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Discussion Starter #1 (Edited)
FWIW, I didn't start this thread, Danny did.



i have big split shots to run

Well, step one complete, you've located the problem with your truck. Step two is getting rid of them or swapping out the P&B assemblies and not thinking different pump setups will have any effect on the issue.

If the system delivers the oil quantity you need to go full stroke plus some reserve capacity, you are all set. And every offering you mentioned does just that with the exception of the single 17* pump.

And the reason 500cc injectors don't work WOS has very little to do with pumps. Reason one is... that's enough fuel per injection event, that if ever injected and burned would throw block, rod and head fragments into low earth orbit. And secondly, it's kind of of hard for any pump setup to empty a 500cc injector (to even get the chance at your burning it and throwing engine parts at people) when the called for injection pulsewidth drops down to the 1 or so ms range. Smokes like a freight train coming up, then just falls on it's face (comparitively) and just cruises on out to the limiter only injecting a fuel quantity around 20% of the full stroke amount more or less depending on a bunch of different factors.

And again, if the thread topic permits:

What is there about a pump setup that determines system pressure other than the volume of oil the setup can deliver vs the volume of oil the system is consuming?

Near as I can tell any setup will produce any pressure you want as long as two requrements are met, that the pump setup is displacing more volume than the injectors are consuming + a buffer to keep the duty cycle within a PCM acceptable range, and that a pressure relief is not blowing open anywhere in the system. The more of a "buffer" in excess oil volume you have, the more responsive the pressure will be, assuming the IPR response settings are not altered.

Now, why you would ever want to push the pressure higher than the emergency relief on the pump is beyond me, but that's another issue, and some people report success with it, so be it.

Regardless of that, I see no reason why this single pump cannot meet people's needs. A big single piston pump is not a new revelation. Swamps has been offering one for years now and I see no reason why this unit from Stealth wouldn't every bit as good considering the amazing leeway in capability that scratch building anything affords.

Supplying oil to these engines is much simpler than all this. You either have enough, or you don't. If you don't, you just increase the displacement of the pump setup until you do...
 

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Re: New Stealth Design

I know Bean stated earlier that he doesn't think there's a need for any more oil than what the current systems provide, but has anyone run into any issues with a big oil set-up not doing enough? I haven't.
 

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Discussion Starter #3
Re: New Stealth Design

I know Bean stated earlier that he doesn't think there's a need for any more oil than what the current systems provide, but has anyone run into any issues with a big oil set-up not doing enough? I haven't.

Not that I am aware of. But... I am also not aware of anyone running dual 17* pumps that does not have their injection pulsewidth systematically cut back by the OEM electronics exactly as needed to keep injection events seperated either.

I see no way around the fact that if this issue is solved, oil volume demanded will increase substantially as injection events remain big enough to empty injectors at increased rpm where they are closer and closer together, meaning more and more oil volume is used per time, or per revolution. And it is downplayed, but at some point the pulses will overlap. At this point the pump will be supplying the demand of two injectors continuously. That is going to take a lot of oil if that kind of injection duration is still producing power.

Time will tell.
 

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Re: New Stealth Design

And it is downplayed, but at some point the pulses will overlap. At this point the pump will be supplying the demand of two injectors continuously.
Why will they be overlapping?
 

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Re: New Stealth Design

Why will they be overlapping?
I would guess over lapping pw's are involved with high rpms? Also as i understand our idm wont allow over lapping pw's? Im thinking more oil will be needed if we can get some more pw. I hate to say it, but im sure charles can explain it. Before anyone jumps my case, he may not make "big" power but imo he might have a good idea or 2.:postwhore2::D:doh:
 

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Re: New Stealth Design

I am thinking along the lines that the poppet spring not being able to shut off the event quickly enough, hence the potential overlap.
 

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Re: New Stealth Design

I would guess over lapping pw's are involved with high rpms? Also as i understand our idm wont allow over lapping pw's? Im thinking more oil will be needed if we can get some more pw. I hate to say it, but im sure charles can explain it. Before anyone jumps my case, he may not make "big" power but imo he might have a good idea or 2.:postwhore2::D:doh:
In the temporary absence of Charles, I'll give it a shot.

Each cylinder fires once for every 2 rotations of the crank. So, only four cylinders will have fired for each rotation of the crank.
Now, when the pulse width (PW) of the injection event is longer than the time between injection events, you have overlapping injections.
For instance (Purely hypothetical and made up numbers):
4000RPM (Not unheard of for good motors) makes for 2000 injection events for a single cylinder per minute. That is 33.3 injection events per cylinder per second, which is .03 sec between injection events for a single cylinder.
Now remember, there are 4 cylinders firing on this single rotation of the crank. The crank takes .015 seconds to make a single rotation, that makes .00375 seconds between the start of injection in consecutive cylinders.
So in this example, if the pulse width of any injection is greater than .00375 sec, the injections will overlap.
 

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Discussion Starter #10
Re: New Stealth Design

That is exactly right. At 4k and 3.75ms of pw you begin overlap. If you think about how long it takes most injectors to empty, you realize that 3.75ms is not a long time. And if you still wanted full power at 4k, you need the injectors empty. Now, a "quicker" injector will be beneficial as well, and I don't expect to run that much pw right on off into the rpm sunset. The dyno will dictate the injector speed and pw I go with. 3.75 or more at 4k might not make power. It might be too much time. I will find out. But the important thing is the ability to decide for yourself if 3.75 more or less makes power. Not being forced into 1 to 2 or so ms or the dreaded .6ish ms by the OEM electronics. I for one would like to see if more pw is beneficial, and to what extent. Then decide for myself where the point is that more pw just equals more pw and not more power.

But, as to the thread topic, if anything near or exceeding overlap is found to be worthwhile at making power, oil demands will exceed the capacity of some of the current systems. I'm sure they have plans to accomodate higher displacement if needed though.

I only mentioned it because the unit in question does list a version with more capacity than most.
 

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Re: New Stealth Design

That is exactly right. At 4k and 3.75ms of pw you begin overlap.
I'll be anxious to see the results of your testing but I really don't think there is going to be a need for the injection to continue beyond 90°. I'd think half that long would be getting close. When does the exhaust valve start to open on these things?
 

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Discussion Starter #12
Re: New Stealth Design

I say, if anyone wants to discuss pw, there should be a new thread. I didn't want to derail this one, just wanted to provide reason behind the potential need for more oil than twice stock.

Haha. Well, since Danny has gone to such great lengths to provide for the topic here :D... I guess I'll try and come up with something to say about it ;)


I guess the first thing to be said would be... what determines the current pw curve? Is it what Ford saw as the optimum injection duration for the rpm range? Unfortunately, no. It has nothing to do with burning diesel fuel, piston position or anything else of that nature. It is simply responding to the built in buffer between injection events provided solely to ensure that the communications signal between PCM and IDM never became unstable. Once you reach a certain rpm (around 26-2800 usually) you start seeing the effects of the buffer in the form of your injection pw getting cut back to retain the integrity of the injection pulse spacing. This is also why you see 7.3 trucks making their power peak in this same basic rpm range independent of turbocharger sizing. It is very hard to make a 7.3 peak any higher than that, and if you do, you are simply creating conditions there better than what were seen at the 26-2800ish range with boost, or nozzles or some other means, even in the face of the fact that the PCM is asking for less.

So. Are we to assume that the limit in stability of the communications signaling just so happens to coincide with the limit in the optimum injection duration for these engines? Or is it more likely that the engine was simply setup for work duty and in this duty a different signaling approach capable of stability with full fuel at engine rpm exceeding the rev limit on any T444-e was simply an unecessary expense that the end-user would not be willing to pay for?

A second issue to be aware of. The successor to the 7.3... the VT365. Does it peak at 26-2800rpm? No, it does not. In the case of the 6oh, the hydraulics control of the injector is blazingly fast. Meaning, a ton of pw is simply not needed to get the injector started. We have a good bit of "lag" time. Unused pw, wasted to the lag in firing the 120+ volts needed, then for the Coil to build a field, then for the field strength to be able to yank the armature up and finally for the high pressure oil to begin flowing across the poppet and onto the intensifier piston at which point we can start the process of actually flowing fuel into the cyinder. On the 6L injector, it's a "spool" valve. Positive electrical on and off. Not spring loaded and very fast. This is why a 6L injector can still empty in less than 2ms whereas our injectors might take 3 or more ms to empty.

The important factor is this. The 6L injector injects less fuel than the 7.3 in stock form. But the 6L being so quick, can still empty even without a lot of pw. This isn't because it's necessarily quick at actually expelling the fuel. It's likely about the same as the 7.3 injector in terms of time to empty the actual fuel itself. But, it does not suffer the lag, and injects fuel for almost all of the called pw, whereas our injectors spend some of that time doing nothing but waiting on the armature to snap up.

So what does this all have to do with power? The 6L can still get all the fuel out at higher rpm because it needs less called pw because it's using it's pw more efficienty than the 7.3L injector is. So, at 2600rpm they're both probably empty. And the 7.3L, having more fuel to deliver, is most likely making more torque at that rpm.... meaning it's got more power as well. Then 2800 rolls around, and things are probably still the same. But what about 3000? Now the 7.3 injector is starting to lose called pw because the PCM is getting into the buffer between injections and cutting back. Whereas the 6L injector is still chugging away empty. Now the 6L isn't down on TQ at compared to the 7.3. What about 3400? Now the 6L is still getting a good bit of fuel out, and the 7.3 is looking very bad off on TQ output....hence power for that rpm. It is at this point that the 6L is making more TQ than the 7.3 by a good margin.

The reason this is important, is that power is work per time. Even though the 6L might not make the peak TQ of the 7.3 because it's got less fuel to burn mainly, it makes it's TQ at a higher rpm.... and is rewarded with more power for that TQ than the 7.3 is. This is also why the 6L produces more total power than the 7.3 even though the 7.3 makes more TQ at peak.

And an important issue to also bare in mind, is the fact that even though the 7.3 makes more TQ than the 6L, intake exhaust and a chip the 6L outruns the 7.3 everytime because it's making 400+hp to the 300+hp of the 7.3

And that, is why pw is important. I think everyone can already see the effects to oil consumption that having full fuel at elevated rpms will create.

I hope that doesn't create anger. It's just the only explanation that makes sense, and correlates to the evidence we see everyday with these things.

As to injector "speed", you all can rest assured that as soon as I get the pw ironed on out I will be doing just as thorough testing on that as well.

That's my input on the topic.
 

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Why not one PCM IDM for 4 (1,2,7,3) injectors and a second PCM IDM for the other 4 (4,5,6,8)? Injector harness's wired in firing order for each bank effectively doubling injection speed.

Just thinkin out loud.....
 

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wowers, thats some good reading charles, thanks for spelling it out, is there anyway in this crazy world to use the HIPO side a 6oh injector on a 7.3 body? T0T, in my skulking around i have heard someone was trying to get what you describe working, bean maybe? cant remember
 

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I think what has been tried is twin IDM's. I don't think this will fix the buffer in the PCM though, so you would still have regression past 2800 rpm. You would need to duplicate the signal to the second IDM giving you a 16 channel IDM, but I only heard hearsay of this modification and I'm not real sure if it worked or not.

:doh:
 

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Ok forgive me for not knowing my acronyms, but what is "WOS"?
 

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there were some talks about this very subject about a year back on another board, but the conversation was why does a cummins run at higher rpms than a stroke.

If we take the existing info in this thread we see that 1/4 of a revolution of the crank is available for use for injection events and usually is roughly equal to the injector PW at higher loads and rpms. If you do the math you will see that the PS can run up to a PW of roughly 4.55ms at 3300, our redline. The cummins does not see this small of a pulse width until 4400 RPM. Both of these rpm numbers sound rather familiar because I hear a lot of Cummins running around 4500 or so at the pulls. For a PS to run up to 4400 rpms, our available PW is only 3.41ms. I suspect that the fastest a PS injector can fully empty its fuel is roughly 2900 rpm, which equates out to a 5.17 ms PW.

From everything I have read and heard I do not see how we can capitalize on maintaining 5 ms PW's over 3000 rpm unless someone creates a new PCM/IDM combo because of the inherant limitations of the existing electronics we are running.

The actual fuel injection event problably only takes roughly 2-3 ms, but we have so much ramp up time and lag in our electronics that we could start the ball rolling early, so to speak, and the fuel will end up being injected at the correct time. The only way to do this is to overlap the PW signals at the PCM/IDM.
 
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