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Military DB4

I see, that makes sense, I will talk to Gary tomorrow. I would assume the exact location of the grooves is not critical right?

HX 52, that sounds like a pretty big turbo, is it wastegated? What truck/year did that come off of?
 
The grooves are 1/8 inch from the ends. There is a gap of .195 thousands between the two grooves.
 
vdb11 said:
correct this is the OEM turbo off a 6.7. But you make a good point slim. I do have a pressure gauge plumbed into my crossover so I am monitoring drive pressures now. Of course, the VGT is a very large turbo, or at least it seems to me. Now I know I am not running it at the boost it was designed to run to make big #s, but I would imagine the 6.7 from the factory doesn't run anymore than 30 psi (???).

I think I will keep the VGT for now, as I have little in it. But I am anxious to see turbonator try the VVT off the Dmax. But like always, I am open to suggestions.

6.2 turbo, haven't you run a couple different turbos??
Click to expand...
What the HE351ve is varying is the volute volume & the housing will flow well beyond what most realistic 6.5's could reliably make. I've got Holset's turbine map for the HE351ve - if memory serves it shows shaft rpm & airmass flow rates for 5 or 6 different VGT cage settings.

The relative sizing of the turbine & compressor wheels is what winds up influencing drive pressure to boost pressure ratio's with VGT turbine turbos. Essentially how tight/restrictive the VGT cage needs to be closed to generate the shaft rpm necessary for the comp wheel to create the boost pressure wanted.

I've seen a couple datalogs from a 6.7 truck w/ stock HE351ve that showed it could run right around 1:1 drive pressure to boost above 17-18 psi. Logs showed more like 13-15 psi drive pressure around 10 psi boost but limited data as the runs didn't spend much time around that boost level. The comp wheel is optimized for boost/pressure ratios somewhat higher than most 6.5-ers could/should use. The stock 6.7 Cummins VGT control logic runs higher drive pressures in certain situations to drive/force more EGR flow for emissions purposes. Basically intentionally further restricting the exhaust/raising exh pressure until they achieve the amount of EGR flow they need to control NOx emissions.

Don't know how well the folks on this thread's mechanical VGT control work(s)? In my discussions with one of the first guys to rig mechanical/boost referenced HE351ve VGT control on a 6.5, it sounded like it worked acceptably, but lost out on some of the best benefits of electronic intelligent control by including throttle position/load & current drive pressure into the logic deciding VGT cage extension/retraction.

Drive any of the late model VGT diesel trucks & note how quickly their turbo's spool. The boost:drive pressure ratio isn't very important in that brief/transient time spooling up & the quicker spool/lower boost threshold absolutely adds area under the torque curve that you can feel. You just don't want to be tied to a poor drive pressure to boost ratio in operating conditions the engine spends a lot of time at - particularly cruise speeds/loads.

Fleece is talking about getting back to finishing their control board (this winter) that will accept TPS & drive pressure inputs. Their prime market would be to allow the non-electronic 12valve 5.9 guys to gain the driveability benefits the VGT Holsets bring when they have effective electronic control. Don't expect this solution (if it actually gets to market) to be cheap, but it should be effective & you'll prolly have the easy option of an effective exhaust brake utilizing the VGT function.
 
SmithvilleD said:
What the HE351ve is varying is the volute volume & the housing will flow well beyond what most realistic 6.5's could reliably make. I've got Holset's turbine map for the HE351ve - if memory serves it shows shaft rpm & airmass flow rates for 5 or 6 different VGT cage settings.

The relative sizing of the turbine & compressor wheels is what winds up influencing drive pressure to boost pressure ratio's with VGT turbine turbos. Essentially how tight/restrictive the VGT cage needs to be closed to generate the shaft rpm necessary for the comp wheel to create the boost pressure wanted.

I've seen a couple datalogs from a 6.7 truck w/ stock HE351ve that showed it could run right around 1:1 drive pressure to boost above 17-18 psi. Logs showed more like 13-15 psi drive pressure around 10 psi boost but limited data as the runs didn't spend much time around that boost level. The comp wheel is optimized for boost/pressure ratios somewhat higher than most 6.5-ers could/should use. The stock 6.7 Cummins VGT control logic runs higher drive pressures in certain situations to drive/force more EGR flow for emissions purposes. Basically intentionally further restricting the exhaust/raising exh pressure until they achieve the amount of EGR flow they need to control NOx emissions.

Don't know how well the folks on this thread's mechanical VGT control work(s)? In my discussions with one of the first guys to rig mechanical/boost referenced HE351ve VGT control on a 6.5, it sounded like it worked acceptably, but lost out on some of the best benefits of electronic intelligent control by including throttle position/load & current drive pressure into the logic deciding VGT cage extension/retraction.

Drive any of the late model VGT diesel trucks & note how quickly their turbo's spool. The boost:drive pressure ratio isn't very important in that brief/transient time spooling up & the quicker spool/lower boost threshold absolutely adds area under the torque curve that you can feel. You just don't want to be tied to a poor drive pressure to boost ratio in operating conditions the engine spends a lot of time at - particularly cruise speeds/loads.

Fleece is talking about getting back to finishing their control board (this winter) that will accept TPS & drive pressure inputs. Their prime market would be to allow the non-electronic 12valve 5.9 guys to gain the driveability benefits the VGT Holsets bring when they have effective electronic control. Don't expect this solution (if it actually gets to market) to be cheap, but it should be effective & you'll prolly have the easy option of an effective exhaust brake utilizing the VGT function.
Click to expand...

I have noticed what you said about the drive:boost ratio changing. As the VGT opens, it seems to get closer to 1:1. I would imagine with the extra fuel I will have I can probably leave it maybe halfway open, and see how it spools. I want it to be able to spool pretty quick but be able to open all the way up so I don't overboost in very high rpms (like on a dyno, or winding it out while towing). My mechanical set up works well I think, but I am sure with electronics the VGT could be utilized much better. You are right the controller will not be cheap, and most likely not worth it for me.

As for exhaust brake, that is another back burner project I have been working on, and I am going to try it with some type of solenoid on a switch, when I will get to that I don't know.
 
It only has .270 plungers. I used the ag governor,which is causing some surging . Got the governor working better,and then promptly snapped the little db2 cam pin. Thought the pump seized,from too high charge psi,but its ok. I have everything I need to convert to the db4 pin. I also have some lighter governor weights to try ,but don't know if it will help the surge or not .
 
Surging can come from different things ,but not from running with no leafs.
 
Got it up and running again. Ditched the ag governor and installed the db4 cam pin . Runs great when cold,but hot it surges a little at high rpms. It starts hot ,but barely . 3500 pop psi is too much for three pumps in a row now . One was a bone stock military take out , fuel screw turned tight,but had 0 power and wouldn't start hot.
 
Not to try and show how much of a boot I am on building a pump. But are there any interchangeable or useable parts fro a db4 to a ds4. I have thought of going the mechanical but to be honest I love the electronic pumps adjustability. I do happen to have a db4 sitting in A cabinet at work. It has been there for a while so I dont think the boss man would mind me swiping it.
 
The DB pumps have a better cam ring, not a direct swap though.
 
Took my latest 2 plunger apart,and installed one of my better cam rings ,and a 4500 rpm gov spring . Runs pretty good,30 psi boost, with a H1C -18 cm housing ,and has been starting hot so far. Same pump wouldn't start hot before modded.
 
6.2 turbo said:
Got it up and running again. Ditched the ag governor and installed the db4 cam pin . Runs great when cold,but hot it surges a little at high rpms. It starts hot ,but barely . 3500 pop psi is too much for three pumps in a row now . One was a bone stock military take out , fuel screw turned tight,but had 0 power and wouldn't start hot.
Click to expand...

3500pop is probably killing the flow of the pump. Too much pop pressure raises injection pressure beyond what the plungers will seal.

I know with lots of tinkering, at least on our IH's, 2200pop is just about ideal for injection duration without increasing total injection pressure past stanadyne tolerance with a stock nozzle orifice. My 2500 pop sticks in my truck choke my fueling quite a bit, at least with stock diameter nozzles.

What sort of nozzle orifice diameter do your guys style injector have?

The 8cyl DB4 H/R is a stanadyne part, not a hybrid, I use it in my RD4 pumps.
 
I think the nozzles are .040,they are all the same . I also discovered Ford rotors are not the same as Chevy. The injection hole is offset backwards . Although some rotors have no offset,usually ag pumps and 4 plungers ,and can spin either way . High pop pressure does restrict fuel ,but it the motor runs better ,and will not flood when overfueled.
 
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