Heui Injection

[lincolnlocker]

Who is this Charles character...... ?

Once all the electrical is sorted out for MEUI, or the 4.5 ratio injectors that HRT and Cass were working are finally installed in a truck…

Who is still making a billet block for 7.3’s?

Holy shitballz! Look who the cats drug in! Welcome back boys! Been a minute.

 

[Charles]

I have talked to Joe at Scheid and Ron at Hypermax and everyone else I could think of.... it should work.

I have a couple Mack E7 Unit pumps on my desk and drew up a quick Cad drawing for length and it should be roughly 15 inches. That would put you just in front of a turbo in the stock location. Intakes would have to turn up.

I think I can use the stock Mack cam and turn the EUI lobes off and tig them onto the right round stock and make a cam that way. Use my indexable rotary table on the lathe to indicate the lobe positions and obviously match them to the engine firing order.

Mech pump injectors can't take the pressure I'm afraid. Might use the hypermax sleeves and see if they can be modified to hold the Mack injectors. Don't know. I'm afraid you would massacre a mech injector. I blew 7.3 fuel plates and passages to piss one time a good bit below this pressure range in very short order, like a week....

Might have to deal with the symmetrical spray pattern. Good news is that they are 8 holers. I found a video of one pop testing and paused it. Bad news is that they are sized to produce peak pressure at 1800rpm. While that means it would be a towing ANIMAL.... at 4000rpm you would over-pressurize and blow shit to bits...

I would like to find a salvage superduty and grab the engine and various stuff off it and see if I could work a running model into my old red truck with some valvetrain basics like springs and pushrods and some studs and see if the unit pumps can follow the cam profile at 3000rpm, 4000rpm and beyond or if they start bouncing or anything.

If they could function at 4000+ a stock forged might go 800, 900+ on fuel.

Built motor with compounds should go 1500+

 

[Charles]

I was doing some blunt pressure vs flow calculations as a reality check for a second, and if you imagined a 7 holer with 0.012" holes....oh, say.... a 200 nozzle.... and you used the specific gravity of diesel fuel, applicable orifice shapes for a nozzle hole, an in-cylinder pressure of say 2400psi.... so on and so forth and you took some random flow rate of say, 300cc (per thousand) with a pw of 3ms, you could see what sort of injection pressure is being achieved there. I realize that a HEUI has an on time delay that cuts into the commanded pw.... but I also realize a HEUI has an OFF TIME delay that isn't intuitively accounted for. If not for the off delay, a huge nozzle could idle just like stock.... but alas.... even with the slightest pw that will actually fire the injector, they tend to want to over fuel and run ragged with big nozzles..... because..... they don't just snap right off... you have a MINIMUM injection time determined by the time for the magnetic gauss to fade away and the poppet to fight the icp and drop back down, shut down the oil and the pintle to reseat.... I think the on and off delays are very similar in length, and the off delay gets worse as rpm and commanded fuel go up because ICP is climbing and opposing the poppet...

Anyway....

If you just assume the on vs off delays cancel one another, and you actually get 3ms....

For the 7 x 12 nozzle, if you ran it for 3ms and actually acheived 15k psi injection pressure, it would move 433cc. A distant dream. Ok... what if it hit 12k psi? 370cc. What if it were 11k? 352cc in 3. Ok, hell, 9k psi? 308cc in 3ms....

NINE...... thousand psi....

That's a 200 EDM moving 300cc in 3ms. Hardly a wild, hyperbolic example...

Contrast that with say, a unit pump, mechanically locked to crank delivering fuel at 25k psi on that same orifice nozzle. In 3ms that would move 569cc. At 25k psi to inject 300cc would take 1.6ms. 400cc takes 2.11ms. But the unit pumps are running that pressure stock, at sub 2000 rpm. At 3k, 4k+ rpm they would be trying to fatally exceed those pressures. The Bosch EUP system is listed as being capable of 30k psi, so if you let it go there, it should live fine. At 30k psi 400cc takes 1.9ms...... or 1900uS as CR folk would say...

Aside from the ability to radically alter the injection window in terms of crankshaft degrees, let's be honest about how wildly different 400cc at sub 9k psi burns compared to 400cc at 25k+ psi!

Cut the injection window in half, and turn the fuel into vapor.... welcome to CR pressures....

 

[Chvyrkr]

Are there any concerns about IDM flatline or voltage soak at higher RPM’s?

 

[Chvyrkr]

Is it possible to “relief valve” the system to prevent injector destruction?

Or would you just be moving the erosion to a new orifice?

 

[Powerstroke Cowboy]

Looks like you've been doing your homework Charels. I'm glad to see your serious about this. It's time the 7.3 got some love again.

That's to bad mechanical injectors can't take the pressure. If they could that would be a simple bolt on solution from hypermax.

Being the injectors off the mack are built for big pistons, you probably couldn't run much timing before missing the bowls in a 7.3. Do the mack injectors need a fuel return line?

I'm really interested to see where you go with this. I don't mind having to run the intake up. I wouldn't mind choping the HEUI system right off the heads if there no longer needed. That would give even more room to build some killer intake manifolds. I would think that alone would also help the head gain some flow.

Carry on!

 

[Powerstroke Cowboy]

Is it possible to “relief valve” the system to prevent injector destruction?

Or would you just be moving the erosion to a new orifice?

Good question. They do it all the time in CR setups. This would require 8 instead of one.

The simplest would be massive nozzles on the injectors. But, after a point it would only be good for high rpm work. Like hooked to a sled or drag strip.

 

[Charles]

Are there any concerns about IDM flatline or voltage soak at higher RPM’s?

No, the MEUI system is tied to crank rotation, just like a P-pump, so pw keeps dropping as rpm increases for the same fuel quantity to be injected, and fuel pressure keeps climbing until it is either injected... or something snaps or otherwise explodes. Again, just like a P-pump.

MEUI is an electronically controlled mech pump that our trucks are already made to run with variable timing.

 

[Charles]

Is it possible to “relief valve” the system to prevent injector destruction?

Or would you just be moving the erosion to a new orifice?

You size your nozzle for your intended rpm and fueling.

 

[Chvyrkr]

No, the MEUI system is tied to crank rotation, just like a P-pump, so pw keeps dropping as rpm increases for the same fuel quantity to be injected, and fuel pressure keeps climbing until it is either injected... or something snaps or otherwise explodes. Again, just like a P-pump.

MEUI is an electronically controlled mech pump that our trucks are already made to run with variable timing.

Don’t know MEUI, but got the impression that we would still be using the PCM tables through the IDM to control PW.

Based on your posts though, with the correct nozzle and those kind of injection rates, PW wouldn’t approach the limits of the system?

It’s been too long, but we have what, 3.5ms at 4000 RPM? A little less in practice…

 

[Powerstroke Cowboy]

 

[Charles]

The only reason we were fighting the IDM before was because the plunger travel was not tied to the crankshaft rotation. With HEUI the injection rate is pitiful, and independent of rpm. What worked fine at 2000 rpm had nothing driving any urgency by 3000 rpm and it just flatlined.

If you built the injectors described in the first post of this thread, you could increase the injection rate, but as rpm climbs nothing is MANDATING that the injection rate climbs with it. The oil either fills the intensifier piston chamber quicker..... or not, depending on ICP commanded and the flow across the poppet, vs oil per unit time required in that chamber.

There are some ways that can increase oil flow that require an increase in injector on delay, the simplest being increased poppet travel. But that requires increased "over" gap to allow that travel, which increases the on delay of the injector, making the commanded pw higher than the delivered pw comparatively. The injection RATE however, will slightly increase, so the added on delay is simply accounted for with a timing bump. The problem there is when you max out the IDM signal protocol with all that extra baggage in the pw command. Two IDM's fixes that but if the extra curricular pw command isn't needed, you never run into an issue with the IDM because the true injection window, sans any fluff, is well within the IDM signal protocol.

So what's a good way to create a sense of urgency to ensure plunger travel WILL happen in the same crank window, no matter what? A big steel cam lobe underneath it with zero ***s to give. The magic of the P7100 at rpm.

Imagine a P7100 with CR pressures and infinitely variable timing....

Toss in automatic temp based adjustments for starting and altitude just for fun.

Then wrap it up in the fact that a HEUI truck is already made to run it.

Swapping rotella for a cam lobe is a big F'ing game changer.

 

[Powerstroke Cowboy]

I understand what your saying, and agree with it. As rpms go up pw goes down mechanically due to the MEUI being run off a cam. But, fuel flow is not lost. Since the amount of fuel supplied is mechanical off the cam.

Having injectors that keep pressure in check at 5k rpm would probably not make for a good dd/towing injector.

 

[Charles]

I understand what your saying, and agree with it. As rpms go up pw goes down mechanically due to the MEUI being run off a cam. But, fuel flow is not lost. Since the amount of fuel supplied is mechanical off the cam.

Having injectors that keep pressure in check at 5k rpm would probably not make for a good dd/towing injector.

I just suggested that a HEUI with a 200 nozzle could easily be running injection pressures in the sub 9k psi range...

A 200 nozzle can tow the drivetrain out from under your truck.

If a MEUI setup did 30k at 5k, it is entirely likely that it might still far exceed what we have even down at 1500rpm because our current injection pressure is so pathetic, and MEUI pressure could drop by nearly 50% and still possibly DOUBLE what we are doing now....

An NFL defensive end with one arm tied behind his back can still handily beat the shit out of a 120lb pop warner MVP....

Different leagues. Losing a lot of pressure going back down the rpm scale is relative.

 

[Powerstroke Cowboy]

I just suggested that a HEUI with a 200 nozzle could easily be running injection pressures in the sub 9k psi range...

A 200 nozzle can tow the drivetrain out from under your truck.

If a MEUI setup did 30k at 5k, it is entirely likely that it might still far exceed what we have even down at 1500rpm because our current injection pressure is so pathetic, and MEUI pressure could drop by nearly 50% and still possibly DOUBLE what we are doing now....

An NFL defensive end with one arm tied behind his back can still handily beat the shit out of a 120lb pop warner MVP....

Different leagues. Losing a lot of pressure going back down the rpm scale is relative.

If 200% only see 9k psi at the nozzle full song, I would be surprised. They run really clean and cool if they are at only 9k.

I agree 100%. A 200% nozzle injector makes enough clean, cool power to rip your drivetrain apart towing. Even after all these years folks still say they can't make as much egt safe power than a stock or 80% nozzle. Yea right, tell me another one.

Could you imagine 30k psi behind a 200% nozzle? North of 1k would be simple. I do hope your right about what the pressures would be. Even if it's half of 30k at 2k rpm, we would have more than enough fuel to do what we want towing

I do have a question, do the unit pumps have a pressure relief built into them? The reason I ask is the pump sees full stroke everything, the extra fuel has to go someplace. Atan idle we might only call for .7ms of pw, and in a tow tune 1.5 to 2 ms of pw. That would get no where close to using up the fuel volume of the pump. The rest has to go someplace.

With that thought in mind. We might be able to have more pressure than we think at lower rpms.

 

[Charles]

If 200% only see 9k psi at the nozzle full song, I would be surprised. They run really clean and cool if they are at only 9k.

I agree 100%. A 200% nozzle injector makes enough clean, cool power to rip your drivetrain apart towing. Even after all these years folks still say they can't make as much egt safe power than a stock or 80% nozzle. Yea right, tell me another one.

Could you imagine 30k psi behind a 200% nozzle? North of 1k would be simple. I do hope your right about what the pressures would be. Even if it's half of 30k at 2k rpm, we would have more than enough fuel to do what we want towing

I do have a question, do the unit pumps have a pressure relief built into them? The reason I ask is the pump sees full stroke everything, the extra fuel has to go someplace. Atan idle we might only call for .7ms of pw, and in a tow tune 1.5 to 2 ms of pw. That would get no where close to using up the fuel volume of the pump. The rest has to go someplace.

With that thought in mind. We might be able to have more pressure than we think at lower rpms.

Try some orifice size vs pressure calculations for how much pressure will move 300cc of diesel in 3ms across a 7 x 12 nozzle.

The MEUI or any mech pump for that matter work on the principle of a spill port. If the rack is at shutoff, a P7100 just spills 100% of the fuel right back to the fuel rail on each stroke. A de-energized MEUI does the same. The fuel just keeps going into and out of the P&B.

When you move the rack and twist the P-pump helix off the shutoff, or when you energize a MEUI, the path to spill fuel back to the rail is cut off and injection commences. In the case of a P-pump, the duration is determined by the point at which the helix again uncovers the spill port and injection ceases as the remaining stroke blows back into the fuel rail. For the MEUI the same thing happens when the solenoid is de-energized.

Sizing nozzles to match the cam ramp rate and desired rpm and fuel quantity is mech pump 101. Nothing new. The part that's different, is that we can vary the timing dynamically and instantly vs rpm, boost, EOT...... and the same for pw.... all from our OEM PCM and sensor package. The signal from the IDM might also be gtg right out of the box. Solenoids look way similar and these systems were born at the same time period.

And we're gonna call for a lot less than 7ms at idle..... lol

 

[Powerstroke Cowboy]

Try some orifice size vs pressure calculations for how much pressure will move 300cc of diesel in 3ms across a 7 x 12 nozzle.

The MEUI or any mech pump for that matter work on the principle of a spill port. If the rack is at shutoff, a P7100 just spills 100% of the fuel right back to the fuel rail on each stroke. A de-energized MEUI does the same. The fuel just keeps going into and out of the P&B.

When you move the rack and twist the P-pump helix off the shutoff, or when you energize a MEUI, the path to spill fuel back to the rail is cut off and injection commences. In the case of a P-pump, the duration is determined by the point at which the helix again uncovers the spill port and injection ceases as the remaining stroke blows back into the fuel rail. For the MEUI the same thing happens when the solenoid is de-energized.

Sizing nozzles to match the cam ramp rate and desired rpm and fuel quantity is mech pump 101. Nothing new. The part that's different, is that we can vary the timing dynamically and instantly vs rpm, boost, EOT...... and the same for pw.... all from our OEM PCM and sensor package. The signal from the IDM might also be gtg right out of the box. Solenoids look way similar and these systems were born at the same time period.

And we're gonna call for a lot less than 7ms at idle..... lol

Thanks for the explanation and information.

I've never studied unit pumps or P-Pumps. I figured there had to be a relief valve that dumped the unused fuel. Ot was the only logical awnser.

I get that a unit pump will be just like a P-Pump on fuel delivery, but be fully controlled via tuning vs what it is is what it is. With that being the case the MEUI is far superior to the P-Pump.

I'm looking forward to seeing where you take this. If setup right this could literally be a game changer.


By the way, I didn't say 7ms of pw at idle, I said .7ms of pw at an idle. I'm sure .7 still might be off a little.

 

[BrewTown]

Oh man! After reading many a Charles post over the years, I had a giddy moment to see a new one! This one doesn't disappoint either...

I'm following, and I'm imagining the potential. I have a few thoughts/questions

I'm imagining you are talking a 'housing' with 4 cam lobes driving 8 unit pumps in the valley. Each having a high pressure line to essentially a mechanical injector in the head. Sounds straight forward in concept. I don't think having injector lines that long would pose a problem would it? I know p-pump guys run into surging issues with larger diameter lines right?

The torque figure of 1650 the E7 makes has a caveat, being the 7.3 is ~61% of the 726 cubic inch E7, that power band moves up in the RPM range on the smaller engine to ingest the same amount of air. Everything else constant.

Someone more knowledgeable than me, at what point is the anemic head flow neuter the power? Boost fixes some, but actual CFM and fueling rates equaled, they should make the same power. How are the p-pump trucks doing at rpm?

In a non turbo calculation, the 7.3 at 2500 rpm uses the same CFM as the E7 at 1500. Just as a reference. Am I right in thinking the 7.3 would make the 1650ft/lbs. at 2500 rpm with equivalent fueling and boost then?

In my head, I'm thinking the cam profile to get 50° of advance available, while still having sufficient fuel volume available at low timing may have a long ramp and reduced volume during short duration low timing scenarios. Is a wide rpm range possible with this type of injector? Meaning 500-5000+ rpm? Stroke and volume outputs would be necessary right? I think shifting the entire RPM band up helps this.
1500ft/lbs. at 5252 rpm is 1500hp after all...

Would some sort of pressure relief circuit be a fail safe? Set at like 32k or higher? Maybe a solution if you start blowing things up...

 

[BrewTown]

When creating the pump housing, would it utilize tappets, pushrods and rockers? Roller followers like MOD motors? My thought being rocker ratio could be adjusted to create the necessary plunger travel for the application, and may help utilize existing cam lobe geometry. That's beyond me though...

 

[Powerstroke Cowboy]

When creating the pump housing, would it utilize tappets, pushrods and rockers? Roller followers like MOD motors? My thought being rocker ratio could be adjusted to create the necessary plunger travel for the application, and may help utilize existing cam lobe geometry. That's beyond me though...

All you need is a housing with a cam and a way built into the housing to feed fuel in and out of the unit pump.

Here is a unit pump with the roller lifter.

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