VP Dynamic Timing Vs. Advancing

Another thing I would like to mention is fuel pressure. What are you guys running? I am at 24psi idle.
 
Hey, just a thought. If you increase POP pressure, you will get better atomization and a more complete burn correct. However, increasing the pop pressure will retard injection timing. However, with mechanical advance you could compensate for that, possibly getting the best of both worlds. Does anybody have an idea of how much pressure the VP can handle before you start doing damage to it? It may be close to its limit, but I'm really not sure.

IIRC- stock pop pressure is 300bar, and I believe I have read that SDX sets their injectors to 310bar. Would it be possible to set it higher and then advance the pump so that there isn't any total timing loss?
Sean
 
sstockton said:
Hey, just a thought. If you increase POP pressure, you will get better atomization and a more complete burn correct. However, increasing the pop pressure will retard injection timing. However, with mechanical advance you could compensate for that, possibly getting the best of both worlds. Does anybody have an idea of how much pressure the VP can handle before you start doing damage to it? It may be close to its limit, but I'm really not sure.

IIRC- stock pop pressure is 300bar, and I believe I have read that SDX sets their injectors to 310bar. Would it be possible to set it higher and then advance the pump so that there isn't any total timing loss?
Sean
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I've heard numerous opinions on the vp pressures. I think anything over 24 is pushing it, but then I read threads where guys say they run 30psi. Too many opinions on that subject without hard evidence. My mach injectors are supposedly 280 bar [atleast thats what I've been told].
 
So I have a bd vp that is off right now due to a seized rotor. I am wondering if I should advance one gear when I go to do this. My question is will I get any benifit with this only have a edge juice ATT it doesn't seem to fuel very high. Like 2600 rpm it falls on it's face. But I can get the revs up to 3200-3300
 
Pgdsm said:
So I have a bd vp that is off right now due to a seized rotor. I am wondering if I should advance one gear when I go to do this. My question is will I get any benifit with this only have a edge juice ATT it doesn't seem to fuel very high. Like 2600 rpm it falls on it's face. But I can get the revs up to 3200-3300
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Do you already have the hot unlock for that edge juice/att?
 
cummins724 said:
You still alive bud! I haven't heard from you in a while. How are those 250's?
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ya i am still alive
Ive just been working a little too much lately. lol
250s are good. i have just been running them on the sc micro so i cant comment on their full potential. ive towed my 24ft box loaded (7k?) and there no hotter than my 125s.
mileage is down a little. i think once i get my adrenaline back i can put some timing in her and ill be back to normal.
 
gotslicks said:
ya i am still alive
Ive just been working a little too much lately. lol
250s are good. i have just been running them on the sc micro so i cant comment on their full potential. ive towed my 24ft box loaded (7k?) and there no hotter than my 125s.
mileage is down a little. i think once i get my adrenaline back i can put some timing in her and ill be back to normal.
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Cool. You should get involved in this thread as well. It never hurts to have big money helping with research.:hehe:
 
Pgdsm said:
So I have a bd vp that is off right now due to a seized rotor. I am wondering if I should advance one gear when I go to do this. My question is will I get any benifit with this only have a edge juice ATT it doesn't seem to fuel very high. Like 2600 rpm it falls on it's face. But I can get the revs up to 3200-3300
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This seems to be a pretty new idea, and hasn't really been discussed much openly prior to this, or at least not to my knowledge. So we really don't know how it affects different trucks. And also how it works with different mods. I'm not sure if you would gain as much running stock injectors. Its worth a shot though, if you aren't happy with the results, it is pretty easy to switch it back.
Sean
 
I dont know why anyone is bothering with this. If it was possible or helped at all Schieds or Haisley or someone would've already done it. $.02





At least thats what's said every time something new is brought up.:bang LOL
Oh, and this is all a waste of time anyway because only a 12v ppump is worth bothering with.:hehe:
 
I called Chip about upgrading my redline to unlimited today. He said "free of charge". We also got into pretty good discussion about the topic of advancing the gear. Chip said "There is nothing to gain because the vp44 will compensate for the mechanical advance". Then he said what I wanted to hear. ....."Unless ofcourse you bypass the ecm by using a Redline box which will totally ignore the ecm". According to him, the truck should run/drive normally when the redline is turned off because the vp will compensate, but turn the redline on & you will have a lowend turd that runs like hell above 2000rpm. LOL
 
Sounds like your cup of tea and with your mass amount of boxes you shouldn't have a problem being able to compensate. LOL
 
sstockton said:
This seems to be a pretty new idea, and hasn't really been discussed much openly prior to this, or at least not to my knowledge. So we really don't know how it affects different trucks. And also how it works with different mods. I'm not sure if you would gain as much running stock injectors. Its worth a shot though, if you aren't happy with the results, it is pretty easy to switch it back.
Sean
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Way back when VP trucks were still being sold new, I know for a fact that a certain diesel head in GA was playing around with the idea, but gave it up as a lost cause. What he was running into was the VP negating the mechanical change electronically. Here's the "but", at the time there were not the number of different modules that are on the market now with different features. Now that the redline box and others that exert more control over the whole enchilada are available, it makes sense to revisit this. Just as stated above, it's not a huge ordeal to change back.
 
BgBlDodge said:
Sounds like your cup of tea and with your mass amount of boxes you shouldn't have a problem being able to compensate. LOL
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Yeah, I'd say that if this is possible, I should have a good chance with all of my odds in my corner.:hehe:
 
I finally got some time to work on my front cover. My buddy gave me this cover & luckily I have a spare engine sitting here for mock up. I cut it & welded a tab on the back so that I can seal it with rtv in the seam. Quick gear adjustments!

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thats the same design in working on but im putting another flange on the outside so i can put a rubber strip inbetween the 2 layers and use it as a seal so i dont have to mess with rtv each time
 
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