N54 Injector limits?

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Originally Posted by Tony@VargasTurboTech

As far as fuel, I am not going to get into how the fuel is routed, it took many many revisions to get a fuel supply scheme that would work properly. My guess is now that these tables are open other DI solutions will surface, and I am not trying to give them a head start. For wiring, the wiring is simply ran to both pumps meaning the DME has control of both FCV's. So in theory if pressure is dropping, the DME should just adjust voltage to both pumps and bring it up. In practice its obviously not that simple.

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Ok, I was just curious about the wiring anyway. Didn't even think of fuel routing. I assume since it works w/ your control scheme (not using DME for HPFP #2 ) then it is 100% not a fuel line routing issue.

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Originally Posted by jyamona

Ok, I was just curious about the wiring anyway. Didn't even think of fuel routing. I assume since it works w/ your control scheme (not using DME for HPFP #2 ) then it is 100% not a fuel line routing issue.

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If you force the pump to provide fuel, it does so. If you let the DME decide when it needs fuel, you get very inconsistent results.. Email me, this is all stuff I prefer to discuss off forum

Well considering the continental engineer conversation and the tech docs both saying the n5x is capable of stratified injection I think it's pretty safe to say hardware wise were good. The real question is whether the software (tables and corresponding logic) was ever truly completed and if it exists whole in our rom versions.

We should at least be able to spray into the compression stroke.

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Originally Posted by NniftyFour

Well considering the continental engineer conversation and the tech docs both saying the n5x is capable of stratified injection I think it's pretty safe to say hardware wise were good. The real question is whether the software (tables and corresponding logic) was ever truly completed and if it exists whole in our rom versions.

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There are tables for stratified injection as well. I'm leaning towards it not being used, but I will define them anyway and it can be tested.

As for the diagram showing when 1 pulse vs 2 and 3 is used, with the load to torque tables, I'd wager we can force the DME to use any of those modes by manipulating the output torque :)

It's going to take probably 2x more hours than I thought to define all the DI stuff though...they changing the table dimensions between the DAMOS and IJEOS. It's good because it gives more resolution, but bad because finding them in IJ just became much more difficult.

@lcvette, Moving relevant injector discussion here:


There are two injector duration tables, one for low energy range piezo, and one for high energy range. The duration value is in "ms," I'm trying to determine the axis units. The tables state "for different injector pressure differences", so I'm assuming one axis is cylinder pressure and the other is rail pressure.


Low energy: x-axis goes from 0 - 37689, and the y-axis goes from 471 - 41457
High energy: x-axis goes from 0 - 30200, and the y-axis is the same as above.

Anyone have any ideas that would make sense?

Standard unconstrained piezo actuator input is voltage and output is displacement. If blocked or constrained it's usually calibrated as volts to force. Displacements are tiny so they are often used in multiple layers/stacks to get more stroke so it may be low energy only hits a subset of a stack, high energy the whole stack?

It works in reverse too, applied displacement or force will generate a voltage. Most accelerometers are piezos with a reference mass glued to it or to a lever with a ref mass on it, and the input is acceleration on the ref mass and the output is in volts (calibrated to g's using known ref mass or mass + lever arm).

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Originally Posted by ajsalida

Standard unconstrained piezo actuator input is voltage and output is displacement. If blocked or constrained it's usually calibrated as volts to force. Displacements are tiny so they are often used in multiple layers/stacks to get more stroke so it may be low energy only hits a subset of a stack, high energy the whole stack?

It works in reverse too, applied displacement or force will generate a voltage. Most accelerometers are piezos with a reference mass glued to it or to a lever with a ref mass on it, and the input is acceleration on the ref mass and the output is in volts (calibrated to g's using known ref mass or mass + lever arm).

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Very interesting post. Always wondered exactly how most Accelerometers worked.

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Originally Posted by Tony@VargasTurboTech

Very interesting post. Always wondered exactly how most Accelerometers worked.

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They are pretty cool materials. Used to work with the DARPA smart materials gang doing insane blue sky military stuff with piezos. Like you can make carbon fiber beams and struts with variable directional stiffness properties, and then glue or embed piezo elements onto/into them and have controllable multi-axis bending carbon fiber beams. Think helicopter rotor blades that change shape, damp vibrations, etc. Fun times.

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Originally Posted by ajsalida

Standard unconstrained piezo actuator input is voltage and output is displacement. If blocked or constrained it's usually calibrated as volts to force. Displacements are tiny so they are often used in multiple layers/stacks to get more stroke so it may be low energy only hits a subset of a stack, high energy the whole stack?

It works in reverse too, applied displacement or force will generate a voltage. Most accelerometers are piezos with a reference mass glued to it or to a lever with a ref mass on it, and the input is acceleration on the ref mass and the output is in volts (calibrated to g's using known ref mass or mass + lever arm).

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Yep, you are correct. The injectors have a large stack of piezo actuators. The applied voltage range is constrained, there is a min and a max, units are mJ. I haven't found any "calibration" table for them, however that is why they must be coded when installing new injectors. The values that you input during the coding are their calibration data.

I think I have the axis units figured out too. I will post an update tomorrow detailing that, and give you guys some of the actual table data to look at.

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Originally Posted by jyamona

There are tables for stratified injection as well. I'm leaning towards it not being used, but I will define them anyway and it can be tested.

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if it's there, but not used... woo extreme fuel economy mode! :P

I just saw this ... Very interesting! I ran some simple conversions and didn't find any pressure related units to convert to that matches up with those monster numbers. But I started wondering if perhaps it was converting to force. I didn't get very far before dinner and family time. But it sounds like you got it figured out and the reply above sounded well informed. More then I could have helped by far. Looking forward to your findings!

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Originally Posted by jyamona

Yep, you are correct. The injectors have a large stack of piezo actuators. The applied voltage range is constrained, there is a min and a max, units are mJ. I haven't found any "calibration" table for them, however that is why they must be coded when installing new injectors. The values that you input during the coding are their calibration data.

I think I have the axis units figured out too. I will post an update tomorrow detailing that, and give you guys some of the actual table data to look at.

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I was wondering if coding injectors was related to this, good to know. Nice work!

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Originally Posted by Tony@VargasTurboTech

I think what a lot of people are forgetting here is. With the stock HPFP in place alone, its not the injecting, or injectors causing the issue. The HPFP nose dives meaning it cannot even deliver the fuel asked of it for the small injection window it is already using. Trying to lengthen the injection window is only going to compound the situation, if the pump already cannot deliver enough fuel. For this to work we will 100% need the HPFP solutions we have pioneered to use the DI system only to make big power. The main hurdle is, we still are not 100% happy with the control scheme using the double barrel, we got it work, and work well. But I would prefer if the DME had complete control of both, but when you give it control of both, you lose all consistency. There is still work to be done on that front. Terry was going to integrate dual pump control into the JB, but it looks like he has abandoned that in favor if PI control. Maybe one day we will have both.

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Hows the single barrel working. Does the DME freak out about that?

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Originally Posted by Abacus38

Hows the single barrel working. Does the DME freak out about that?

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Single Barrel, 100% seamless. DME has no idea the pump moved to the belt. It works well