P-pump AND VP44 guys come on in......

[BWillard]

Thinking about a P-pump conversion and although I've had a 12V before, I never got a chance to learn that much about them. My question is, what would one have to do to a P-pump to get it to run like a VP44 with a 120HP Comp box? Delivery valves, GSK, etc. I would also add a valet switch to somewhat compensate for turning the box down for running around town. Smoke is not an issue, as I'm kinda smokey even with my Comp off now with the Mach 5's (old version). Just want some things to think about when collecting parts for such a swap. Also what is the best pump to start with, 160, 180, etc.



TIA,

Braden

 

[SConklin]

If you can get over to DTR, or F1 Diesel, talk to Don M about his opinions of P-pump conversions... seems to be a common opinion. I don't know from experience though. If the VP can be kept alive through proper setups, it fuels nicely in modified form, and is highly streetable...

If a hot rod VP44 can fuel Mach 7's, the catcher takes care of the deficiency in the bottom end, the redline fuel box takes care of the top end limits, and a FASS or RASP keeps it nicely fed, clean, and happy... why convert?

(I know... reliability still... but just trying to give something to think about. )

 

[Devan Manis]

i read over on the DTR about i think two guys(haven't read it for a while)did the conversion and got it to work well for them http://www.dieseltruckresource.com/dev/showthread.php?s=&threadid=38179&perpage=15&pagenumber=1 Maybe that will help

 

[RonA]

Biggest issue is getting a good pump. Make sure it is put on a stand and checked out before you put it on. Otherwise you will chase your tail checking everything else.

 

[Hohn]

. My question is, what would one have to do to a P-pump to get it to run like a VP44 with a 120HP Comp box?

TIA,

Braden

You never will get a P-pump to run like a VP44 with a Comp box. Yes, you can make the power, and yes, it will deliver the fuel. But the power curve will be narrower in RPM range and and truck will be less streetable.



The P-pump will fuel enough to drown a fire hydrant, but because it's a "dumb" pump that cannot vary timing, it has reduced flexibility and in powerband and less streetability.



Save the p-pump conversions for those guys who sledpull and don't need streetability or MPG.



Flame suit on, p-pumpers.



jlh

 

[jmeehan]

Save the p-pump conversions for those guys who sledpull and don't need streetability or MPG.

Don't the P pumps get better MPG? Maybe it's because I drive a HO, but it seems the 12 valvers get better milage. I'm considering a swap for simplicity and MPG.

 

[RonA]

Justin.

I have never had the pleasure of driving a vp44 equipped truck. i am running Jammer 2s in my truck with a Dodgezilla/14 on top. I would like to know at what rpm you reach 15 lbs of boost on the electronic motor. I have heard they run very nice. I can't hit 15 lbs with the twins untill about 1550. How much faster does the electronic motor get things going? I saw that you are running a similar size injector.

Thank you.

Ron

 

[Hohn]

My truck is not a good representative to carry the VP44 banner in the spoolup war, so to speak. For one, I have modified (ported out) the turbine housing which slows spoolup, and I live at high altitude.



My spoolup was about the same as yours before I modded the turbo. Before this, I could hit almost 15psi at 1500rpm (at sea level). This was with the EZ and DD2s and the tiny stock charger.



I'm not sure the VP really spools any faster than a P-pump. This is because it depends on the setup of the P-pump. The p-pump can have wildly different performance characteristics with just a couple screw or starwheel turns.



The VP DOES have a wider powerband in terms of RPM. Now, this assumes a stock P-pump-- no GSKs. Look at the torque curves in the latest TDR mag and you can see this. The VP trucks come up to peak TQ and hold it for quirte a while. A P-pump comes up to peak tq and immediately dives back down.



My reference to fuel economy is stated because most p-pump conversions are done in search of mega-fueling, and the pumps are not set up for MPG, just smoke and HP.



True, a P-pump can give great mpg. But if you set one up for 550-600hp, forget about that.



P-pumps have their place, especially among those who prefer all mechanical pumps or just have different goals. It can be setup to give great mpg, or great hp.



The VP gives a more optimized combination of HP and mpg, imho. For a street-driven truck (smoke being an issue), the VP is a better way to go.



JMHO, as always.



jlh

 

[BWillard]

This truck will be, in about a year and a half the second truck. Most likely I'll be pulling with it and towing with the new one. Maxium fueling is what I'll be looking for. This year and a half window will give me the chance to start collecting parts and $$$$. On a side note, my VP has been acting really bad lately..... stumbles, dead spots (at various RPM ranges), sometimes have to coax to start, etc. . I WILL NOT replace this pump with another VP, just like the automatic, it only had one chance This problem started partly because of the fact that I drove 2 days with the FASS not pumping and blaming it on the pressure guage isolator and it turned out to be a relay on the FASS. So I will try to limp along for awhile till it just takes a #@$%! and an unsuspecting P-7100 makes it under the hood. Plus, I'm up for the challenge

 

[Huff N Puff]

I agree with Captain Hohn

The VP is a much better injection pump for the street,I'm still running the original injection pump on my truck. On the street with the Edge Drag Comp. turned of I have a very streetable 500hp very little smoke. When the Edge is turned on at 5x5,I have an awesome 640hp 12sec truck that has never seen 1500 deg. on the EGT gage . Sounds like you are already convinced the P-pump is the way to go though. One more thing to think about you could buy 4 VP44s for one P-pump conversion that will need alot more work to tune after.

 

[Jetpilot]

Converting to a p-pump is not all that hard..... But getting it to work WELL is another story. As stated above a VP truck drives much better than a p-pumped truck. If street manners, towing, and drivability are your main desires I would stay with the VP. But, if all out HP is what you want you might consider a p-pump conversion, although the hot VP trucks are approaching the power output of the p-pumped guys (well all except scheid, enterprise etc. ).



Doug