Pre-turbo water meth

By our very own Chris Foogle

yep, here's the deal.....the compounds are only days from going in, but I wanted to try chemical intercooling before I went to the extreme of plumbing in another air to air.

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 45* angle to stay close to the center of the wheel. The standard spec of the nozzle is a 5.50/45*A. 5.50 being 5.5 gph at 100 psi, 45* 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

 

Wow you have been busy, looks like a good setup for pulling and dragging to keep temps down with out having to spend a lot of money on turbo upgrades.

 

Actually water/meth is only reliable up to about 700hp. Anything over that and it causes problems due to the IAC being supersonic and the water no longer having the cooling properties because it is changing state too quickly.

 

Kevin, is that yours?

 

no.............its Chris Foogle's....CumminsExpress

 

Chris,

I have been advocating pre-c wmi for some time now.

Can you rationally explain what causes the boost increases?

How much pressure drop do you speculate from the added nozzle apparatus?

 

Well Kevin Dug this up from the grave....I ran the system for quite a while with good results. At the time my goal was to make a stock compressor act like a bigger one, especially when introduced higher intake pressures and temperatures from a primary feeding it. I had to take it off due a nozzle holder failure from some very rough off-road action. I stump-holed the truck and the weight of the nozzle/holder broke the feedpipe that it was mounted from. I never got around to re-designing a replacemnt, even though i meant to. There is....and still is...a lot of controversy about introducing liquid into a compressor's inlet tract and wheel. Some have had catastrophic results, and I suspect mostly due to inadequate atomization from poor pressure or nozzle, or after injection dribbling. Both scenarios will grenade a wheel in fairly short order. I took a lot of time researching nozzles and pressures. Quite amazingly, furnace nozzles offer a sub 10 micron droplet size at 100 psi (IIRC), a variety of cone angles, and solid, hollow, and semi-solid spray paterns. Nozzle placement as well as proper plumbing to prevent dribbling is paramount. I hit the nozzle with 200 psi, chose a vary narrow, hollow spray angle to keep the pattern radially close to the wheel hub and away from the tips, but not cover the shaft and nut with liquid to cause pooling and the "BB" effect. I ran the system for about 10,000 miles and never saw any visible erosion or damage. This is not to say, however, that even at 10 microns or less, dusting is a variable that HAD to have been happening, and it's a case of discretion as to when and whether to replace the wheel pro-actively or not. I would assume, that under normal duty cycles associated with only high boost activation, whether street or track, that the turbocharger would probably see it's service interval sooner than wheel deterioration would occur. But, there are so may variables that play into the scenario, that it's impossible for one shoe to fit everyone. I will say, however, that the more attention you give to detail and set-up, the better and safer results you're going to get.

I also never gave any results after installing the twins, which was the whole reason fro the idea anyway...to negate compression losses to heat due to a high secondary inlet temp from primary compression effects. I can't find my hard numbers presently, but I'll rely on memory to get as close I can recall. At peak boost, the primary was delivering 38 psi to the secondary at +/- 380*...yes the primary was overworking and making some hot air! without pre-compressor injection, the resultant post secondary pressure was 71 psi and +/- 450*. This is a scary high number isn't it? But, as aftercoolers become more efficient the hotter the inlet air is, it was still able to knock down the IAC to just over 220*. Mind you, this is PEAK numbers...full throttle, full fuel, peak boost and at 4000 rpm...and a highly modified secondary turbine. Now with the pre-compressor meth on, just as with the single charger testing, a rise in pressure was observed, though not as drastic...maybe 4 or 5 psi. What DID change however, is secondary outlet temp. IIRC, oulet temps were reduced by 100*, which may not sound like much, but in the world of thermal pressure dynamics, makes a huge difference in air MASS. I wish I could have spent the time and fabbed up a MAF and MAP sensor(s) that could handle the airflow to plot the air numbers, I think the results would have been remarkable. Since Kevin re-kindled this topic, I feel motivated to try it again and take the testing farther. After losing my access to lathes and mills, however, due to moving, the fabwork may be a tad more difficult For those interested, Aquamist was doing some fairly in depth R&D on the subject a few years ago, though I have not kept up with it since then. Might be worth checking out.

Killerbee....Having no real education or training in thermal dynamics I can only surmise my opinion from ration and mechanical logic. Since cooling the air charge should theoretically condense it in terms of mass, the result should actually be a drop in MAP, not an increase as my results, and even aftermarket mfgrs results show. So I adopt this theory. Injecting water in an airstream with the environment such as an intake tract where temps are potentially, and usually higher than it's boiling point at an ambient pressure, do we assume that the rise in pressure is due to the expansion property of the liquid turning to a gas aka steam? And if so, when we introduce the pressure influence on the water's liquid to gas state...what then? I don't know. The droplet size might predicate an elevated evaporation rate on a grand scale regardless of the pressure exerted on it. I would really like to know for sure as well. As the results don't jive with the properties that are occuring, but no one has questioned it and investigated! I can say, however, that the pressure increases could be as simple as more combustion energy acting on the turbocharger and creating more boost. The secondary gate setting predetermines it's rpm and consequently boost, but the primary is non-gated, and could actually be making more boost right off. I, unfortunately don't have any data on primary compressor output...either I didn't track it, or have forgotten it!! As far as the pressure drop from the nozzle, do you mean the injection pressure output of the pump from an added nozzle? If so, when I first fired the system, the large nozzles at the air horn in conjuction with a large nozzle at the secondary turbo caused the pressure to drop to less than 130 psi. While this is still in the operating range of all three nozzles, I was worried that spray pattern might be compromised. I put in a set of "325's" in the air horn, which brought final flow pressure up to 175 or so...again all from memory.

Anyone else interested in the subject? Damn long post again.....sry.

Chris

 

keep up the good work Chris....we love it man and hopefully we all can learn by yer experiments

 

LOL...experiments or parts destruction whichever sounds politically coorect at the time. My wife has a view for sure. She is still wondering why I changed out that secondary for some marine John Deere laggy bastard. She's just used to her '01 with it's HY35. You still have to DRIVE a fueled 12valve. Anyway...thanks for the post Kevin...did you get that off of CS or CF?

Chris

 

from the thermodynamics and fluids side of things i would think that adding the water pre-turbo would cause the water to heat up along with the air during the compression of the air in the turbo. the water would retain the heat more so then the volume of air. although it would help in the inter cooler to increase the heat transfer from the volume of air to the inter cooler. have you guys thought about water injection post turbo and pre inter cooler? just thinking about it engineering wise.