Maximum ICP: "The reality"

TARM

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We have all seen and many here been party to the max ICP discussions ( and b!tch feasts). I am not looking for what just any person thinks ICP can be run to and not having floating poppets. IMO the people that know for sure what pressures injectors hold to at given ICP before poppets fail to seal are those that have and or actually use flow benches. To me this means injector BUILDERS and a few others with access. Any person that has access to and has done first hand testing on injectors with specific testing of the max ICP where poppets lift IMO would be qualified to give an answer. But in general who better to tell you what their injectors can handle than the guys that actual build them.

I want to qualify this with saying I know each set of injectors in fact each injector has a different point at which the poppet wills start to crack open. What I am looking for is the given safe limit and what those testing have found to be actual numbers on average. Then what has been seen at both extremes.

I was going to include those that had also done track times or even dyno runs. The issue with those from doing some reading is there are just way to many variables even forgetting the ones of just the devices themselves and the environmental factors. But the effects of the tuning itself can have an issue. Have a engine set up running a bit to much fuel and then raise ICP where the poppet floating may reduce fuel can show a HP gain from the actual reduction is fueling caused by the cracked open poppet. I have also seen it mentioned that Dyno runs being so short may not see the effects in the few seconds where a full strip run would. But either of these can be effected by the tuning so I threw those out. Dynos may have some good data but it would live tuning changes while being on the dyno etc to ensure some other factor is not the cause of the changes.

This is speaking of injectors that are commercially available to a typical user even if by request. Not any one offs creations. I know the kind of crazy things Jason, Dave, Nate and others can make. ;)


As a refresher and in general a very informative Max ICP thread to bring anyone that wants needs to be brought up to speed on the subject:

It was started by Tom S over on PSN before the days of PSA back in 2009. It was kept civil and some good info was put forth. I recommend for those with basic questions read it and do so carefully. There are some short and long posts that give very good answers to various things. Read the whole thing.

Maximum ICP Thread



I have put forth a number of questions through out as well as farther down in this post. These were born from reading all the threads I could find on the subject (yes I was bored, with way to much time on my hands) :( I am pathetic, I know. :lookaround:

I felt these questions might help generate thought, discussion, and I personally would like answers to them.

I have not done a completely exhaustive search but gone thru a really good number of threads here and PSN. Here is what I have found:

It seemed in your average group of end users the number most seem and posted when asked is 3200 psi as being the typical max. Where did this number ever come from anyways? Its not from builders, nor is it standard format flow bench data sheets. Not OEM PCM data. So where?

When I look to what has been stated by builder and those who have tested on the bench the limit is 2800-2900 with some being good to 3000psi.

The only numbers I have seen ever mentioned above the 3200 comes only from those that neither are injector builders nor flow bench users. This is based on as far as I can tell from what I know of their history and what has been posted. Many times this might be one in the same.

At the same time every flow bench flow data sheet I have seen as it seems to be the general format has flow data with ICP from 500 up to 3000 PSI. Does this not mean that every set of injectors that is accompanied by a flow data sheet that shows for fuel per time @ 3000 ICP should be expected to be OK to run at that level? The table could show if there was an issue with a drop on flow amount if the table did not jump from 2500 to 3000 but instead as you reach 2800 the tested increments drop to 100psi. This seems to be at somewhat of a conflict with info I found posted.

What good is flow data @ 3000psi if all you can pull is 2850 ICP or whatever?

Would it not be good for the data sheet to show ICP until there is a drop of one injector? (100psi increments once 2800 is reached)

How much if any decline in holding pressure do these injectors typically see? 50K 100K 150K etc..... Something that is holding new may not being holding anymore a year later if set at the ragged edge. Springs decline in tension with each and every compression cycle no matter how well made. Its small but over time there should be a noticeable trend. (explains why Charles mentions pulling it back at least 100 psi from what he found the limit to be.) These are held by springs right.

Now here is the thing. Most of the real informative threads on this happened years ago. 2009 had a number of good ones. What I want to know is has any of this changed at all with any new mods or changes made in the field of building injectors etc...


So this is not about EXTREME ICP unless that is something that has been from modifications/changes made in the last couple years by injector builder. What this is about is where is the line from testing and has anything at all changed since 5 years ago in this area?

Further is anything on the horizon dealing with this in the injector world? (HRT, Nate, Swamps, Casserly, Jim anyone?)


I think if we are seeing higher ICPs being called for in our tuning and we have the builders giving first had accounts of issues at pressures this high some tuning adjustments may be in order.

If anyone want to make any constructive comments or has questions on the subject please feel free. Just make sure it is actually constructive. Any posts looking to derail this into a Extreme ICP vs everyone else I will ask the mods now, to clean it up as they see fit.

If you are just going to post that "I run this much ICP and I see no HP loss or my stuff runs good" do not bother. That's not what this thread is about. Further dyno results or whatever showing no power loss doesn't really tell the story either as the point of a maximum ICP is to GAIN power If its the same why stress things for no benefit.

If a person has more capacity that the amount of fuel he is using and its enough a short dyno run could possibly allow it to still have enough fuel capacity for what is being called for. Say a 400cc/200% where max fuel called for is 230cc. Is this not a possible way to get a better dyno peak vs real world usable peak power output?
 

Dieselboy.

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Might be a newbie question but I've always wondered, why can't we demand higher icp pressure. Say 4000 psi. Would that not increase injection pressure ? With the advances in injector technology can't we design an injector to handle 4k psi at wot. Even injecting the same cc's of fuel would it not increase the "burn rate"
 

TARM

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Go read that thread I linked to in the middle. It will answer your questions on most things ICP / injection related. What it comes down to is yes it would but our injectors are not designed to handle that. That is one of the major if not the major change in the 6.0 injector design that allows them to hit those higher RPMs and HP rates. They can hit 4K and that then allows them to put not only more but better atomized fuel in per crank window.
 

Chvyrkr

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I think another thing to consider is how oil reacts and the result of runnin it at those pressures in our HPOS's.

IIRC from other discussion on it, aeration in a 7.3 gets worse and worse the higher you get.
 

TARM

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Well that certainly makes sense. But that is something that could be dealt with if we actually had injectors that could handle and positively use that pressure. But as its not usable all we end up with that much more shearing and aeration.


I have dealt a good deal with spring manf tech from the firearms field. While springs can be made to hold a certain tension range as far as I know there is no way to eliminate the loss of tension no matter however slight it maybe that occurs with each and every compression cycle. This is why I am very interested in what kind of duty life we are looking at with these poppet springs and the rate of tension loss. The general rule of thumb we always went by was once a 10% loss in tension was reached they were considered at the end of their duty life. I won't bore you with all the techno garble of spring manf tech beyond that.

So if we say either thru bench testing or thru dyno work as Charles has laid out in the linked thread and find were we are starting to have the poppet no longer sealing and say back off 100 psi how many miles roughly before we should come back and reexamine out setting? 10K 20K 50K 100K what?
 
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I'm sure I'm no help....

QUESTION: How much pressure can I run with my pump and injectors?

ANSWER: The factory designed our HEUI injectors in our 7.3L Powerstrokes to run efficiently at approximately 3000 psi. We don't recommend running pressures over 3200 to 3300 psi. There are no significant power gains by ramping pressures over 3400 psi regardless of what you hear out there. All you will do is create unwanted stress on your injectors and injection system components.

http://www.stealthpumps.com/SI_Stealth_Pump_Facts_vs_Myths.html

I been told this site is supposed to be up dated with a bunch of facts about the HPOP system in the very near future... maybe now is the time to get it all out...
 

TARM

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Thanks Ron

Maybe that is where the 3200 came from. The issue is this is the limits set on a HPOP by a hpop builder not injectors. The HPOP itself is not the real issue its the injectors.

Dave of Swamps gave a really good explanation of the limits of the oil side of injectors in a post somewhere. I need to find it as I think it maybe germane to this discussion. I'll have to read it over to be sure. Will try to find it when I get back in the condo.
 

TARM

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I do not think there is any question that extreme ICP does not work and is likley counter productive at least that is my opinion. I am more interested in some of the other areas of it.
 

JAP

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I do not think there is any question that extreme ICP does not work and is likley counter productive at least that is my opinion. I am more interested in some of the other areas of it.

What other areas? Just curious.

It seems obvious to me... Higher ICP would be an awesome thing for the 7.3, if an injector were built to handle it.

A 4:1 ratio injector would probably do pretty awesome if the intensifier could see 4,000 psi. But that is common knowledge by now.
 

TARM

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Things like how fast does the poppet spring loose tension. What exactly is the ICP most injector makers recommend? Is it worth having your injector tested to see what level it does start to float by the builder then you can set your ICP 100 psi or some number lower. But then this brings us back to how fast does the spring lose tension. You do not want to set it to say 3100 and then 10-20K miles later you have floating poppets.

Then maybe tie these questions of ICP into something that Bill has posted about a few times in his theory of what causes a drop in ICP pressure or a rise in DC when you exceed a given PW with a correlating drop in power. This deals with in part the IDM signal.
 

Big Bore

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Seems to me that reading the earlier comments concerning actual nozzle pressure and cutting of the tip that the injector is getting all the pressure it would ever need. Isn't the issue that we cant empty and fill the injector fast enough, not nozzle pressure?
 

TARM

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Big Bore what comments about actual nozzle pressure and cutting of the tip etc? I do not see where this has been posted about in this thread. Could you link to it if its in another thread. Thanks.
 

TARM

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Here is a great post by Dave that explained exactly what is happening mechanically as a injector fired. I really think this should be a sticky somewhere as I think myself included many do not know how an injector works or do not know it by heart.

Without getting tooooo explicit.

From a purely mechanical standpoint, what happens when the injector fires?

In this order:

Armature plate lifts (simultaneously lifting the poppet valve)

HPOil pressure begins, begins, begins, begins, begins, begins, begins to transfer its pressure through the poppet valve.

now...stop...freezeframe.

nothing internally has even begun to MOVE inside the injector...there has been no FLOW through any oil or fuel side components OR potential restrictions.

WHY?

The nozzle, or more specifically, the spring holding the nozzle needle SHUT (typically requiring @ 2750psi on stock injectors to begin to LIFT) is still closed...I mean we are talking tenths of ms here...but bear with me.

The nozzle needle will not begin to lift until (use your MATH here, as there is no flow, no restrictions to change the dynamically changing volumes, due to part movement, within the injector)..

on an hybrid, "5:1" injector, with a 2750 "pop" nozzle...there actually has to be at least 550psi (2750 divided by "5") of OIL pressure transferred through the poppet ..so the pressure begins to be transferred through the poppet ONTO the intensifier piston which will then transfer ITS' pressure "5:1" to the plunger...100, 200, 300psi, 400, 549psi(still...nothing has moved)

*crack* the nozzle needle now lifts exactly at 550psi HPOil psi (2750 fuel psi at the nozzle)

now sh!t starts moving...since fuel is FLOWING out of the nozzle.

the intensifier piston starts to stroke downward (simultaneously moving the plunger against the fuel)...creating MORE SPACE (more volume to be filled by HPOil) above the intensifier piston, so we have a pressure drop across the poppet valve...

On one side of the poppet valve...we have ALL THE OIL IN THE WORLD...oil rails FULL of "extreme ICP"

on the OTHER side of the poppet valve...the side that is constantly/quickly increasing in volume (because the IP is "falling away") we have less pressure...this is not easily measured directly, but my previous post is 'proof'.

OK...so oil is trying, DYING to get through the poppet valve...trying to 'keep up' with the ever increasing space created by the void left behind as the IP moves down...more pressure drop....all the while, you have your "extreme ICP" just hanging the "F" out in your high dollar pumps, and within the oil rails in the heads.

starting to see what's happening?

now, put a BIG ASSSSSS nozzle on that injector...ya know...like the 200% EDM's that are available...hell, we'll make it "best case" scenario...and keep the VOP of that nozzle at factory levels...at 2750psi "pop".

now, all this happens again...now, with an even LARGER nozzle like we have now...all the internal parts are going to move STUUUUPPPPID fast...as that big ass nozzle offers no real restriction to flow...so we create an even LARGER pressure drop across the poppet...

(at the nozzle) injection pressure is horrible because the F'n oil can't "keep up" with the IP dropping faster than the oil can get in...

NOW, let's make it a B-code!!!! 40% larger oil side to fill...same oil restriction at the same ol poppet valve...

now...

I hope anyone & everyone here involved in this thread can agree...HPOil is THE key to making good power with the HEUI Power Stroke injectors. Doesn't matter if you have 100cc's or 1000cc's...if you don't have "good ICP" the truck is a turd...smokey...inefficient...

now, what happened when you put that twin HPOP on your truck? Bam!

Instant throttle response...much more crisp, much cleaner burn...much more efficient.

I could get into all kinds of crap about 'instant' HPOil pump output...and how THAT can affect oil 'flow' through the poppet...but hopefully my video illustrates that a 300cc B-code injector needs to move (6 x 300mm^3) 1800mm^3's of oil THROUGH the poppet in UNDER 2ms....every single injection event...every single injector...

a hybrid only has to move (5 x 300), and an A-code (7 x 300)...see a pattern here?

Volume of oil per time is the key.

know wonder we have so many quitters ...very, very few people understand the F'n HEUI injector...and none are as committed to it as us. Period.

I'll stop now, and clarify if needed.

but...hybrids use LESS HPOil per volume of fuel delivered than ANY type of injector out there...and the OIL is the key to making power with HEUI's...


always has been.


Edited to add. He just made this post which gets more specific of what is happening with the poppet.

since I never seem to get over to this site as frequently as in the past...

I'll try to contribute to this thread as often (& as accurately) as I can.

a couple of points pertaining to the poppet/poppet spring/solenoid, etc...

An injector solenoid has approx 20lbs of pull on the poppet valve(actually pulls on an armature plate...which is directly attached to the poppet valve)..and the solenoid will only be able to have a magnetic pull when it is within @ .010" of the armature... increase the distance b/w the solenoid and the armature...and the magnetic field is weaker...decrease the distance (ie, when the injector is firing, and the magnetic field is stronger)*more on the affects of frequency & signal shape from the IDM later.


the poppet spring is about 3/4" in length...ground square on both ends...with ~0.0625" wire....ie...a pretty small & weak spring...at it's installed height inside the injector body...there is approximately 20lbs of seat load on the poppet (lower) valve seat...

Amazingly... An energized injector solenoid has approx a 20lb 'pull' on the armature plate...at a specified distance...we've been calling this distance between the solenoid and the armature plate...simply "over" for years.

so...

while the ICP pressure is trying to 'blow open' the poppet valve...this same pressure (acting equally on all sides of this valve/top/bottom/etc) is simultaneously trying to keep the poppet 'down'...away from the solenoid...

you could literally remove the spring from the injector...and apply ICP to this valve..and you could lift it up or close it with a fingernail...the little spring merely add's the little extra bit to unbalance the valve to keep it closed/sealed. literally..."fire" the injector without a solenoid in a test bench...by gently lifting and then barely touching the armature back down to close this valve...with a finger.

lift the armature/poppet with your fingernail...the ICP immediately * instantly pushes the poppet to its' upper seat, sealing it firm & tight...and the injector would fire. once.

click. one injection event...

on a properly built injector...no oil should be escaping around the upper seat...and since there is zero "flow" through the injector (oil or fuel side) after this single firing...

there is no extra demand on the oil pump that is supplying this oil pressure/ICP to the injector. The pump is just sitting there humming at its' desired ICP pressure...and the injector is just sitting there static.

so...we just "fired" an injector for what...a couple of thousand milliseconds by now, ..

headed home....be back tomorrow.



Its a shame, as much of all this stuff all ties in together but they are still two systems at work. Another good thread going on is this one Bill just start over on PSN The relation between Injection Pulsewidth and Loss of ICP

You end up having to go digging thru multiple threads and pull posts wading thru all the BS to get a really good understand of how these things really work.
 
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Big Bore

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Big Bore what comments about actual nozzle pressure and cutting of the tip etc? I do not see where this has been posted about in this thread. Could you link to it if its in another thread. Thanks.

You know what, your right lol. I think it is in the PSN discussion you linked. Someone who does water jet cutting brought up the pressures used, and then the pressure ratios were discussed and where the injection pressure is at the nozzle using High ICP and IIRC it was getting real close if not at the cutting pressures and well past CR pressures.
 

TARM

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LOL yep that was IIRC Bill trying to bring injection down to layman's terms. It was in that Maximum ICP thread I linked to.
 

2000wa250

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I am going to resurrect this thread for a simple idea that popped into my head today...

What specfically is different about the spool valve vs the poppet valve? Is it not feasible to modify the 7.3 injectors to use the spool valve from the 6.0 injectors?

Along these same lines of making everything crisper (for lack of a better term), we upgrade fuel supply, we upgrade hpo supply, we upgrade IDM, why do we not upgrade solenoids or poppet springs? It would seem to me that if you put a tad stronger spring in, with a stronger solenoid, wouldnt you be able to have faster response in both directions and solve some of the problem of bleeding pressure off?

I'm assuming that the problem with the spool valves instead of poppet valves results in the fact that we dont have FICM that we have IDM instead... However, would it be something feasible and or beneficial to run 6.0 style injectors in a 7.3 so that we could run ICP up there above the 4000psi level and achieve much higher injection pressure and therefore be able to take advantage of having a more precise injection event, and possibly running lower PW, making the entire system more efficient, and who knows, maybe letting us make power up into higher RPM ranges while still utilizing the HEUI system?
 

Hotrodtractor

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A= 7.3 B=6.0

-9lZ1KLn_16Llyk8e_jkv4pVaWrKM3BzZLDuUp-39tzHBcPfZU.jpg


Spool (not exactly as used in the injectors - but close enough to get the idea)
4.jpg


Poppet
1.jpg


Who says no one is upgrading poppets, springs, solenoids, etc? Just because its not plastered all over the net doesn't mean it hasn't or can't be done. I melted down Nate's flowbench one day testing high ICP..... that was probably late 2008/early 2009.
 

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