at 20 psi, another solenoid valve to keep it isolated, and cut down on afterbleed




here's the pre-turbo nozzle in action. It is a furnace nozzle rated at 5.5 gph, though at 220 psi closer to 8 gph (500 cc/min). It is a hollow cone to not flood the compressor wheel nut, and an 80* angle to stay close to the center of the wheel. The standard spec of the nozzle is a 5.50/80*A. 5.50 being 5.5 gph at 100 psi, 80* being the discharge angle, and "A" denoting the cone type...hollow in this case.




here's a close up of the same picture above. Note the narrow angle of the spray pattern keeps all the water towards the center of the wheel, negating any tip erosion. Note as well how the hollow cone of this nozzle nicely works around the nut, even though it is very close to the wheel. This nozzle sprays at 6 microns @100 psi, which is below the size that supposedly starts to cause tip and leading edge erosion. Time will tell, but wheels are cheap compared to the awesome advantages of spraying, especially in compounds, as I intend to finish in the next few weeks, to act as an intercooler.




so there you have it....now for the results. I really wish I had a dual channel IAC gauge, maybe in the near future, but for now, the seat of the pants as well as the boost and pyrometer tell enough of the tale to know the results. In high gear at a sustained 20 psi, and upon activation of the first stage (pre-turbo), boost increased to 26 psi without any accelerator change...the compressor section definitely became more efficient, acting as a larger compressor. As EGT's aren't high (800*) at this point, the turbo is in it's highest efficiency state, and the aftercooler is fully capable of cooling the current intake charge temps, there is no other aspect that can explain the increase in manifold pressure other than the injection pre-turbo obviously made a big difference in the compressor section of the turbo. Now under full acceleration at the 35 psi ceiling I have the turbo set at, my net manifold pressure climbed to 43 psi with the full system in operation, and egt's dropped by about 300*. I could never use more than about 2/3 throttle in 5th, or temps would pin the gauge. With the injection on, I max out at 1400*....still a bit high, but the compounds will take care of that.

So there you have it. Come to your own conclusions, but I believe pre-turbo injection just might be a way to increase a small compressor's efficiency past any other means available. And the benefit of pre-turbo injection will be even more invaluable in compounds to cool the air between stages without having to fabricate an air to air intercooler. By hitting the secondary with water, the end heat result will be well within the aftercooler's ability to efficiently casue a reduction in charge air temp. Follow that up with some post cooler injection and intake temps can be way down and consequently air mass very high. This will enable us to keep the compressor(s) in their peak efficiency range, and not push them into the upper reaches of their map, especially the secondary. I will know more when I can swing an IAT gauge as well as incorporate these theories into my compounds. Until then let the opinions and debate ensue...........

Chris

paccool

I hope I'm wrong but I think you will have trouble with the compressor wheel blade eroding from the water spray. I have seen fans that had water hitting the leading edges come apart and the turbo is operating even faster. Let us know how things go.

northslope

Very nicely done! It's always good to see someone take the plunge in a new direction. Especially one that is talked about but never explored!

PS if dad's and my wheel are the same as your hx why then you can bump up your spare wheel count to 3! I guess we can stop calling them compressor wheels and start calling them impellers

Rhino

This has been done and yes it does tear up the comp. wheels.

I do applaud your efforts but personally I don't know that I would have went though all this effort on a truck still running an HX35.

Eskimo

Me too in applauding his efforts... but I would certainly test it first on the least expensive turbo (should something go wrong) before I moved to compounds (like he mentioned).. Great idea, since HX's can be had relatively inexpensively.

P.S. I remember reading a little about having more than one breather.. how is 6 working out for you? (You can PM me if you want to keep the thread on-topic!)

Rhino

Sorry I missed that part. Either way the injection of water pre turbo does have an adverse effect on the comp wheel.

HOHN

I disagree. If it's injected far enough upstream so that water can vaporize completely, then there will be NO adverse effect on the turbo.


But I have say that injecting water PRE turbo and injecting water INTO the turbo are COMPLETELY DIFFERENT.

Injecting water directly into the turbo as illustrated above is imo a bad idea. Turbos are designed to compress air, not air/water mixture. Wheel erosion is just one problem you may have. As the wheel erodes (and it will), it will cause thin spots that will weaken the blades. Weak blades quickly become broken blades, which will cause a catastrophic turbo failure .0000486 seconds later.


Injecting water pre-turbo is a good idea, but it HAS to be done much farther upstream so that the water has time to completely vaporize.

You want to cool the intake air BEFORE it hits the turbo, not IN the turbo itself.


If you are thinking about twins, then the proper place for your inter-stage injection would be in the "cold pipe" as close to the big charger's outlet as you can get it.

Think about it. If you want a cooler like a tranny cooler to work its best, you need to have it arranged such that the the cooler is at the point where the tranny temps are hottest, and the ambient air is coolest. In other words, maximum temperature differential yields a faster RATE of cooling, and therefore a better DEGREE of cooling within a given time.


So, for water injection, you want it injected where the intake air is the hottest, which is right at the turbo outlet.


With a single turbo on an intercooled truck, you don't want inject the water right at the turbo outlet because it reduces intercooler efficiency.


But with twins, you are using your injection between stages as a form of intercooling, and therefore it should be as close to the big charger as you can get-- it's safer AND more effective when setup this way.

jmo

Rhino

I agree, if the water has time to vaporize pre-turbo would be fine. I just do not see that happening on this application.

got...DIESEL?

all valid and thought of points. When I get the second turbo on, I had contemplated moving the injection point upstream to the primary outlet. I worry however that all the water won't vaporize at the temps the primary will be delivering, and consequent interstage pooling might be more catastrophic than a sub 10 micron barage at the wheel. After talking ALOT with aquamist, who has been playing with pre-turbo WI for years, they found that sub 20 micron induction produces negligable effects.....I said negligable, not non existent. Additionally, if the injection pattern is kept to the inside 1/2 diameter of the wheel, blade velocity is substantially lower than at the tips. I know erosion will occur, but ponder the duty cycle. This truck sees light street duty, and if the WI is on for 20 seconds at a time once or twice per day, uif even that, the overall effect is diminished with time. To me HX35 wheels are the easiest sacrificial component, providing one keeps check on the condition that is. If I slip and let one go that takes the turbo with it then I have learned my lesson....break out the welder and do the plumbing for an air to air intercooler!! One way or the other, the stages have to be cooled to extract peak efficiency IMHO. Everybody is talking CAI's, ram air and the such to keep inlet temps down, but no one sais anything when we strap on a hairdryer that cranks out 250* inlet temps to the secondary, what's the solution? Turn around and close our eyes? Just because none of the big dogs are making an intercooler system, it must be okay right? Or are they just overcompensating with compressors they don't need to be using when a smaller one will do? I don't know the answer, but I know if you keep the turbochargers cheap, ongoing maintenance is also cheap. They don't come cheaper than a BHTB and a stock 35. This is where my quest began. And don't get me wrong, I'm not opposed to fabbing up an intercooler, but if WI will work with reasonable side effects then....???

Anyway my two cents more. Rest assured I didn't jump into this thing blind. Months of research and decisions went into it. While I knew all of the popular reasons NOT to do it, do we know the unpopular reasons FOR doing it? That is what I set out to explore. And as I get my IAT gauges up and running and other goodies to monitor vitals, I'll deliver the results. I don't mind some set-backs. I value all your opinions and views BTW, so let's keep hashing it out. Everything we do to these trucks starts out in controversy until enough people say its okay, so isn't everyone anxious to know how this turns out? Time will tell, but alot of us know it isn't a set it and forget it operation, and not for the faint at heart. It is a danger zone granted, but that's the way R&D goes right?

Thanks guys keep it coming.

Chris

BTW...the breathers work well, but tend to bleed quite a bit....it's another trade-off. And if anyone is curious what I'm doing with all the plumbing on the exhaust manifold....I'll tell ya when it is tuned correctly and working flawlessly

signature600

I seem to remember something about a BOV!

What do you mean the breathers "bleed quite a bit?"

Good discussion on the water injection, BTW!

Chris

got...DIESEL?

got tired of all the throttle sw activated BOV's. The market isn't there (yet) for the aftermarket to put the work into a truly dynamic BOV, so I designed one that worked on pressure differentials. It's not always when you close the throttle completely that the turbo surges. If I'm pulling a load or grade and just feather the throttle a little, it'll flutter at me. If I am grabbing gears hard and redlining every gear, the surge is more pronounced. The notion that diesels don't benefit from BOV's because they don't have throttle plates is BS. It's all in the air flow amounts and pressures. Anything under about 20 psi and the engine can consume the excess air by natural revolution. More than that though and there's more volume than can be ingested and hence the surge. I'm just playing with tuning it now to work on any truck regardless of boost levels. Anyway....'nough about the fictitious diesel BOV eh?

Breathers....I am using the push in type, and where they fit into the rocker cover tend to weep some oil becasue the holes are just a tad bit too loose, and a thin cover to begin with. Amount of oil? Not too much, but enough to make me want to change them. I have to wipe the covers every month or so to keep them clean. I am going to weld bungs on the covers and use the clamp on style instead. The breathers themselves don't seem to allow any oil out though. 6 is overkill, but I like everything to match, and 6 looks better than just a couple.

HOHN

The water will vaporize if your nozzle is giving you the sub 10 micron size that you think it is.

Remember, it's not just temp that causes vaporization. If you have a fine mist being injected far upstream, then you will NOT get pooling in the tract.

Even if your big turbo's outlet temps are 40°F, your water injection charge will still vaporize completely if the nozzle is any good. In your case, using the Snow 220psi pump will ensure you have plenty of atomization.


Your point about the duty cycle is valid, but if you can move it upstream, have NO risk, and get equal or better performance, why would you NOT do so??


jlh

got...DIESEL?

completely agree Hohn....no damage is alot better than major, or minimal damage. If I move it upstream after the primary goes on, I would switch to a wider pattern nozzle. I have another 625 to play with, and they have a real wide pattern. Side by side, as far as the naked eye can detect anyway, the mist out of the furnace nozzle was a least as good if not a little finer than the snow nozzle. When you're moving these kind of flow rates, atomization becomes a challenge for sure. But after talking with Delavan at length, they say at 100 psi, and with a higher viscosity fluid such as #1, their patterns are less than 10 mics. With water, and at pressures greater than 100, the droplet size will decrease substantially. BUT, they don't make a nozzle with a cone angle greater than 90*, so for pipes and other "shallow" chambers, Snow's nozzles are king.

Today I temporarily hooked up my Fluke Rapid Temp sense into the intake plenum. I will be able to tell temps at no injection, pre-turbo only, and with the full system on. I will then move it to the turbo oulet to see oulet temps both with the first stage nozzle on, and off. I would really like to hook up an air mass sensor. Those numbers would be the most beneficial!! Thought of using a GM mass sensor, giving it a reference voltage, then reading the ouputs and converting them against known GM parameters for mass levels.