[Cummins Express]

so I've kept up on this thread for a few years, and now have a variant for you all. masterp2 shares some interest with me from another site, as well as being an owner, like me, of a diesel. I run a compound compressed 5.9l cummins. Low pressure turbo is a BW BHTB3 currently peaking at 37 psi absolute. High pressure turbo is BW S3A with a self made variable turbine. post high pressure turbo boost peaks at 82 psi absolute. An OEM aftercooler is employed post secondary, and no current compression stage intercooling is present, chemical or otherwise.

I have experimented with precomp WI in the past, and have recently been motivated to continue the R&D, but have some questions requiring your input. Knowing the harsh operating conditions the high pressure turbo operates under such as blistering inlet temps, having to ingest and compress a second stage of charge hovering in the 90 lb/min range, there is definite room for improvement in the high pressure turbo efficiency. Because of of the heat present in the inlet in excess of 350*F, my goal is to drop this temperature as drastically as possible. For lack of room for a second charge air cooler (CAC), in addition to the reluctance of adding that much more intake tract in an already dizzying amount of intake tract volume, precomp WI is my choice. Now for the nuts and bolts. I had previously experimented with WI at the inlet of the secondary charger with varying results and crude fabricating. I now wonder, after reading all 25 pages over again, if my purposes wouldn't be better suited by injecting pre-primary turbo? Two things come to mind...firstly, injecting at ambient pressure, with the minimal depression at the primary's inlet, vs injecting inter-stage, where the environment pressure is 37 psi and 350*F. Which would be more beneficial I wonder...injecting in a hot, pressurized environment, or the adverse, pre-primary turbo?

Additionally, I am talking about large quantities of water/meth, and am going outside convention regarding injection pressures and nozzle types. In my first attempt, I utilized furnace nozzles. High flow rates, and a hollow, spiral, 45* cone, placed an inch in front of the secondary's compressor wheel. I raised the nozzle's spec operating pressure from 100 to 200, hoping for more flow, and a higher atomization rate. I plan on going the same route, but with a different pump. I plan on belt driving a 3 stage high pressure pump on a clutch in excess of 1000 psi, or as much as 3000 psi. These pressures, of course, will be dictated by what the nozzles can handle, and some pretty crucial testing will take place on the bench before any mounting will occur. My initial thought is if I can find the nozzle will hold 1000+ psi, atomization rates should be quite high. The other option , of course, is a lower pressure system with narrow angle hollow nozzles that will provide high spray quality. I wouldn't mind going narrower than 45*, as this would allow me a little more space between the wheel and nozzle. All my findings in the past showed me that a hollow cone that avoids the wheel nut, yet is narrow enough and close enough to enter the wheel in its first 1/4' inch of radius showed no signs of erosion of impingment in the 10,000 or so miles i had it operating....at maybe a 30% to 50% duty cycle (I have a lead foot and see high boost frequently hehe).

All I need to do now is affect an injection system that will yield an efficient nozzle arrangement, and maintain that efficiency at say 20 gal/hr!?!? Is it feasable?

Chris