DieselTuner2
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Posting Dyno Graphs
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I think in the D40s you'd be hard-pressed to stamp it with a single boost value, because it's a variable-vane turbo. While on a dyno, you'd think it would just open all the way up, but the ECU may vary the rate depending on the information it receives from the HO2 sensors in the exhaust.
Adding a ChipIt chip will alter that dynamic again, because they also control the boost.
Diesels don't control air, there's no butterfly, so a more important value to look at would be fuel rail pressure.
With different variables like that, it would actually make sense to have three lines on the one graph: fuel pressure, boost pressure and the output at the wheels.
If you could determine the injector duration, you may be able to calculate the actual volume of fuel used in each stroke, and thus get some idea of actual (real) fuel consumption and graph that as well, but I'm not sure how you would get info like that from the ECU because I imagine that it's not something you'd normally obtain through the OBD port, especially in real time.
You could, I suppose, take the real-time ECU's idea of consumption rate and graph that.
How do we judge that any of these mods are safe, anyway? I think most of us would look at how the companies represent themselves, the info given, the responses to questions and how much BS appears to be flowing in our direction. Some of us also wait to see what has happened to others' vehicles in this regard.
Just going on THAT info, ChipIt seems to be a long way in front - Robert gets on here with some fair info and doesn't seem to include a lot of the guff that you'd expect from someone trying to hard-sell their product.
What we really need in a chip, while I've got you here, is something that intercepts the injector signals. Talk to Bosshog about this too, he and I have had more than a few conversations regarding this topic and we've figured that we can save even more fuel by removing injector commands during the exhaust stroke - but the only way to do that is to have a crank angle sensor connected to the chip, and intercept the injector signals so that you can have a command like:
IF [cylinder(x) is on power stroke] THEN allow injector open ELSE ignore signal
That would require a very fast setup with short wiring to reduce signal lag. It's not a cheat like a rail pressure modifier.
Can that be done? Not sure. Perhaps it would be easier to modify the ECU's programming, which is something else I'm going to look into (with the objective being to empower the vehicle owner into being able to do that themselves, rather than keep coughing up more $$ every time Nissan replace the program).
Adding a ChipIt chip will alter that dynamic again, because they also control the boost.
Diesels don't control air, there's no butterfly, so a more important value to look at would be fuel rail pressure.
With different variables like that, it would actually make sense to have three lines on the one graph: fuel pressure, boost pressure and the output at the wheels.
If you could determine the injector duration, you may be able to calculate the actual volume of fuel used in each stroke, and thus get some idea of actual (real) fuel consumption and graph that as well, but I'm not sure how you would get info like that from the ECU because I imagine that it's not something you'd normally obtain through the OBD port, especially in real time.
You could, I suppose, take the real-time ECU's idea of consumption rate and graph that.
How do we judge that any of these mods are safe, anyway? I think most of us would look at how the companies represent themselves, the info given, the responses to questions and how much BS appears to be flowing in our direction. Some of us also wait to see what has happened to others' vehicles in this regard.
Just going on THAT info, ChipIt seems to be a long way in front - Robert gets on here with some fair info and doesn't seem to include a lot of the guff that you'd expect from someone trying to hard-sell their product.
What we really need in a chip, while I've got you here, is something that intercepts the injector signals. Talk to Bosshog about this too, he and I have had more than a few conversations regarding this topic and we've figured that we can save even more fuel by removing injector commands during the exhaust stroke - but the only way to do that is to have a crank angle sensor connected to the chip, and intercept the injector signals so that you can have a command like:
IF [cylinder(x) is on power stroke] THEN allow injector open ELSE ignore signal
That would require a very fast setup with short wiring to reduce signal lag. It's not a cheat like a rail pressure modifier.
Can that be done? Not sure. Perhaps it would be easier to modify the ECU's programming, which is something else I'm going to look into (with the objective being to empower the vehicle owner into being able to do that themselves, rather than keep coughing up more $$ every time Nissan replace the program).
DieselTuner2
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I'm not going to disagree with the substance there. More information is good. It's unlikely you'd get many companies detailing any detrimental effects their products made, they wouldn't make as many sales.
As for the Unichip, you say it monitors the crank angle sensor already. Does it allow for the exclusion of injector commands when the cylinder is on the exhaust stroke, or does it not actually control the injectors?
DieselTuner2
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I'm more thinking about removing regeneration injection strokes, which MUST be prolonged, as without a DPF our cars can blow clouds of white smoke every 100-300km. That's not a tiny amount of fuel, and this is specifically the part that I am seeking to eradicate.
Remapping the ECU it is, then. I'll have to start looking for software to do that, and a means of installing it. I know precisely what I want to do with it - ignore the differences between the two pressure sensors attached to DPF.
If possible I will try to work out how it decides when to make a large squirt for CAT reductant supply as well, so that can also be removed from the code.
This would:
* leave the ECU operating power injection (pre, main and post) as normal
* leave any chip operation intact
* remove fuel waste
Time to start searching. If it's in assembler, it'll take me a bit because my assembler is a little rusty - I don't expect it to be in Java, Perl, C/C++ or other language I'm familiar with though!
Thanks for your effort in this.
Remapping the ECU it is, then. I'll have to start looking for software to do that, and a means of installing it. I know precisely what I want to do with it - ignore the differences between the two pressure sensors attached to DPF.
If possible I will try to work out how it decides when to make a large squirt for CAT reductant supply as well, so that can also be removed from the code.
This would:
* leave the ECU operating power injection (pre, main and post) as normal
* leave any chip operation intact
* remove fuel waste
Time to start searching. If it's in assembler, it'll take me a bit because my assembler is a little rusty - I don't expect it to be in Java, Perl, C/C++ or other language I'm familiar with though!
Thanks for your effort in this.
DieselTuner2
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Oh I'm absolutely sure about the white smoke in this case, it was reported by someone (reliable) that removed their cat ... so it has to be unburnt fuel.
Bosshog, are you reading this?
This chip - with a DPF delete pipe + no CAT would seem to tick most of the boxes you and I have been discussing over several other threads as well as privately.
Northside, part of the problem with fiddling with the sensors the way we've been doing things is that Nissan deliberately causes fluctuations in the injector durations that appear as fluctuations in the O2 readings at the Heated Oxygen Sensor (Bank 2). If we do something to make the O2 sensor not respond accordingly, it lights the bloody CEL on us.
The pressure sensors are pains in the ass as well, being somewhat fiddly with the distance-from-tube if you're to NOT get the CEL or worse, the dreaded limp mode.
If the Unichip can solve all this, it's very close to ideal, as far as I can tell.
DieselTuner2
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Leprechaun
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I can't find it. I can find the petrol one, but not the diesel stuff. We know it works: pull the HO2S out (unplug it) and the CEL comes on after a short time. Plug it back in and the CEL goes out after the next restart.
It's looking for a reaction in the oxygen levels based on a minor fluctuation in the amount of fuel delivered. If it's injecting (say) 0.0417ml of diesel per power stroke on all 4 cylinders, it should expect (knowing the value given by the MAF and BOOST sensors) a certain level of oxygen in the exhaust. It then increases the injection rate to say 0.0420ml for a very short period and SHOULD see a corresponding fall in the available oxygen detected by the HO2S.
This sucker's in the DPF, along with a pressure sensor before the filter material and a pressure sensor after. If I find the actual reference in the workshop manual I'll let you know.
Sorry for going off topic, maybe we should take this over to the DPF thread where some of us were discussing this a few months ago.
It's looking for a reaction in the oxygen levels based on a minor fluctuation in the amount of fuel delivered. If it's injecting (say) 0.0417ml of diesel per power stroke on all 4 cylinders, it should expect (knowing the value given by the MAF and BOOST sensors) a certain level of oxygen in the exhaust. It then increases the injection rate to say 0.0420ml for a very short period and SHOULD see a corresponding fall in the available oxygen detected by the HO2S.
This sucker's in the DPF, along with a pressure sensor before the filter material and a pressure sensor after. If I find the actual reference in the workshop manual I'll let you know.
Sorry for going off topic, maybe we should take this over to the DPF thread where some of us were discussing this a few months ago.
DieselTuner2
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I am here Tony. I can confirm that the white smoke is caused from diesel being injected on the exhaust stroke for the purpose of adding an accelerant into the DPF to create the regen. When the Cat and DPF are removed the diesel remains unburnt creating plumes of white smoke, which always happens when you are in peak hour traffic!!
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DieselTuner2
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D
Dave
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Well done.
Glad to see that the 3 inch wasn't needed.
Glad to see that the 3 inch wasn't needed.
