Engine/Transmission (1998.5 - 2002) VP pump + cut delivery valves = ?

[Blacksdieselhp]

I have heard Van Haisley's truck run with the modified VP on it. I don't know how it runs, but it idles awesomely. It shakes the whole truck. I told him I didn't care if it would run, as long as it idled like his. (ha,ha) He said the truck ran very strong, but it wouldn't idle long before loading up and going dead. I don't know about you guys, but I can deal with that for more power. Don't worry, if anyone can build one, sooner or later, Van will.

 

[HoleshotHolset]

There's still hope!!

Here's a closeup of the 'snubber valve' that sits inside what I'll still refer to (for lack of a better term... ) as the delivery valve holder in the VP-44:



I'm thinking some there is some potential in this area for increased flow... . much in the same way that I originally thought... back when I thought this was a simple DV swap like the P-7100's, VP-37's have in 'em.



The research continues... .



Matt - having fun learning 'bout pumps!

 

[HoleshotHolset]

Solenoid valve

Here's a shot that shows how the solenoid valve controls the injection event... . you can clearly see how the high pressure fuel (in red. . ) is being held back by the solenoid valve:



On edit: When the solenoid valve 'opens', the injection event is stopped. This is the 'fun' valve to tap into electronically because in essence you are increasing your injector pusewidth... . or increasing the duration of the injection event... just like in gasser cars.



Since the solenoid valve has a 2-wire hookup, the PCU (pump control unit... the brains INSIDE the VP-44... ), nor the ECM don't really have any clue as to its position... making it an easy target for folks after more power... in the form of boxes and so forth that tickle this solenoid to stay closed longer... .



Matt

 

[Diesel Freak]

Great Research Matt. Keep it up!

 

[aphyfe]

More info?

What is the story? Any new info yet?

 

[clawson]

Yeah i am very interested. I would love to learn new info about the vp44 and any ways to make it deliver more fuel

 

[bighammer]

Re: Not so encouraging news...

Originally posted by HoleshotHolset

Well... after finally getting the 'DV holders' out of the distributor section of the pump and taking apart a lot of other stuff... I came to a few pretty solid conclusions.



1)The VP-37 and the VP-44 are more different than I thought.

2)The VP-44 doesn't have the same DV arrangement as the VP-37.



The VP-44 basically has an orifice on the opposite end to where the injector line hooks up on the 'DV holder'. The diameter of this orifice could be modified beyond the OEM diameter of 1. 012mm for more fuel flow... but who knows what that will do to the injector crack pressure.



The rotating assembly inside the distributor from this pump is seized... and is resisting my every attempt at disassembly with common hand tools. I shook an angry fist at least 10 times in its general direction... and swore at it... but that sucker is darn near welded together.



I am going to investigate #2 up above even further, but at this point it isn't a simple swap of DV's like I had originally thought.



Now I'm on the search for a VP-44 manual... one that will show some innards of the pump.



Matt

We tried to take one apart last year at a GLTDR gathering at Precision Diesel Injection near Lansing. Marty Tompkins (shop owner) had a dead pump that he and Steve St Laurent tore into as far as they could. There did seem to be a point where disassembly turned into head scratching. I think they ended up giving up on it to move onto other things.

 

[HoleshotHolset]

I don't have the means to take apart the snubber valve assembly at my apartment... . so I'm at a stalemate.



I need a bench vise and some vice-grips... . but I don't have anything to bolt the bench vise to.



The downside to disassembling the snubber valve like this is that I'll probably ruin it... . or it will resist my every attempt at taking it apart.



Matt

 

[Ryan]

I woul think that an increas in the diameter of the long hole from the valve cone area to the line attachment point could be benefficial, depending on what the size of the hole is. It could help flow.



Any changes to the orifice would have to be balanced with changes to the spring as well to maintain the correct balance for cracking.

 

[StakeMan]

Here is something to look at.



http://www.dieseltruckresource.com/dev/showthread.php?s=&threadid=38846



http://www.dieseltruckresource.com/dev/showthread.php?s=&threadid=38942

 

[HoleshotHolset]

From the second URL: "The Pump:

Considerable amount of resurch has gone into this pump and the shop that is building it has spent a considerable amount of time in resurch and development. The pump flows between %13-%18 more fuel than a stock vp44 on the test stand which results to about 50 more horsepower on a non HO pump and 50+ for an HO pump depending on how large of an injector is used. The pump is made with bosch parts and is rebuilt using bosch specifications. So the reliability and durability is the same as any reman pump you would recieve directly from bosch. The pump is tested, the timing calibrated, and the PCM reflashed on a Bosch EP815 electronic test stand. This is the test stand that Bosch uses to rebuild its vp44's. The pump does not consist of cut delivery valves because cut delivery valves causes problems with the injector pop off's and throws timing so far off that it cannot be set correctly or adjusted for. This pump is built to get the maximum amount of fueling possible out of the vp44. "



Interesting...



Cut DV's may still work on my VP-37, though... . because it's a completely different beast than the VP-44. I'll admit that I was making bad assumptions about the similarities between the VP-37 and the VP-44.



The research continues...



Matt

 

[fox]

Matt, keep doing the research and find out what it takes to rev this e-pump to 4500!!!!

John

 

[HoleshotHolset]

FWIW: The VP-37 in the VW TDI's will alow the 1. 9L to rev up to about 5000rpm (2500rpm injection pump speed).



Maybe the solenoid valve on the VP-44 would prevent rpms that high. Keep in mind that the poor little solenoid valve has to operate for every injection event. With 6 cylinders at 4500rpm... that's a lot of injection events.



Getting enough 'fill time' at 4500rpm also presents problems... . the VP-44's are sensitive enough to changes in fuel supply and pressure way below 4500rpm.



Matt

 

[Gary - K7GLD]

I guess the real question is whether the solenoid valve in our VP-44 is the same. or can function the same as the one in the VW. With other seemingly basic similarities, it would seem unusual Bosch would have a unique valveing arrangement just for the VP-44, especially if they already had another in service capable of operation in the VP-44...

 

[HoleshotHolset]

The VW doesn't have a similar solenoid valve setup... .

Information on them is a bit scarce... much like the VP-44.



I'll post more info as it becomes available.



Matt