IPR DC%??

superstroker99 · Aug 30, 2013

My truck is dropping pressure on the HPOP side. Makes about 2400psi at 60% then begans to loose PSI as rpms continue. Im sure my pump is being for about all its worth. My miss understanding is why my DC is stopping at 60% why wont it ramp just that little more out say 80-85%??

Andrew · Aug 30, 2013

Stock or with tunes?

superstroker99 · Aug 30, 2013

tuned by a by a buddy of mine

ken6881 · Aug 30, 2013

What is he commanding as far as Icp goes? And yeah you should be able to get more duty cycle.

mandkole · Aug 30, 2013

max command is 65%

MossBack · Aug 30, 2013

Ever wonder how the backing plate pops off the back and breaks the snap ring ?

Well dead heading any hydraulic pump will cause a failure. So if the ipr completely blocked it off and had no flow you will be replacing pumps.

JD3020 · Aug 31, 2013

MossBack said:
Ever wonder how the backing plate pops off the back and breaks the snap ring ?

Well dead heading any hydraulic pump will cause a failure. So if the ipr completely blocked it off and had no flow you will be replacing pumps.

I'm far from a hydraulics expert, but that idea doesn't seem to apply here. The injectors are using more oil than the HPOP can put out, as shown by the high DC and falling ICP. Its not like your shutting off all the flow, you could probably completely block off the IPR on this truck at heavy throttle and still not maintain ICP.

FWIW on my 2's with Matt's tunes i'd see 80+% DC, but honestly after about 60-65% ICP didn't seem to do much, usually dropped to 1400psi. :fustrate: But i've been told the IPR is pretty much close around 60%.

MossBack · Aug 31, 2013

What I was trying to explain is that while tuning plays a huge part in the role of ipr dc% and icp output. The hydraulic ( mechanical ) aspect is that the pump won't put out anymore icp at XX% vs 100% and the fact that the pump mechanically is limited to its output. So it won't do more if demanded 100% then 60-80.

I have seen the guts of expensive axial rotary pumps because of maxed out swash plate adjustments as well as other flawed diagnosing and repair of hydraulics. So I applied my opinion to what seems logical of the Bosch pump popping off the back plate and if the ipr could max out or dead head the pump I could see that happening. although I believe the ipr does have a internal relief as well as the spitter from each injector to allow return.

backwoodsboy · Aug 31, 2013

JD3020 said:
I'm far from a hydraulics expert, but that idea doesn't seem to apply here. The injectors are using more oil than the HPOP can put out, as shown by the high DC and falling ICP. Its not like your shutting off all the flow, you could probably completely block off the IPR on this truck at heavy throttle and still not maintain ICP.

FWIW on my 2's with Matt's tunes i'd see 80+% DC, but honestly after about 60-65% ICP didn't seem to do much, usually dropped to 1400psi. :fustrate: But i've been told the IPR is pretty much close around 60%.

Issue is that after roughly 50% DC the efficiency of the IPR as a flow control device is diminished to the point where it's basically useless. After that point the oil is fighting too many other restrictions for the IPR to be an efficient flow control device.

superstroker99 · Sep 1, 2013

Ok well I understand now that clears it up. looks like its time for a GEN3

Chvyrkr · Sep 1, 2013

The IPR also saturates like a mofo above 60%... Meaning that it doesn't reverse as quick as it ought to when you let off the throttle.

Results in your truck chugging and sputtering when you back out of the throttle. I'm sure anyone that knows their truck in a certain tune was netting high IPR% know's what I'm talking about.

ken6881 · Sep 1, 2013

superstroker99 said:
Ok well I understand now that clears it up. looks like its time for a GEN3

How well will a gen 3 work on top of a weak hpop

superstroker99 · Sep 2, 2013

well im gonna replace the bad pump with a reman stocker

Powerstroke Racer · Sep 2, 2013

Chvyrkr said:
The IPR also saturates like a mofo above 60%... Meaning that it doesn't reverse as quick as it ought to when you let off the throttle.

Results in your truck chugging and sputtering when you back out of the throttle. I'm sure anyone that knows their truck in a certain tune was netting high IPR% know's what I'm talking about.

So you are saying the magnetic field stays energized after the throttle is let off???

DocBar · Sep 2, 2013

Powerstroke Racer said:
So you are saying the magnetic field stays energized after the throttle is let off???

I think he's saying that the saturation reduces the resolution of the signal and will not be accurate, leading to improper signals. It's not that the magnetic field stays energized, but that it takes a period of time for the saturation of the coil to bleed off and give an accurate reading. This happens quite often in current transformers that are improperly sized or are subjected to abnormal conditions.

Powerstroke Racer · Sep 2, 2013

DocBar said:
I think he's saying that the saturation reduces the resolution of the signal and will not be accurate, leading to improper signals. It's not that the magnetic field stays energized, but that it takes a period of time for the saturation of the coil to bleed off and give an accurate reading. This happens quite often in current transformers that are improperly sized or are subjected to abnormal conditions.

I have called for 100% duty cycles and never experienced what he posted.

DocBar · Sep 2, 2013

Powerstroke Racer said:
I have called for 100% duty cycles and never experienced what he posted.

OK. I'm using my own real world experience in electrical testing and commissioning of electrical systems. I'm not saying I'm right, I'm saying I've seen what he's talking about in real world situations involving electric coils, namely current transformers, solenoids and coils.
An over-saturated coil will give delayed feedback, resulting on poor performance.