Can anyone decode this Greek? (Injector Data)

[samh_08]

I am working on the black magic injector tables in my tune. I started out with stock 26.6lb/hr truck injectors (05 Chevy 6.0L.) After Heads/Cam/Headers I figured it would be wise to get some bigger injectors.

I bought the new shorty LS2 injectors which are flowmatched at 42lb/hr @ 4 bar (58psi). At first I copied as many tables I could from a LS2 tune to my tune. I dont like to assume that both PCMs run the same way especially when there is two different LS2 tunes (at least injector data.)

Long story short, I called John from FIC (Fuel Injector Connection) and got all the raw data I could from the injectors I bought from him. He faxed over what he had, and I found out that most of it was written in Greek.

Attached to this post is what he sent me via fax. I want to get the proper data from that data and somehow put it in my tune. I am running a GenIII PCM. If I looked at it long enough Im sure I could figure it out, but I'll ask here first :grin:.

Let me know your thoughts,
Sam

[Aloicious]

I am working on the black magic injector tables in my tune. I started out with stock 26.6lb/hr truck injectors (05 Chevy 6.0L.) After Heads/Cam/Headers I figured it would be wise to get some bigger injectors.

I bought the new shorty LS2 injectors which are flowmatched at 42lb/hr @ 4 bar (58psi). At first I copied as many tables I could from a LS2 tune to my tune. I dont like to assume that both PCMs run the same way especially when there is two different LS2 tunes (at least injector data.)

Long story short, I called John from FIC (Fuel Injector Connection) and got all the raw data I could from the injectors I bought from him. He faxed over what he had, and I found out that most of it was written in Greek.

Attached to this post is what he sent me via fax. I want to get the proper data from that data and somehow put it in my tune. I am running a GenIII PCM. If I looked at it long enough Im sure I could figure it out, but I'll ask here first :grin:.

Let me know your thoughts,
Sam

That, my friend, is a stock Ford injector datasheet. in fact, it looks like this exact one: http://www.fordracingparts.com/parts/ics/m-9593-mu32.pdf
taken from here:
http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=10512

the problem with that, is the way Ford calculates the offsets and small pulse tables is quite a bit different than what GM does. IIRC, Ford combines the small pusle table and the injector offsets into a sort of 'total offset' type of table, so using the exact data from that chart in GM tunes will NOT give the accurate and correct results. and unfortunately you're no closer to the correct info than you were before. not even the IFR data is directly applicable because Ford tests their injectors at 39.15psi of fuel pressure, so conversions there are necissary as well to be more correct for your specific setup. in fact even the MINPW data (minimum pulse width) on that sheet is in relation to a fuel system PSI of 39.15, so I don't know what effect a standard 4 bar (58 psi) GM fuel system would have on alot of these variables.

unfortunately, the correct data is pretty hard to come by in most cases. there is only 1 company that I have seen which can actually test for these variables, but the testing is pretty expensive. it's Paul with YAW power. he has some good reading on his site about injector dynamics if you look it up.

Other than that, you could either get some stock GM injectors and copy the injector data from a tune which uses those injectors in a stock application.

I've heard good things about Jon and FIC's work, and I am not trying to contradict that. however I have a problem with this stock Ford info being given out for GM applications without explaination or how to extrapolate useful data, you're not the first person I've seen that FIC has sent the ford tables to for a non-compatable GM application.

[5.7ute]

I agree. I spent a few minutes converting the data over to our units & I dont believe there is enough info to extrapolate to our tables. None of the offsets are linear, as has been shown in the past. So the only data we can use is at the 60lb delta pressure on those sheets. I will keep playing with this data though & see if I can come up with anything.

[samh_08]

Just what I wanted to hear...:doh2:

How can they be Ford if they are used on LS2's? I thought I finally was going to get a break. If anyone at all can help me, please do! Take it as a challenge :good:.

Thank you for the info so far, hopefully we can get something figured out.

Sam

[Aloicious]

Just what I wanted to hear...:doh2:

How can they be Ford if they are used on LS2's? I thought I finally was going to get a break. If anyone at all can help me, please do! Take it as a challenge :good:.

Thank you for the info so far, hopefully we can get something figured out.

Sam

well....he's either sending you the ford injectors and giving you the ford data for them, OR he's sending you the LS2 injectors, and just giving you the ford data from 'simmilar' injectors, (though the data isn't simmilar, and likely the injectors are somewhat different as well).

if you can verify that they actually ARE genuine LS2 injectors, I would take the data from an LS2 tune if you can.

to Jon's defense, he most likely isn't able to test the dymanic data like offsets, so he's just trying to provide simmilar info that he can find. and maybe he's not aware of the GM/Ford tuning differences. BUT, its just very misleading to the customer to give them incompatable ford data for an obvious GM application, and not inform them of that.

I'm working on designing a dynamic flow bech to test these odd injector dynamics, partially for fun (I find injectors fascinating), and partially for some of my engineering classes. once I get it finished I'd love to test some various injectors to help y'all out, but that is quite a ways away as I'm still designing the circuitry for it.

[samh_08]

Here is the response I received back from him. Most of our conversation was on the phone, but I PM'ed him tonight to get more answers.

Proceed :)..

hi the injector is the same as ford uses. Also Bmw, rover etc. ford is the only OE that published injector data. All ev14's like ls2 are made by bosch, Yours are factory ls2, using the same coil and injector body in the fords. there is no such thing as a ford injector. Since you cant load a ls2 tune in your computer, this data is the closest you will get. Unless you can get a tune from a guy on efi live that has put one in. voltage offset, latency, deadtime is all the same thing. Did you fire up the engine yet? You might want to get to a dyno and do a live tune over a mathematical. Alot of guys start with the stock tune and change just the IFR vs voltage table, then fine tune the ve.. what did you do so far and whose tuning it?
jon

[joecar]

You should be ok with the LS2 tables...

Post the two LS2 files you're looking at.

[samh_08]

You got it Joe! I could also look up what exact year and model GM used this injector..Anyone have that kind of resource available to them? Seems like a better way of tracking down my true numbers.

Tune file 1 = 05 Corvette LS2 6.0L
Tune file 2 = 06 GTO LS2 6.0L
Tune file 3 = My current hacked tune

Notice that the LS2 has different injector tables than me. This makes me wonder if Im only getting half the picture...

[Aloicious]

Here is the response I received back from him. Most of our conversation was on the phone, but I PM'ed him tonight to get more answers.

Proceed :)..

he's correct, its not a 'ford' injector, its made by bosch, but it is made to ford's specs, and there are differences between different EV14's even within different manufactuing runs you will get variances in injector charactoristics, but these are typically small enough not to worry about, but go look at a bunch of different tunes using the same injectors, you'll see different small pulse adders, different voltage offsets, etc.

thats not the complaint I have with what he's told you though. the issue I have with his info is that the ford PCM tables ARE NOT THE SAME as GM's so just putting the ford data (from his fax) in WILL NOT be correct, he says that the faxed data is the most correct for the injectors, he is probably correct, in a ford tune, not a GM one. they calculate and use these tables differently. Greg Banish (eficalibrator here on the forums) is a good guy to talk to about the differences between the the ford and GM tables, he used to be a ford OEM calibrator. its nice that Jon is going to the trouble to at least provide some info, I just wish he'd tell people, that the info he's giving is from the ford OEM tables and may not work in other applications. you're the second person I've talked to who's tried using this info in a GM tune and didn't know that the ford and GM tables aren't directly compatable with each other.

just do like Joe mentioned and pull the data from a simmilar LS2 tune. you should be good. I'm at work so I can't check out your tunes here.

[scdyne]

I had the same general questions last month and here is what Greg Replied to me in a PM.


Be careful directly comparing the Ford calibration summary to units that would be plugged into a GM ECU. Not only are the working pressures different, but the point in time represented by the Ford offset and GM offset are different. In order to solve for the GM offset and short pulse adjust I had to first interpolate to 58psi using Ford units then back-solve to GM units from the raw mass vs time curves at the reference voltage.

...all that said, the minimum pulsewidth is really just the shortest controllable opening and closing event at whatever pressure you're using. This is either found by testing a few thousand injectors and statistically analyzing the behavior or by just taking a SWAG based on empirical behavior on a real engine or three. The numbers in the DVD's disc are based on the latter experience and should allow for a clean idle at stoichiometry on most engines.

I did math out everything including the minimum pulse width (my specific question to greg) in the last few weeks and once I get the GM EFI Tuning DVD, I'll know weather I was correct or not. I can hope, but I know working in Instrumentation Testing for a living that chances are I'll be wrong.

[Aloicious]

I had the same general questions last month and here is what Greg Replied to me in a PM.

I did math out everything including the minimum pulse width (my specific question to greg) in the last few weeks and once I get the GM EFI Tuning DVD, I'll know weather I was correct or not. I can hope, but I know working in Instrumentation Testing for a living that chances are I'll be wrong.

yeah, thats exactally what I mean about the data not being interchangable.
let us know what you find out. what injectors were you doing the math for, and what did you get, out of curiosity?

[redhardsupra]

I've tried to create a complete Ford <-> GM converter of fuel system model parameters on probably more than a dozen occasions, and I still cannot claim full victory. The voltage offset table is simple to do, that's just a surface fit. The IFR is simple as well, it's just pure Bernoulli.

Short Pulse Adder is where it gets complicated. The interesting part, after trying to get it from many different angles, I've concluded that you cannot really establish SPA from pure flow-sheet numbers. You actually need to know what MAP (and the resulting Fuel Pressure across the injector) you're going to have at given IPW. This means that Greg's conversions are either bogus, or he's assuming some sort of 'oughtta be good enough for everybody' FuelPressure, which is also no good, as I've done some simulations, and even small FuelPressure swings result in rather significant changes to the SPA results.

Greg keeps talking about how the Ford<->GM conversion is simple and we should be able to just do it ourselves. If it's so simple, why hasn't he posted the damn formulas online, or publish it in his books/dvd? I'd love to whip out and compare...some formulas ;)

[LinearX]

Greg keeps talking about how the Ford<->GM conversion is simple and we should be able to just do it ourselves. If it's so simple, why hasn't he posted the damn formulas online, or publish it in his books/dvd? I'd love to whip out and compare...some formulas ;)

I thought that was supposed to be part of his DVD. Telling us how to convert Ford data to GM.

[Aloicious]

I thought that was supposed to be part of his DVD. Telling us how to convert Ford data to GM.

well, not really, he talks about what is different between the two mfg's use of injector data, where to find the injector data tables in HPT, and efilive, and then talks about how to decipher his injector spreadsheet. then he includes a spreadsheet with some data for a few injectors. he doesn't explain any formulas, or differences between fueling system setups (i.e. referenced vs. non referenced), or where he got the injector data (i.e. the injector data sheets from ford, or elsewhere...he was/is a OEM calibrator for ford, so there is a chance he has access to different/more complete data about the ford injectors than just what is on those publicly published sheets, but who knows).

RHS, I know for a fact he does some 'good enough' calculations on the SPA table, after all he only does linear interpolation between the data extremes on there, and I have yet to see a linear OEM GM table, ever. he does talk about how that is what ford does, and I understand (graphically) where that comes from, but I'd like to know what his formulas are for extrapolating the SPA table numbers from in the first place, because as I understand it, ford does not use an actual SPA table at all. but rather incorporates the SPA into other tables (I could be wrong about this, but that is my understanding)

as far a FP goes, he makes no reference to different fueling designs and how it DOES affect the tuning tables. his voltage offset table varies with MANVAC, so one would assume that his SPA table would also be based off a non-referenced fueling setup, however, perhaps he's doing the SPA table from a referenced FPR setup point of view? who knows.

[5.7ute]

RHS, I know for a fact he does some 'good enough' calculations on the SPA table, after all he only does linear interpolation between the data extremes on there, and I have yet to see a linear OEM GM table, ever. he does talk about how that is what ford does, and I understand (graphically) where that comes from, but I'd like to know what his formulas are for extrapolating the SPA table numbers from in the first place, because as I understand it, ford does not use an actual SPA table at all. but rather incorporates the SPA into other tables (I could be wrong about this, but that is my understanding)



The Ford system appears to use two IFR's. One for where the IFR is linear above the breakpoint. A different IFR for when the pulsewidth is below the breakpoint & fuelling is erratic. However with having zero to do with ford calibrations this is an educated (or maybe uneducated) guess.
SPA looks like a real PITA to tune without actual flow data. Even then some low PW areas will cause grief. For example if there is an area where fuelling starts to drop from linear at say 1.4ms, is at its lowest at 1.3ms gets back to linear around 1.1ms. If the calculated pw is 1.2ms, adding 0.1 ms will actually lower the amount of fuel injected.

[redhardsupra]

Would it not it be just easier if people just posted their formulas publicly? :)

[Aloicious]

Would it not it be just easier if people just posted their formulas publicly? :)

:cheers:

[joecar]

+1.

[eficalibrator]

Short Pulse Adder is where it gets complicated. The interesting part, after trying to get it from many different angles, I've concluded that you cannot really establish SPA from pure flow-sheet numbers. You actually need to know what MAP (and the resulting Fuel Pressure across the injector) you're going to have at given IPW. This means that Greg's conversions are either bogus, or he's assuming some sort of 'oughtta be good enough for everybody' FuelPressure, which is also no good, as I've done some simulations, and even small FuelPressure swings result in rather significant changes to the SPA results.
I'm doing it the same way the guys from Siemens/Conti, Delphi, and Bosch do it when they supply a product to the OEMs for serial production. Sure the small pulse phenomena change with pressure, but the industry standard has been to characterize primarily at the nominal rail pressure. That's 2.7bar for a Ford, 4bar for a GM. Luckily, the Ford data includes the coefficient for pressure changes to both low slope and breakpoint, which may not directly follow the Bernoulli equation since they're not linear flow through a fixed orifice. One just needs to apply these changes BEFORE plotting the mass vs time curve at a new pressure.


Greg keeps talking about how the Ford<->GM conversion is simple and we should be able to just do it ourselves. If it's so simple, why hasn't he posted the damn formulas online, or publish it in his books/dvd? I'd love to whip out and compare...some formulas ;)
I'm not advertising the conversion as "simple." It took me several attempts over a long period of time to get it to line up right too. I have a bunch of work into the tables I included in the DVD. Fundamentally, most of the work converting from Ford-->GM data centers around variants of "Y=mX+b" The trick is that Ford uses several "m's" and several "b's" that also vary with pressure. I had to apply linear fits across short regions of mass flow to create the final curve, which is really a stepped line.

Is it perfect? Nope. Is it close enough to pass Tier2Bin5 emissions for the guys in Dearborn? Yep. Most people in the aftermarket have too much trouble with proper airflow estimation and torque control to be able to get that critical of injector data.

People keep asking for the raw data, but I'm in the business of teaching them the proper application of it as well. Even with the right raw data, many people jump to conclusions and end up applying it incorrectly.


RHS, I know for a fact he does some 'good enough' calculations on the SPA table, after all he only does linear interpolation between the data extremes on there, and I have yet to see a linear OEM GM table, ever. he does talk about how that is what ford does, and I understand (graphically) where that comes from, but I'd like to know what his formulas are for extrapolating the SPA table numbers from in the first place, because as I understand it, ford does not use an actual SPA table at all. but rather incorporates the SPA into other tables (I could be wrong about this, but that is my understanding)
If you look at how Ford defines it, there's just two different slopes. GM has one slope (table vs pressure) and a time offset. The Ford "low slope" IS the the same effective function as the GM SPA table. They just define the mass versus time relationship from different angles. GM assumes nominal rail pressure for the SPA table since there's no axis for pressure in the table. Could there be more precision with a pressure axis? Sure. Is it needed? Would the benefit outweigh the necessary software code and engineering effort to support it? Probably not, so they focus calibrators' time elsewhere. It's a matter of "knowing when to say when."


The Ford system appears to use two IFR's. One for where the IFR is linear above the breakpoint. A different IFR for when the pulsewidth is below the breakpoint & fuelling is erratic.
Bingo.

[redhardsupra]

...and still no formulas.

YAWN.

[eficalibrator]

...and still no formulas.

YAWN.
Were you hoping to goad me into spoon feeding you with some single, simple plug and chug formula?

[Aloicious]

Were you hoping to goad me into spoon feeding you with some single, simple plug and chug formula?

Greg, I have alot of respect for you and the experience you have, so don't take this response as a negative one. but with all due respect, no one in this thread or other wise asked for a 'simple plug and chug' formula, and no one is expecting it to be as such.

you have to realize a good amount of us here aren't your typical back woods DIY shade tree tuners, which I'm sure you get to deal with at times through your instruction, and I'm sure you do have to tone down the complexities of your tuning techniques to cater to everyone. However, many of us have tuning and mechanics as a hobby, and that our background is in much more extensive areas like engineering, with strong backgrounds in fields like physics, and advanced mathematics. so, once again, we didn't ask for, and we don't expect a 'single, simple plug and chug formula'.

What I (and others) do expect is some kind of explaination of how you are comming up with your numbers. I don't care if your formula is as complex and intricate as it can be. what I have a problem with is just throwing raw data out there and basically saying 'its correct, trust me', with no way for someone who is able to, double check it, even if it is for their own peace of mind and nothing else.

For example, If you took a course at a university, you wouldn't expect the professor to only give answers to the corsework and exams, you'd expect him to teach the formulas, explain the principles, and give you the background needed to actually learn something.

I fully understand that you make your living off of teaching people this kind of stuff and you may be hesitant to share information like this publically, especially when its a part of how you obtain your livelyhood. but when people who are advanced enough to understand the theory behind the data that you provide come asking for the theory and you respond with "Were you hoping to goad me into spoon feeding you with some single, simple plug and chug formula? ", I find it disrespectful, juvenile, and petty. if you'd prefer not to share information like this because it is part of your livelyhood, why not just come out and say that. I'd have far more understanding in your hesitation to share info for that reason rather than trying to belittle other people and their ability to comprehend a subject.

and if, by chance, you are concerned with losing income due to posting information like this on a forum, why not write another book or something that is geared more towards the truly advanced tuner who is able to understand things like your injector data formulas, etc, its obvious through several of these type of threads that there is somewhat of a market for that, although it may not rival the sales of Harry Potter or something (but what public technical publishing has?), it would still provide the desired information, while still pulling in a profit on it. I own both your book and DVD, have watched and read them many times, and though they are well done, and I'd recommend them to any beginner in tuning, anyone who is able to find the tables they need, do an AutoVE, AutoMAF, and use a dyno, they will likely be too basic. There IS a market for much more advanced tuning information, why not recognize the request, and try to supply the demand?

[Aloicious]

If you look at how Ford defines it, there's just two different slopes. GM has one slope (table vs pressure) and a time offset. The Ford "low slope" IS the the same effective function as the GM SPA table. They just define the mass versus time relationship from different angles. GM assumes nominal rail pressure for the SPA table since there's no axis for pressure in the table. Could there be more precision with a pressure axis? Sure. Is it needed? Would the benefit outweigh the necessary software code and engineering effort to support it? Probably not, so they focus calibrators' time elsewhere. It's a matter of "knowing when to say when."

I understand how ford uses the trendline of the measured actual small pulsewidths to help maintain the linearization of the injector charactoristics at small injecton pulsewidths. what I question is the foudation of where this data came from and how it translates to a GM PCM. when you say that the linear slope 'IS the same effective fuction as the GM SPA table' but yet provides a very different result when plotted compared to simmilar injectors from stock GM data, it makes me question the data itself, or perhaps the interpolation of the data. you very well may be 100% correct and everything, and the linear trend of the small pulse may be perfectly fine and very much within running spec, but I've never been one to just take data I can't confirm and blindly use it. expecially when the results vary alot from the standard of GM stock tuning tables.

here's some examples of what I'm talking about for those who aren't aware of how you do the interpolation on these injectors, the image on the left is a stock GM injector SPA table, on the right is a injector table (all are the same) for a bosch injector made like you instruct in your DVD (out of respect for your work, and this being a public posting, I DID NOT use the exact numbers from your spreadsheet, but they're close. and the axis labels have been blanked, but each table on the right has the exact same #'s, and each one is referenced to the #'s of the table on the right) I know they will not match perfectly simply because they're not the same injectors, but the table trends can be compared. for an accurate trend comparison between the two. again I'm not stating you're wrong, or the data is bad, but with a comparison like this and no way of verifying what is given to us, kinda makes me question something.
http://i461.photobucket.com/albums/qq337/guitargeek1968/SPAcomparison.jpg

[eficalibrator]

For example, If you took a course at a university, you wouldn't expect the professor to only give answers to the corsework and exams, you'd expect him to teach the formulas, explain the principles, and give you the background needed to actually learn something.

I fully understand that you make your living off of teaching people this kind of stuff and you may be hesitant to share information like this publically, especially when its a part of how you obtain your livelyhood.

When I was taking classes in college, I was also paying a LOT of money to be trained at that level of detail. It was far more expensive than any of my own private classes with a much worse instructor:student ratio. Yes, the training is a business for me, so I don't see a business case for making public the exact knowledge in question here. The market of skilled users such as yourselves is honestly too small to make enough money from such training unless I priced it somewhere that most would consider completely unreasonable. This is why I'm respectfully choosing to retain my position as a consultant on the matter instead. I still have several consulting clients who have called upon me specifically because I've been able to successfully correlate this data and prove it repeatedly in real world applications.

Since I don't mind pointing you guys in the right direction occasionally, let me take one of your examples and attempt to show the connection.

One of the first key requirements is to align the axes on a single injector application. To avoid comparing apples and oranges, let's look at how one would slice up a GM characterization into Ford-type units. (If you can go one way, the other is also possible) In the attached pic, I started with your first GM example.

http://forum.efilive.com/attachment.php?attachmentid=7190&d=1266363831

The first line of interest is the black horizontal line. This is effectively at zero time adjustment, which means that no shift is necessary to get the raw values from the linear IFR table to lay upon the actual mass delivered for that injection time. This is the region above the Ford "Breakpoint" where we consider the injector to be more or less completely linear in mass delivery versus time.

Next, we look at the red diagonal line. This represents a reasonable linear fit through the low end of the data. It's units of time adder per unit of raw injection time from the IFR table, so some conversion is required to get back to mass adjustments, but it's possible. The important thing here is that we can draw a straight line through a bunch of this data with only minor deviations. (Remember that the raw differences here are hundredths of milliseconds that likely have next to no noticeable effect upon actual mass delivery)

Finally, we recognize a compromised area in the blue triangle where there is a visible gap between the two linear fits and the curve of reality. The big question here is whether this gap matters. I would argue that if you're looking at 3% or less difference in mass delivered, you're getting an "A" in most engineering classes. Even a "B" or "C" still passes since there's a LOT of other sources of potential combustion and measurement error in a piston engine.

Also, values in the SPA table below the some minimum are pretty much academic since the PCM won't let you go there anyway. The minimum here is really the minimum final allowed pulsewidth minus the value in the SPA table. If you have very small adjust values in the table, the minimum is closer to the raw minimum define in the calibrate-able value. Everything below that doesn't matter if you clip it.

Hopefully this helps your understanding a bit. If a select group of you really want to dig deeper, perhaps I could arrange a closed class where we address topics deeper than most are prepared to address, be they injector or otherwise based.

[Aloicious]

Yes, the training is a business for me, so I don't see a business case for making public the exact knowledge in question here....This is why I'm respectfully choosing to retain my position as a consultant on the matter instead.

IMO I still think that sharing the formulas in question wouldn't detract from your income, but I understand your position on it as well, and I can at least respect your decision to not publically post it.

As a scientifically minded group we are here, we like to disect and verify data that is provided to us, and when the author of the data in question doesn't provide the tools (i.e. formulas, etc) to do so (for whatever reason), we bring into question the validity of either the author or the data and methood. and sometimes we can be fairly tactless when expressing our discontent in the matter, and all too often it just becomes a pissing match. Thats what I'm trying to avoid with my long rambling posts. just trying to preserve civility and retain a productive intellectual dialoge.



The first line of interest is the black horizontal line. This is effectively at zero time adjustment, which means that no shift is necessary to get the raw values from the linear IFR table to lay upon the actual mass delivered for that injection time. This is the region above the Ford "Breakpoint" where we consider the injector to be more or less completely linear in mass delivery versus time.

Next, we look at the red diagonal line. This represents a reasonable linear fit through the low end of the data. It's units of time adder per unit of raw injection time from the IFR table, so some conversion is required to get back to mass adjustments, but it's possible. The important thing here is that we can draw a straight line through a bunch of this data with only minor deviations. (Remember that the raw differences here are hundredths of milliseconds that likely have next to no noticeable effect upon actual mass delivery)

Finally, we recognize a compromised area in the blue triangle where there is a visible gap between the two linear fits and the curve of reality. The big question here is whether this gap matters. I would argue that if you're looking at 3% or less difference in mass delivered, you're getting an "A" in most engineering classes. Even a "B" or "C" still passes since there's a LOT of other sources of potential combustion and measurement error in a piston engine.

Also, values in the SPA table below the some minimum are pretty much academic since the PCM won't let you go there anyway. The minimum here is really the minimum final allowed pulsewidth minus the value in the SPA table. If you have very small adjust values in the table, the minimum is closer to the raw minimum define in the calibrate-able value. Everything below that doesn't matter if you clip it.

Okay, that does answer a bit of my questions, I was unaware that ford used a separate high slope to define the higher SPA section, (okay I re-read stuff and I just don't know how to articulate very well, I meant that I was just mainly looking at trendlines over the whole table which provided a much different slope than the loslope alone, and didn't realize ford just accepted the high slope error). as far as the low end plateau, is that just as far as the ford injector calibrations go, since the PCM rarely (if ever) commands that low of a pusle? what about with DFCO? its been a while since I've logged with DFCO on, but IIRC I have seen some extremely low pulsewidths there, especially with some of the larger injectors, which may come close to the low end of the SPA table (but I don't have access to my logs at the moment, so I can't verify a specific low pulse number).

since the low pulse portion of the graph is somewhat academic, theoretically, shouldn't the loslope line extend all the way to zero, and not plateau off?

I'm entirely too OCD when it comes to my truck and tuning.

[WHYTRYZ06]

too much useless info here...:) J/K

[mr.prick]

Can the SPA {B4005} row be tracked with GM.IBPW or
does that PID include all offset/adders?
If not is there a way to track this table and make small adjustments or
must this table be built completely of known/calculated data?

We are told the injector tables need to be populated with known values but
vehicles that share the same injectors can have completely different values,
leading me to believe they need to be tweaked to get everything inline.
How can some injectors use canned values when OEM installed can differ between vehicles?

[samh_08]

We are told the injector tables need to be populated with known values but
vehicles that share the same injectors can have completely different values,
leading me to believe they need to be tweaked to get everything inline.
How can some injectors use canned values when OEM installed can differ between vehicles?
I agree..Even the 'known good' values contradict each other from tune to tune..:doh2:

[Aloicious]

Can the SPA {B4005} row be tracked with GM.IBPW or
does that PID include all offset/adders?
If not is there a way to track this table and make small adjustments or
must this table be built completely of known/calculated data?

We are told the injector tables need to be populated with known values but
vehicles that share the same injectors can have completely different values,
leading me to believe they need to be tweaked to get everything inline.
How can some injectors use canned values when OEM installed can differ between vehicles?

as far as I know, there is not a way to log the SPA alone (or derrive it from logged drive data). it has to be either tuned with known data, or tested for (though there is only one place I know of outside of OEM labs that can test for the SPA, which is Paul with YAW power). not only that, but even if we could log the SPA, I don't know how we would alter the values to correct it other than pure trial and error, which IMO wouldn't work good on a table like this, since its not measuring something like airflow or IFR which can be studied well with things like AFR, the SPA acutally effects the linearality of the injector to try and keep the injectors behavior predictable. (not only that but the OEM tables are kinda generalizations, if you have them tested for SPA, you'll see that kinda like the IFR of an injector can vary by a little amount from injector to injector, so will the SPA values, and voltage offsets, etc.)

as far as injector data being different from tune to tune, even with the same injectors, some of it has to do with GM OEM calibrators just learning more about the injectors and evolving/refining the table as more and more data is gathered on the said injector over time, I think you'll find, (for the most part) that same injectors in the same year (and OS) are very simmilar (if not identical) for example, check out a '02 LS1 Vette vs. an '02 LS1 camaro, vs. an '02 LS6 Z06, vs. a, '02 LS1 Firebird, you will find small variations, but they are virtually (and for all intents and purposes) identical, now you could compare that with a later LS1 tune with the same injectors and I bet the difference would be much more prominent. I'm sure there are other reasons too.

[joecar]

...
GM.IBPW or
does that PID include all offset/adders?
...GM.IBPW is the final value, it includes all the modifiers/adders/offsets...

I just spoke with Mick and he confirmed this.

[5.7ute]

Can the SPA {B4005} row be tracked with GM.IBPW or
does that PID include all offset/adders?
If not is there a way to track this table and make small adjustments or
must this table be built completely of known/calculated data?

We are told the injector tables need to be populated with known values but
vehicles that share the same injectors can have completely different values,
leading me to believe they need to be tweaked to get everything inline.
How can some injectors use canned values when OEM installed can differ between vehicles?

GM.IBPW does include all offset adders & can be "proven" quite easily.
Calculate the amount of fuel that needs to be injected by logging your airmass DMA pid. (Using the DMA pids tells you what the PCM is basing its calculations on.) Divide this by the commanded AFR to give you the fuelmass that needs to be injected. Then divide this by your IFR to give you the pulsewidth in seconds needed to supply that amount of fuel. Multiply by 1000 to give you milliseconds. I call this CALC.IPW & use this to base a lot of calculations on.
You will see quite clearly that GM.IBPW & CALC.IPW do not match by a reasonable difference.(CALC.IPW will be significantly smaller than GM.IBPW)
In areas where SPA, default pw etc is not used you will see the difference tracks very close to your volt/manvac offset.
Still working on the SPA contribution but it certainly appears to be based on the CALC.IPW pid not GM.IBPW.

[Aloicious]

GM.IBPW is the final value, it includes all the modifiers/adders/offsets...

I just spoke with Mick and he confirmed this.

good to know.