M-9353-BB302 Injector Voltage Offset work for sharing/ feedback

**Gojira94** · 01-29-2021

Here are the 47# and 80# sheets. Had to zip them because .xlsx still isn't supported...

Values you need to input are filled tan. Other colors are there to visually represent important things like minPW, slope, static values from TunerPro, etc.
All voltages are assumed to be 14V for the sake of sanity.
Fuel is modeled to be ethanol blended 93 octane gasoline, non-winter blend, 5-7% ethanol content, with specific gravity of .740, 571.5623862cc/gallon.

The first 4 tabs only require values from the spec sheet from Ford, plus one cell you need to fill for 43.5#. The graph is there to help visually find the value needed, consistent with the overall shape. It will be very, very close. 39.15 and 50.03 are 10.88 apart and 43.5 falls about 45% of the way between the 2 points.

The VoltageOffset tab will automatically graph the Ford spec sheet points for 6, 8, 10, 11, 12, 14 & 15V, You need to flesh out the graph with the remaining values in the tan cells. Once satisfied, paste those 32 GM values into TunerPro. Hit the compare button to see what TunerPro does with rounding the values to its nearest increments (of about 15.267 - 15.3). Paste those values into column C. The graph in the LU47 and LU80 I've provided show the variation "delta" between calculated/ hand drawn data curve and how TunerPro rounds to the nearest increment of 15.3usec. TunerPro values are overlaid in red on top of the calculated and hand entered values in blue. Below 6V probably isn't important, even during cranking. None of my cars have ever turned over with less than 10.5 - 11Vbat on an extremely lucky day...

HiSlope and LoSlope tabs are much the same as the first 4, where you enter the Ford sheet values and craft a value for 43.5# with the assistance of the graph.

The PWAdder tab requires the most effort but it pulls almost everything needed from the other tabs. Primarily you deal with columns C and H. Column C represents the TunerPro 'Low Pulsewidth Adder' table. Columns A & G are the TunerPro xdf points with some added below 488usec to reach zero for graphing down to the offset. Orange below, green above, yellow on either side and red at the breakpoint. You need to add rows to create 1) the MinPW in ms and it shows the delivered fuel per pulse and how many cc/min that is, for the graph at the bottom; 2) the breakpoint fuel mass in both high and low slopes. This is the intersect between low and high slopes, which we will cross on the graph by offsetting the high slope until the breakpoint fuel mass in each column are overlaid on the graph. The offset, or time it takes for the injector to actually begin to open is built in, pulling from the InjOffset tab, using 14V and putting those values in column B.

Watch the formulas when you insert rows in and fill down the formulas on this sheet. Things like:

=(A11*LoSlope!D5)+(C11*LoSlope!D5) will increment "D5" to "D6" so make sure those 2 D5 stay D5.

=G7*HiSlope!D5 will do the same, so keep it "D5"

Columns E & J will be fine and preserve their formulas when you fill down or up the formulas (cc/min at PW "A" Lo and cc/min at PW "A" Hi)

"Bending" the low slope up to the high slope to get the offset values:

First, insert rows for offset and breakpoint (breakpoint mass on both Low and High slopes as noted above). Tweak the column A and G values for this to get it to match for 5 places to the right of the decimal point. The actual breakpoint mass at 43.5psi is noted below the Low table, in red. (Note - on either side of that, there are for reference, the low slope and high slope flow rates in cc/ms at 43.5psi).
Next, look at H3. It's something like =G3+0.xxxx, where 0.xxxx is the artificial offset we're adding to the Hi slope so it will intersect the low slope at the breakpoint. Just dial it in and fill down the formula =G3+0.xxxx from H3 to H36 until the red and blue data points for the breakpoint overlap. The zoom function in the View menu in Excel is very helpful between 200% - 300% for this.
Now that the Hi slope and Lo slope breakpoints overlap, we can start "bending" the Lo slope up until it overlaps the Hi slope line. Again, 200-300% zoom is great for helping you get the lines to overlap almost seamlessly. The idea is that when we convert back to usec for TunerPro's LT1 xdf we're no more than 10-15 millionths of a second off in calculations and the delta the xdf value increments produce.
Start entering values into C3, C4, C5 and so on, zooming and tweaking until the lines are almost seamlessly stacked, up to the breakpoint value, which will be 0.

I'm interested in looking now at the smaller injectors, in the 19# range for the sake of curiosity.

Disclaimer:
Again, I want to be clear that this is theoretical work and assumes my math modeling is correct and I haven't screwed anything up in Excel itself. Anyone and everyone with more math and injector science skills please chime in and help correct any missed assumptions or math, etc.

**Gojira94** · 01-30-2021

***EDIT: Corrected sheets per issue below uploaded to post 16.***

I found an 'oops.'

Some calibration summary sheets have different max pressure values in BKCOMP, LSCOMP, HSCOMP and OFFCOMP. Some have a highest value of 60.03 and some use 64.96, like the LU47 and probably some others. It's not a used value other than for graphing but I'm going to tweak and upload a new version of the sheet to indicate it's a value that needs to be entered from the calibration summary sheet.

**JimCT_9C1** · 01-30-2021

Wow. I've got some catching up to do.

I took a look at some of the data plotted in the first graph in Post#7 and they looked close to values I came up with. I used a similar but slightly different approach to get there.

I did notice an apparent difference in the first plot in Post #7 and the Tunerpro offset table. It appears that the table uses the Ford defined offset as compared to the GM offset definition which is based on extrapolating the linear high flow region slope to low pulsewidths (see links in Post #11). The GM offset looks to be about 0.63 msec vs the 0.86 msec in the table. This would then increase the low pulse adder, which at 0.488 msec BPW looks about 0.16 on the graph. I sketched a green line in the plot below to help show what I am saying. **Edit: Added labels for clarity**

plot.JPG

It's interesting that some folks have not adjusted or just zeroed the low pulse adders. My LT1 idles at about 3.5 msec with stock injectors, which is above the low adder region. The fueling here is also above the 30# injector breakpoint, so the 30#'s would also be on the linear slope and beyond where the low adders are in effect. If only talking idle, I can see how these can be off and still behave. I am still paying attention to getting them right though, since they affect other areas of the tune.

For 4 bar applications, I found a spreadsheet at the below link. This could provide some insights or a way to crosscheck data:
https://forum.hptuners.com/showthrea...on-spreadsheet

Hope you find the above helpful, and thanks again for sharing your work!

Jim

**Gojira94** · 02-01-2021

Originally Posted by JimCT_9C1

My LT1 idles at about 3.5 msec with stock injectors, which is above the low adder region. The fueling here is also above the 30# injector breakpoint, so the 30#'s would also be on the linear slope and beyond where the low adders are in effect. If only talking idle, I can see how these can be off and still behave. I am still paying attention to getting them right though, since they affect other areas of the tune.

What are you using to monitor/ log this?

That's one thing that's bothered me- not having a quick reference for commanded usec/pulse across the RPM vs MAP or vs gm/sec airflow range. I could probably extrapolate that with a spot-on set of VE tables for stock and/ or my particular setup. I'll just have to start doing some datalogging and get some actual commanded pulsewidths from idle to rev limit. I'd have imagined that low adders would need to be in effect for a stock engine/ tune, target idle speed of 800RPM (M6) or 800 in gear/ 650 park & neutral (A4). Particularly for stick cars to avoid lean surge/ chugging at idle into launch mode/ acceleration enrichment.

It is also apparent that I need to adjust my MAF tables at this point. The dyno tune I paid for in 2009 used stock, unaltered tables. If it was tuned "appropriately" fat across the board so stock tables worked, I can understand an older school of thought and "it works" way of doing things, but now that I'm trying to accurately model behavior and response I've gone back through and changed a number of things accordingly. Now that I seem to be leaner everywhere, MAF table changes should yield additional benefit. Datalogging now and wideband as soon as feasible are next steps for my own car.

Meanwhile, here's another 47# injector. M-9593-G302. I'll post up the 19# M-9593-C302 a little later.

**Gojira94** · 02-02-2021

Here's the older Ford 19# M-9593-C302. It needs offset much further up into the 2ms/ 2000usec range and its breakpoint is later/ higher and its MinPW is notably larger. The BKCOMP and OFFCOMP tables have dips and spikes with slightly odd shapes.

**JimCT_9C1** · 02-03-2021

I log using EEHack. Injector pulsewidth is on the Dashboard in the fueling block.
If I want to do something more elaborate than EEHack's built-in functions, I just export the log to a csv file and go from there.

You might be able to get Trimalyzer to do what you want, but I haven't dug into it for that.

Jim

**kur4o** · 02-03-2021

I found some stock lsX injectors use negative adder at the low pulse. So instead of adding they substract. Not sure if ee hack can handle negative offset without modifications.
I guess they flow much more than needed at low pulse widths.

**JimCT_9C1** · 02-06-2021

That's one thing that's bothered me- not having a quick reference for commanded usec/pulse across the RPM vs MAP or vs gm/sec airflow range.

You might be able to get Trimalyzer to do what you want, but I haven't dug into it for that.

Confirmed Trimalyzer supports this - v1.5 makes it easy.
Thankyou Steveo!

Jim

**Gojira94** · 02-08-2021

Originally Posted by kur4o

I found some stock lsX injectors use negative adder at the low pulse. So instead of adding they substract. Not sure if ee hack can handle negative offset without modifications.
I guess they flow much more than needed at low pulse widths.

And would flow even more at 3 bar. Clearly some LSX injectors wouldn't be well represented on the 16188051, and probably a great number of others that would otherwise fit physically. Unless it was a pretty wild forced induction build, but that would be better suited for an aftermarket management system anyway.

I'm going to explore some other injectors from Accel, Bosch, maybe a couple of other manufacturers, for the LTX platform with OE PCM. Then I'm going to spend some time with HP Tuners and flesh out its injector characterization and start a library of those for HPT on 411, probably do a separate thread.