VP44 Comp Box on DS4?

[88 Ford]

So I have been doing some thinking after I first noticed the similarities between a Bosch VP44 and the Stanadyne DS4. I think it is possible to adapt a Cummins Fuel Comp box to gain additional fuel solenoid closure time that the ECM cannot provide. The best boxes would be tha control fuel only. I'm not sure a timing and fuel box would even work plus I would want only the stock ECM controlling timing anyway. The harness would obviously have to be spliced into to make it work but here is how I think it would need to be wired.

The Fuel Inject Control on the DS4= Data Link(+) on the VP44.

-On the VP44, the timing and fuel control signal are both on this same wire but all I think the DS4 would need would be the Fuel Inject Control Signal.

The Diesel Inject Signal on the DS4= Data Link (-) on VP44.

-These are pretty much the return for both signals as I understand it.

Both will have a power and ground wire.

The VP44 has an engine reference signal sent to the pump as well. I'm guessing the optic sensor position signal will need to be tapped and sent to the comp box as well. Maybe it isn't needed. But I am guessing that it is.

Another signal that is sent to the VP44 is the fuel shutoff signal. I'm guessing that will need tapped as well coming from the fuel shutoff solenoid.

The only signal on the VP44 that I have not seen in any Chevy schematics is the low idle select. Is there a signal like this anywhere on the Chevy 6.5? Also I'm not sure how much this signal is even needed.

The last thing that I believe would be needed is to tap into the fuel solenoid pump signal. Essentially a wire is tapped into it and adds additional pulse to the fuel pulse based off the reference engine data. It will hold the fuel solenoid closed longer than the factory ECM is capable of doing which should add quite a bit more fueling capability. What do you all think? Anything that I have not thought about or that I’m wrong on?

Also I found some wiring diagrams of both pumps so you guys can compare but I can't seem to get them to upload on my phone.

 

[ak diesel driver]

are you going to try this?

 

[THEFERMANATOR]

Give it a shot, but I don't think you're going to get much more fuel out of a DS4. Mathematically a DS4 pushes 120MM3 of fuel per pump, and were already able to obtain 92-96 MM3 of fuel from an average DS4 at pressure and RPM's of around 3K crank speed(I'm not talking theoretical here, but actual measured fuel delivery on a bench). This seems pretty good to me by the time you account for pumping losses through the pump, losses through the injector, and RPM losses from being able to fully fill the plunger bore. Would be interested to see if anymore can actually be obtained or not.

 

[88 Ford]

are you going to try this?

Yes I would like to or I would even help someone attempt this if they want to before I am at the point where I can do it. My first project is adapting a Ds4 to my 7.3 IDI. From what I can tell, is that it doesn't matter the direction the Ds4 spins. The optic disc and stepper motor seem to work in both directions as far as I can tell.

 

[88 Ford]

Give it a shot, but I don't think you're going to get much more fuel out of a DS4. Mathematically a DS4 pushes 120MM3 of fuel per pump, and were already able to obtain 92-96 MM3 of fuel from an average DS4 at pressure and RPM's of around 3K crank speed(I'm not talking theoretical here, but actual measured fuel delivery on a bench). This seems pretty good to me by the time you account for pumping losses through the pump, losses through the injector, and RPM losses from being able to fully fill the plunger bore. Would be interested to see if anymore can actually be obtained or not.

I too have wondered how much extra the pump can push with the extra solenoid closure time. If I can get everything to work, I would probably have Justin from R&D Performance build me a pump. I would definitely test this on the pump that I have sitting on the shelf first though. That IP is on its way out lol. Anyway, is that 120cc calculated by the plunger stroke? Also as far as 92-96cc goes, what is the solenoid closure time on that? Those are sober of the things that might affect the test volume. Test parameters are important.

 

[88 Ford]

So I was looking up the plunger size in a VP44 and it has 3 plungers that are 7mm. The DS4 has 4 plungers that are .310 or roughly 7.87mm. The cam ring has more lift but with the DS4 having more plungers, I can't see why it couldn't push close to the same fuel as the VP44 with stock internals and a tune. From what I read, the VP44 pushes 175cc max. The the DS4 in a perfect situation can supposedly do only 120cc max. Where are those numbers from? A test bench? And if it is from a test bench what parameters is it tested under? Depending how long the fuel solenoid is held closed, that will have an affect on fuel output on the bench. IMO, there should be more fuel available. Even with stock internals.

 

[THEFERMANATOR]

The 120 is from somebody who did the math on the plunger size. The actual flow numbers on a bench where the ECM is taken out of the equation, and a stanadyne control box is used that can request max fueling is 92-94MM3 of fuel at 3000 RPM's on average through a test orifice. The same test was done with a 6.5 turbo injector, and similiar results were achieved. So this isn't ECM limited output, but the pump itself. Even STANADYNE doesn't list the output as being that high on them.

 

[88 Ford]

OK. Interesting. I do think it would be possible to increase flow to a great degree. I was talking with 6.2l about it quite a bit. One thing I was thinking about as well, is that the transfer pump would need adjusted to compensate for the additional flow.

 

[Will L.]

The difference in what happens when you jack up the incoming fuel pressure is what takes the db pumps way in excess over the db pumps. Any of the ds pumps i e heard of, the bell curve peaks around 19-20 psi with a 3/8 inlet. Db pumps tend to peak 26-27 psi with a 3/8 intake.

When your trying to max a pump, time spent on the bench is golden. You can set up an ecm to call for way more fuel than the body is capable of delivering. Kinda like me trying to go fast in my hummer. Pedal can smash the floor, but im not going to catch that Hennessey Venom GT -haha.

My old pump guy, Scott from J&S Diesel, was convinced he could hit the 130 range with a ds, but afaik never made it happen before he died. He smashed it many times with db pumps. If he said it was possible, I'm sure it is- but it will take some $ and time.

I'll never run a ds until someone creates a replacement for the drive by wire for it, but would love to see someone push 130 with one. Fingers crossed...

 

[88 Ford]

Yeah you definitely don't want to get the pressure to high if I'm understanding what you are meaning. I think a slight bump in pressure would be beneficial though.

Did he ever mention what he would do to the pump to get that? Justin at R&D Performance said he thought he could work it over to about 150cc but it would take some testing.

 

[Will L.]

He mentioned some things, but its been way too many years ago.

150 from a vp44 or a ds4? One's impressive,the other impossible.
Anyone that can get 125 from a ds4 and puts up a video showing it on the bench will gain an amazing level of fame, and probably most of the work from everyone. Even if they dont need or want to run near that volume, the skills of a builder knowing what he is doing will earn business.

If Bill Heath didnt have the lsr, im willing to bet he wouldnt have half the sales.
Unique Diesel has a quick 1/4 mile truck that shows a few people he is worth paying attention to.
Look at Conestogadiesel- All thier fame is about the moose/ bull moose.
Keep in mind R&D is used to the ford pump- most of it translates, but not all.

 

[88 Ford]

Yeah I was meaning the DS4. What we talked about was just in a quick conversation but I may be mis-remembering. I see no reason that you can't get more out of the pump though. Increase flow through the pump and other things as well. I understand that is simplified but he has gotten 150cc out of a DB2 and over 200cc with a DB4. Those are completely different pumps from a Ds4 but there are some similarities. I trust that he should be able to get more than 120cc with a modified pump.

 

[88 Ford]

Its kind of like the fact that for the longest time a VP44 couldn't be modded much above 200cc but now they are able to push over 500cc.

 

[ak diesel driver]

I didn't have a lot of luck talking to Justin about the DS4

 

[THEFERMANATOR]

Yeah I was meaning the DS4. What we talked about was just in a quick conversation but I may be mis-remembering. I see no reason that you can't get more out of the pump though. Increase flow through the pump and other things as well. I understand that is simplified but he has gotten 150cc out of a DB2 and over 200cc with a DB4. Those are completely different pumps from a Ds4 but there are some similarities. I trust that he should be able to get more than 120cc with a modified pump.

But nobody has done anywhere close to 120 now that I'm aware of. Theres only been a handfull of modded DS4 pumps, and the only successfull one I rememebr was pushing around 96-97mm3 of fuel at 3000 rpm's. It was pushing a bit over 100 peak, but it fell off pretty quick after 3k rpm's. The problem with that pump was the tuning though. It was pretty much a nightmare to get right. The pump and ECM had to be set up together on a STANADYNE test bench before it ever went into a truck. I remember even with a modded ECM, they still had to run a #2 resistor in it to furthur limit the ECM just to get it to idle. Then theres the HEATH pump, but ZERO details on what is done to it if anything.

 

[Will L.]

200 on a db4? Yowza, that could scoot a truck. Thats i to bigger injector lines and seriously enlarged injectors.

I wonder if that is running on the hcpa ford injectors...

 

[6.5L]

The problem with any of the DB/DS style pumps is beyond tuning, and is a limit of the internals and design. Depending on different spots. Right now, one of the biggest limit of the DS pump comes in the fuel solenoid opening and closing. Tuning can only get it open for so long. Heaths pump has somehow overcome this, and talking with my pump guy, he believes it is because Heath has used a different solenoid from another type of Stanadyne pump (there is a lot) that can be commanded differently through the tuning. Hence how he is able to get more fueling. Still limited though after a point because of internal changes and charging/discharge port locations. If I recall, the DS ports are slotted where as the DB are not, which allows for more fuel duration into the charge and discharge ports. So why we see bigger fuel rates stock DB vs stock DS. I could be a bit off. Been a while since I've had one apart. As far as potential goes, the DB platforms have a huge potential for more fueling because of different cam rings, plungers, shoes, leaf springs, and the ease of changing mods internally.

 

[6.5L]

I did find out how to overcome all of that though. I did just ordered an inline 8 cylinder pump lol should be here next week. That's when the fun will begin.

 

[88 Ford]

I didn't have a lot of luck talking to Justin about the DS4

He's always been pretty busy. I do know he has a lot on his plate building his current products and expanding the Ford IDI product line as well. He hasn't talked a great amount with but just thought it was possible to get more fuel. I don't need an insane amount of fuel, it would be cool to get 150cc though.

 

[88 Ford]

But nobody has done anywhere close to 120 now that I'm aware of. Theres only been a handfull of modded DS4 pumps, and the only successfull one I rememebr was pushing around 96-97mm3 of fuel at 3000 rpm's. It was pushing a bit over 100 peak, but it fell off pretty quick after 3k rpm's. The problem with that pump was the tuning though. It was pretty much a nightmare to get right. The pump and ECM had to be set up together on a STANADYNE test bench before it ever went into a truck. I remember even with a modded ECM, they still had to run a #2 resistor in it to furthur limit the ECM just to get it to idle. Then theres the HEATH pump, but ZERO details on what is done to it if anything.

Hmmm I wonder if running an Adaptronic stand alone ECU would make it easier with its tuneability? It costs about $1600 but has endless possibilities tuning wise due to the adaptability of how it was designed. That might make tuning and adjustability easier.