24V vs. 12V Pop-Off's

Smokem said:
You will lose velocity but gain high sustained RPM fuel recovery.
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with which lines? the larger or small ones are better for high rpm recovery?

I am by no means turning "big" rpm, but plan to leave the line just above 4500 and depending on conditions turn anywhere from 3700-4200 on the track, I am actually hoping to get my truck to be making its best power around 3700-4000rpms, not sure how its gonna work tho.
 
Soup Nazi said:
A VP injector that has not been converted will only run worse behind a P pump with large lines. It is not just resetting pop pressure. For the best results on an unconverted VP injector you need to run a small ID line. .082-.084 MAX. And it will still run with less than optimum results.

The pulse from the pump travels at roughly the speed of sound through the line when the system is properly matched. The length of that pulse is what changes with diameter. No matter what you do, the pulse will get shorter AND the pressure curve of that pulse will shorten with increasing the diameter of the "road" or "tunnel" that pulse travels down. Pretty simple to understand why the line diameter is sized in accordance with of the fuel slug being pumped and the pressure curve needed.

Think of it like this: Imagine a line diameter with an ID of 1/2 inch between the pump and injector. How much pressure could that pump really build up with a diameter that large? It would not even be enough to open the injector, much less inject ANY fuel. The same thing applies in any line diameter change. Increasing diameter lowers the overall pressure, speed and time the fuel has to overcome the injectors spring.

A VP injector is designed with delivery curve much lower and a spring pressure much higher. Forget the fk'n opening pressure. Thats a trojan horse that 99% of vendors and purchases get hung up on. The pressure curve the VP injector spring operates at is mucho higher than a P pump injector spring. It requires a higher pressure to keep it open throughout the delivery pulse of fuel coming from the pump. Resetting the pressure to a lower point only lowers the pressure required to initially open the stupid thing, not the force/pressure required to KEEP it open. The P pump has a crap/low pressure curve compared to a VP and of course A CR. It needs a spring with a low pressure curve required to open it and a pressure from the line feeding it.

We have been coverting VP injectors since the early days. Not just resetting opening pressures. Thats a novice's game.
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Thanks Don.
Brandon
 
I never changed the pop off on my mach 7s when i p-pumped my truck. I have .093 lines and 535 cc pump that is set at 26*,for now, and it runs/drives fine. Do i need to get them changed? And what will it help by doing so?
 
If you have high pop off pressure, the atomazation will be good which gives good starting and smooth idles, but crank up the motor to 5k and the pop pressures increase and limit flow, possibly blow out a nozzle and back the pressure up to the cam in the pump. Start off with low pressures and you have poor starting, excessive idle haze and if street driven, bad fuel economy. This is why pullers run the big lines and low pressures. Your pump is going to move the same amount of fuel whichever way you go. I see no point in running .120 lines and .093 tubes with stock holders.

I run .120 holders, lines and delivery tubes to honed bodies with 6x18 nozzles. This should allow for max fuel at safe pressures with as minimal wear as can be had. plus i was wrong on my pop pressures, they are 3900 not 4400.
 
ILLINOISRAM said:
I run .120 holders, lines and delivery tubes to honed bodies with 6x18 nozzles. This should allow for max fuel at safe pressures with as minimal wear as can be had. plus i was wrong on my pop pressures, they are 3900 not 4400.
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with what charger though? im sure your running something bigger than a 2.6 with all that fuel...
 
2.8 hx50. My brother runs the same with a sb66 but it will deff. not clean it up. The tubo for his new motor will for sure be bigger.
 
I might try some back to back runs between my .093's and my stock lines to see if there's any difference.

Tj, Baileys p pumped 24v is getting .084's lines so we'll how that pans out
 
Why the fuss over DV holders? I see people buying modded DV holders from vendors who open the holes up. Why? Do they think the orifice in the holder is too small?

For the record we opened up some holders 7-8 years ago. What happened? About nothing. Anyone know why?

Buying modded DV holders is a waste of money. Well, maybe 20 HP if you get the sizing right and flow equal, but one cant get the flow equal between the holders without reverse Extrude Honing and balancing of the holder. I have a sinking feeling the sellers of this stuff dont even know how they work. We figured it out after pushing about 5 cubic tons LOL of EH media through them. I nearly passed out from shock.
 
Soup Nazi said:
Send em! We dont and never have charged for cleaning and resetting opening pressures.
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Does this stand true if one has a set of your injectors they bought used??

What is involved and what does it cost have them converted??
 
zstroken said:
If the line is not empty, diesel is considered a non compressible. So if the line is full of fuel, your not having an increased volume to fill, your injector is still taking the same CC, so your still pumping the same CC into the line/injector. Am I looking at this all wrong?
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Actually when you're talking about thousands of PSI of pressure diesel fuel is slightly compressible. It would make sense a larger ID injector line holds more volume of fuel, and if you put it under the same PSI as the fuel in a smaller line the volume difference would be greater. . . that is where your timing is affected.

Also there are a number of white papers floating around discussing the changes in injection timing with different biodiesel and vegetable fuels because each one has a different rate of compressibility.
 
Don,

Any Idea how much timming I can run with a P pumped 24v with mach 6s. Ron Is going to let me try his out. I havent been to happy with the few injectors I have tried out, but Ron says yours are the only ones to run.
 
Anyone know the difference in timing of using an injector set for a VP and an injectore set for a p7100?????????????????????
 
No and $750 respectively...

Therefore my injectors have not been reset.
 
Soup Nazi said:
Why the fuss over DV holders? I see people buying modded DV holders from vendors who open the holes up. Why? Do they think the orifice in the holder is too small?

For the record we opened up some holders 7-8 years ago. What happened? About nothing. Anyone know why?

Buying modded DV holders is a waste of money. Well, maybe 20 HP if you get the sizing right and flow equal, but one cant get the flow equal between the holders without reverse Extrude Honing and balancing of the holder. I have a sinking feeling the sellers of this stuff dont even know how they work. We figured it out after pushing about 5 cubic tons LOL of EH media through them. I nearly passed out from shock.
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Don, would it be cheaper to buy your stixs already setup for 24v P-pump versus sending in VP M6's and turning them in 24V P-pump stixs.

Its close to 2k total for the latter way. I was thinking of getting 6's turned into 7+'s. That'd be close to 2500?
 
I talked to a guy who has built injectors for years for the diesel coummunity I told him about this new thing were they take a 12v injector spring and mod it to fit a 24v injector so it acts like a 12v injector for a ppump 24v app , He laughed for a sec and said hmm ok lets see so he took them out and saw there was a little difference but why so much to do this and its really not needed . He said he would have around 50$ in labor/parts but would charge 700+ like the rest
 
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