Anything new with the p-pump conversion injectors?

shiftycapone said:
I just had my mach 6's pop tested and they came out at 260bar. Funny since they came to me from Don that way, for my truck when it was a vp. Eric at browns told me he thinks they are lowered to help the vp live.
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I've seen them from 240-290BAR, it has nothing to do with helping the VP44 live.
 
I think Don has specified 305 Bar as where vp injectors are set. The pressures fall with time. I'm not sure where my 7's started, but after a little less than a year they were at 260. I checked them recently and they are down to 245. I have been seeing more smoke at idle and slight throttle too. I don't know if the two are related, but they do seem to be.
 
RonA said:
I think Don has specified 305 Bar as where vp injectors are set. The pressures fall with time. I'm not sure where my 7's started, but after a little less than a year they were at 260. I checked them recently and they are down to 245. I have been seeing more smoke at idle and slight throttle too. I don't know if the two are related, but they do seem to be.
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My machs have maybe 10k on them, so I guess it could just be a normal "wearing" of the spring.
 
Smokem said:
You will not see a drop of 40BAR with "normal" wear.
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I didn't think I should, but after hearing Ron have some similar results it made me think. I don't feel that I put anymore wear on injectors than any other person. Manufacturing issues?
 
shiftycapone said:
I didn't think I should, but after hearing Ron have some similar results it made me think. I don't feel that I put anymore wear on injectors than any other person. Manufacturing issues?
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Mine didn't start out any where near 305bar. Probably around 4000psi if i was to guess. There is always the possibility that the gauges are different. I have thought about checking my tester against a couple others to see how the readings compare.
 
im planning on going with a scheid 13mm ppump soon ima keep my mach 7s there was a truck with mach 7s with 24v pop pres that had a columbus built 12mm pump that made 800hp on fuel with i believe 62 over 88 twins turbos
 
I've seen many 24v injectors, from a few different companies have opening pressures all over the place, and often quite a bit too low.
 
Smokem said:
I've seen many 24v injectors, from a few different companies have opening pressures all over the place, and often quite a bit too low.
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It was explained to me that lowering the pop pres to much on VP inj will lose the desired atomization of fuel, however the higher (than a 12v) opening pres will shorten the duration of the injection event. So other than a conversion injector we are stuck with what we have, but is it nessicary in a competition application only? What other options are there?
 
shiftycapone said:
Please elaborate on what the reason for lowering the pressure is in a vp injector to the point where it gets into p-pump opening pressures?
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Price the shims for a stepped nozzle holder. So much easier to just put nozzles on and send them out the door.
 
Smokem said:
Price the shims for a stepped nozzle holder. So much easier to just put nozzles on and send them out the door.
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I set the lathe up to machine shims first. Then test them all and figure out what size shim they are going to need. Then make a shim, assemble and test the injector till it's where I want and then move on to the next. I don't blame some places for cutting corners. I wouldn't want to do it for money, but i don't mind taking the time to keep mine where they need to be.

Ron
 
I've seen quite a few interesting things.... using zinc washers as shims, and still having them set between 240 and 280 in the same set of injectors.
 
985cumminslover said:
im planning on going with a scheid 13mm ppump soon ima keep my mach 7s there was a truck with mach 7s with 24v pop pres that had a columbus built 12mm pump that made 800hp on fuel with i believe 62 over 88 twins turbos
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That sounds familiar...

Personally I would LOVE some injectors built just for the application (tighter spray angle too), however I, like most just don't have the funds to get any (especially when talking about a new product). So for now my standard, probably worn out Mach 7's will have to do. Unless I could sell a kidney for some new sticks.
 
SHughes said:
That sounds familiar...

Personally I would LOVE some injectors built just for the application (tighter spray angle too), however I, like most just don't have the funds to get any (especially when talking about a new product). So for now my standard, probably worn out Mach 7's will have to do. Unless I could sell a kidney for some new sticks.
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You ran a 13mm? I had always thought it was a 12mm?

Scott what size is your primary's compressor? Think you said 83-85 one time not positive and can't find the post.
 
You guys are making me think I need to check my pressures. Its been a lil smokey under light acceleration, more than usual.

What's a good psi for a p pump conversion?
 
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