dieselbeef
dick doggin
how does it affect the lifespan of the vp being 10% higher pressures
Vp44 Injector Pop Pressure theory and testing
- Thread starter me78569
- Start date
Bosch spec says 4500 psi pop +- 250 psi. Which is 293 bar - 327 bar as acceptible range.
Given that peak pressure is well over 1400 bar, I dont see how an extra few bar of pop really matters when we think of vp44 wear. In my mind it's kinda like saying boost blows head gaskets...but maybe I am wrong.
Given that peak pressure is well over 1400 bar, I dont see how an extra few bar of pop really matters when we think of vp44 wear. In my mind it's kinda like saying boost blows head gaskets...but maybe I am wrong.
Last edited:
I dont see it causing extra wear,
Consider that pop happens and pressure increases 4.5 fold if using stock bar, if using 350 bar it increases 4 fold to peak pressure.
I dont see how an extra %3 of pop pressure, compared to peak pressure, hurts anything. seems insignificant. The pump is going to push beyond that pop pressure EVERY time an injection stroke happens.
We can think that maybe that extra 40 bar causes too much resistance off the bat, but again I just don't see it. the vp stroke will outflow the nozzle flow until injector size is too big to care about these things. Regardless of pop pressure the pump is having to push against the resistance of the system at far higher pressures than 310 or 350 bar.
seat of the nozzle maybe, but again the nozzle sees far higher pressures.
I promise that extra pop is far less stressful on the pump as a whole than wiretap is, and guys still use wiretap like it is going out of style. Remember guys running wiretap are pushing the fueling solenoid duty cycle ~%30 beyond what it is rated for......Different components yes, but if we are talking about "hard on the pump" lets at least consider what the standard is for abuse on a VP44.
Consider that pop happens and pressure increases 4.5 fold if using stock bar, if using 350 bar it increases 4 fold to peak pressure.
I dont see how an extra %3 of pop pressure, compared to peak pressure, hurts anything. seems insignificant. The pump is going to push beyond that pop pressure EVERY time an injection stroke happens.
We can think that maybe that extra 40 bar causes too much resistance off the bat, but again I just don't see it. the vp stroke will outflow the nozzle flow until injector size is too big to care about these things. Regardless of pop pressure the pump is having to push against the resistance of the system at far higher pressures than 310 or 350 bar.
seat of the nozzle maybe, but again the nozzle sees far higher pressures.
I promise that extra pop is far less stressful on the pump as a whole than wiretap is, and guys still use wiretap like it is going out of style. Remember guys running wiretap are pushing the fueling solenoid duty cycle ~%30 beyond what it is rated for......Different components yes, but if we are talking about "hard on the pump" lets at least consider what the standard is for abuse on a VP44.
Last edited:
Signature600
THA MAN!
What year is this?
Chris
Chris
To be fair 340 is only about 4% over spec and that's before it settles down...
And overall pressure created by the pump will hardly after affected.. The pressure continues to build after pop it doesn't stop in its tracks at set pop pressure
The V2 tuning makes it worlds easier to run clean with big injectors. no real breakthrough just someone put enough effort into the code to give the fueling control to the user rather than canned tunes. Framework is still the same, methods of altering fueling are the same etc etc etc.
Even with the 305 bar 7 x .012 I have now I can pass emissions which consist of a lug down test with a limit of %30 opacity at 55, 45, and 35 mph.
But what this is all about is if it can be "better". If no one ever asked if they could make something better we would all be walking everywhere. They really are simple questions... what are the perks? What are the downfalls?
Opinions are good, word of mouth is good, work from the builders themselves is good, but I have not see any data prior to this about what happens with bumping pop pressure or reducing pop pressure. Is there a dyno graph showing less power / more power? Does anyone have any opactiy data? track times? Anything? I would love to see any of that, really would. More data is good.
Why is a good thing to ask. The more we know the better. I want to know why reducing pop resolves issues with stalling when put in gear? The logging I take shows the ecm actually has to work less hard to manage idle state with 330 bar with 305 bar. Why? I dont know I would love to know. Why doesn't my truck have stalling issues? The other guy logging had it at 365 but now has none at 330 bar. Whats the difference between us and the other guys with stalling issues?
Last edited:
^^ exactly! Still from all the nay sayers and negative Nancys they're has been little to no decent input, any figures or data, any proof of anything..just a whole bunch of why do that? ..Don't waste your time.. Someone tried it years ago and failed.. I heard that doesn't work... And so on... Why is everyone so against making a good thing better. Why can no one stop and actually put some thought into it? Maybe this has all been done, as some ppl in the know claim, but that's all there is..claims. No data anywhere...
gives me something to mess with. I dont recommend other guys do it unless they are bored as well.
Smokem
Turbler
Connecticut opacity test with a 12v and 5x0.022" VCO injector.
Stalling issues seem intermittent, some worse than others, I've never found a consistent explanation.
As for dyno results it's pretty simple, if you were not involved and did not carry any of the financial burden, don't expect to see the results for free.
I've had several sets of injectors from different companies using the same brand of nozzles sent to me with excessive seat wear considering the mileage, this is irreversible and increasing opening pressure isn't going to make them last longer. Maybe it will help clean up smoke as you have seen, but I only see it as a temporary band-aid, the case hardening in the seat area is not sufficient for extended wear life.
Stalling issues seem intermittent, some worse than others, I've never found a consistent explanation.
As for dyno results it's pretty simple, if you were not involved and did not carry any of the financial burden, don't expect to see the results for free.
I've had several sets of injectors from different companies using the same brand of nozzles sent to me with excessive seat wear considering the mileage, this is irreversible and increasing opening pressure isn't going to make them last longer. Maybe it will help clean up smoke as you have seen, but I only see it as a temporary band-aid, the case hardening in the seat area is not sufficient for extended wear life.
I don't feel entitled to have you share info if you dont like, there was no info out there so I asked and then started to datalog as best as I can.
Your knowledge is your livelyhood, thats fine. Its not an attack on you for not sharing, just that I couldn't find anything. I do applogize if it came off otherwise.
as always good info.
That opacity test is vastly different than ours.
This was with 7 x .009's on an emissions tune before I knew how they ran the test. I think I hit %70 duration. Datalog to show the process we go through here.
I am curious how the 7 x .012's do on power vs opacity.
It is reasonable to assume that it wil. how much I dont know. Another reason why I dont suggest guys do it unless they are bored.
Your knowledge is your livelyhood, thats fine. Its not an attack on you for not sharing, just that I couldn't find anything. I do applogize if it came off otherwise.
as always good info.
That opacity test is vastly different than ours.
This was with 7 x .009's on an emissions tune before I knew how they ran the test. I think I hit %70 duration. Datalog to show the process we go through here.
I am curious how the 7 x .012's do on power vs opacity.
It is reasonable to assume that it wil. how much I dont know. Another reason why I dont suggest guys do it unless they are bored.
Last edited:
Smokem
Turbler
I assumed the opacity testing would be quite different, but the orifice sizing was also quite different.
Regarding the impact on power, it is hard to compare since our testing is done at full load on a negative sweep, this style of testing will not show part throttle or lower RPM differences. I have seen a few instances where increased opening pressure helped reduce low engine speed smoke, however we found that a higher quality nozzle was a better overall solution to the problem.
I have seen better results from tailoring the specifics to match the end user's goals rather than increase the seat pressure on a production part.
Regarding the impact on power, it is hard to compare since our testing is done at full load on a negative sweep, this style of testing will not show part throttle or lower RPM differences. I have seen a few instances where increased opening pressure helped reduce low engine speed smoke, however we found that a higher quality nozzle was a better overall solution to the problem.
I have seen better results from tailoring the specifics to match the end user's goals rather than increase the seat pressure on a production part.
That's pretty good info... Now really what would be the downfall of combining the 2. High quality parts and craftsmanship, along with even slightly higher pop pressure? Say pushing the limits of Bosch spec at 325-330 bar? Seems like you would be in the realm of safe, and have the best of both worlds creating very low smoke and heat with the most power.... I mean honestly all of our findings so far are pointing towards 330+/- 10 bar (kind of a sliding scale with nozzle size) being the best fit, granted all of us are early on yet.
dieselbeef
dick doggin
being the ignorant one here..would not bosch have done any kind of this research to reach a recommended pop pressure?
also I think the statement was made that press builds beyond pop press by the vp..help me to understand that if the inj pops off..isn't the press releasing?
cuz im really just not following most of this for some reason idk
also I think the statement was made that press builds beyond pop press by the vp..help me to understand that if the inj pops off..isn't the press releasing?
cuz im really just not following most of this for some reason idk
@smokem
I wasn't meaning it to be a direct compare on the opacity, just showing what process they took my truck through for emissions and the only time I ever get a dyno number. I am semi scared for the test this year, I fear the lug down will eat my driveline if I run the tune I have now and the injectors I have now.
I keep thinking about that set of 8 x .010's you talked about before.
Bosch did they spec'd 293 bar up to 327 bar in the documents I can find. Anything in that range is " ok by them" apparently the 330 bar I liked so much was just outside the spec from bosch.
The vp stroke will outflow the nozzle so pop happens at say 310 bar, but the vp stroke continues to push fuel faster than the nozzle can flow it. Peak pressure is ~1400 bar on the stroke at WOT. Remember that on a stock truck %70 of the fuel returns back to the tank.
I wasn't meaning it to be a direct compare on the opacity, just showing what process they took my truck through for emissions and the only time I ever get a dyno number. I am semi scared for the test this year, I fear the lug down will eat my driveline if I run the tune I have now and the injectors I have now.
I keep thinking about that set of 8 x .010's you talked about before.
Bosch did they spec'd 293 bar up to 327 bar in the documents I can find. Anything in that range is " ok by them" apparently the 330 bar I liked so much was just outside the spec from bosch.
The vp stroke will outflow the nozzle so pop happens at say 310 bar, but the vp stroke continues to push fuel faster than the nozzle can flow it. Peak pressure is ~1400 bar on the stroke at WOT. Remember that on a stock truck %70 of the fuel returns back to the tank.
Last edited:
dieselbeef
dick doggin
so bosch never used any inj in a cummins with a vp except the stock ones that cam on my truck? huh...
stick with a vco not an sac and the diff will be more noticeable than pop press differences...
stick with a vco not an sac and the diff will be more noticeable than pop press differences...